Movatterモバイル変換

Network Working Group                                    D. Eastlake 3rdRequest for Comments: 1898                                     CyberCashCategory: Informational                                        B. Boesch                                                               CyberCash                                                              S. Crocker                                                               CyberCash                                                                M. Yesil                                                               CyberCash                                                           February 1996CyberCash Credit Card Protocol Version 0.8Status of this Memo   This memo provides information for the Internet community.  This memo   does not specify an Internet standard of any kind.  Distribution of   this memo is unlimited.Abstract   CyberCash is developing a general payments system for use over the   Internet.  The structure and communications protocols of version 0.8   are described.  This version includes credit card payments only.   Additional capabilities are planned for future versions.   This document covers only the current CyberCash system which is one   of the few operational systems in the rapidly evolving area of   Internet payments. CyberCash is committed to the further development   of its system and to cooperation with the Internet Engineering Task   Force and other standards organizations.Acknowledgements   The significant contributions of the following persons (in alphabetic   order) to this protocol are gratefully acknowledged:        Bruce Binder, Judith Grass, Alden Hart, Steve Kiser, Steve        Klebe, Garry Knox, Tom Lee, Bob Lindenberg, Jim Lum, Bill        Melton, Denise Paredes, Prasad Chintamaneni, Fred Silverman,        Bruce Wilson, Garland Wong, Wei Wu, Mark Zalewski.   In addition, Jeff Stapleton and Peter Wagner made useful comments on   the first version of this memo.Eastlake, et al              Informational                      [Page 1]

RFC 1898                 CyberCash Version 0.8             February 1996History   For historic purposes, it should be noted that this document was   first posted as an Internet draft, and thus made publicly available,   on 8 July 1995.Table of Contents1. Overall System..........................................31.1 System Overview........................................31.2 Security Approach......................................51.2.1 Authentication and Persona Identity..................51.2.2 Privacy..............................................61.3 Credit Card Operation..................................62. General Message Wrapper Format..........................72.1 Message Format.........................................72.2 Details of Format......................................82.3 Body Parts.............................................82.4 Transparent Part.......................................92.5 Opaque Part...........................................102.6 Trailer...............................................102.7 Example Messages......................................113. Signatures and Hashes..................................123.1 Digital Signatures....................................123.2 Hash Codes............................................134. Specific Message Formats...............................134.1 Persona Registration and Application Retrieval........144.1.1 R1 - registration...................................144.1.2 R2 - registration-response..........................154.1.3 GA1 - get-application...............................164.1.4 GA2 - get-application-response......................174.2 Binding Credit Cards..................................184.2.1 BC1 - bind-credit-card..............................184.2.2 BC4 - bind-credit-card-response.....................204.3 Customer Credit Card Purchasing Messages..............214.3.1 PR1 - payment-request...............................214.3.2 CH1 - credit-card-payment...........................234.3.3 CH2 - charge-card-response..........................244.4 Merchant Credit Card Purchasing Messages..............254.4.1 CM1 - auth-only.....................................264.4.2 CM2 - auth-capture..................................283.4.3 CM3 - post-auth-capture.............................284.4.4 CM4 - void..........................................304.4.5 CM5 - return........................................324.4.6 CM6 - charge-action-response........................324.4.7 The MM* Message Series..............................344.4.8 CD1 - card-data-request.............................354.4.9 CD2 - card-data-response............................37Eastlake, et al              Informational                      [Page 2]

RFC 1898                 CyberCash Version 0.8             February 19964.5 Utility and Error Messges.............................384.5.1 P1 - ping...........................................394.5.2 P2 - ping-response..................................394.5.3 TQ1 - transaction-query.............................404.5.4 TQ2 - transaction-cancel............................414.5.5 TQ3 - transaction-response..........................424.5.6 UNK1 - unknown-error................................444.5.7 DL1 - diagnostic-log................................464.5.8 DL2 - merchant-diagnostic-log.......................474.6 Table of Messages Described...........................485. Future Development.....................................495.1 The Credit Card Authorization/Clearance Process.......495.2 Lessons Learned.......................................506. Security Considerations................................51      References................................................51      Authors' Addresses........................................521. Overall System   CyberCash, Inc. of Reston, Virginia was founded in August of 1994 to   partner with financial institutions and providers of goods and   services to deliver a safe, convenient and inexpensive system for   making payments on the Internet.  The CyberCash approach is based on   establishing a trusted link between the new world of cyberspace and   the traditional banking world.  CyberCash serves as a conduit through   which payments can be transported quickly, easily and safely between   buyers, sellers and their banks.  Significantly - much as it is the   real world of commerce - the buyer and seller need not have any prior   existing relationship.   As a neutral third party whose sole concern is ensuring the delivery   of payments from one party to another, CyberCash is the linchpin in   delivering spontaneous consumer electronic commerce on the Internet.1.1 System Overview   The CyberCash system will provide several separate payment services   on the Internet including credit card and electronic cash.  To gain   access to CyberCash services, consumers need only a personal computer   with a network connection.  Similarly, merchants and banks need make   only minimal changes to their current operating procedures in order   to process CyberCash transactions, enabling them to more quickly   integrate safe on-line payments into their existing service   offerings.  Communications with banks are over existing financial   communications networks.Eastlake, et al              Informational                      [Page 3]

RFC 1898                 CyberCash Version 0.8             February 1996   To get started, consumers download free software from CyberCash on   the Internet.  This software establishes the electronic link between   consumers, merchants and their banks as well as between individuals.   To make gaining access to the CyberCash system even easier, CyberCash   "PAY" buttons may be incorporated into popular on-line service and   software graphical user interfaces so that consumers using these   products can easily enter the CyberCash system when they are ready to   make payments for goods and services.  Consumers need not have any   prior relationship with CyberCash to use the CyberCash system.  They   can easily set up their CyberCash persona on-line.   Transactions are automated in that once the consumer enters   appropriate information into his own computer, no manual steps are   required to process authorization or clearance transactions through   the entire system.  The consumer need only initiate payment for each   transaction by exercising the pay option on an electronic form.   Transactions are safe in that they are cryptographicly protected from   tampering and modification by eavesdroppers. And they are private in   that information about the consumer not relevant to the transaction   is not visible to the merchant.      +------------+            +------------+      |            |            |            |      |  Internet  |            |  Internet  |      |  customer  +------------+  merchant  +      |            |            |  /         |      +------------+            +------------+                                /                               /                   +------------|-+                   | CyberCash  | |                   |     server | |                   +-----+------|-+                         |      |                         |      |          +--------------+------|---------+          | +--------+       +--+-------+ |          | | card   +-------+ / charge | |          | | issuer |       | acquirer | |          | +--------+       +----------+ |          |                               |          |      The Banking System       |          +-------------------------------+                   SYSTEM OVERVIEWEastlake, et al              Informational                      [Page 4]

RFC 1898                 CyberCash Version 0.8             February 19961.2 Security Approach   The CyberCash system pays special attention to security issues.  It   uses encryption technology from the world's leading sources of   security technology and is committed over time to employing new   security technologies as they emerge.1.2.1 Authentication and Persona Identity   Authentication of messages is based on Public Key encryption as   developed by RSA.  The CyberCash Server maintains records of the   public key associated with every customer and merchant persona.  It   is thus able to authenticate any information digitally signed by a   customer or merchant regardless of the path the data followed on its   way to the server.  The corresponding private key, which is needed to   create such digital signatures, will be held by the customer or   merchant and never revealed to other parties.  In customer software,   the private key is only stored in an encrypted form protected by a   passphrase.   While the true CyberCash identity of a customer or merchant is   recognized by their public/private key pair, such keys are too   cumbersome (over 100 hex digits) to be remembered or typed by people.   So, the user interface utilizes short alphanumeric ID's selected by   the user or merchant for purposes of specifying a persona.  CyberCash   adds check digits to the requested ID to minimize the chance of   accidental wrong persona selection.  Persona IDUs are essentially   public information.  Possession of an persona ID without the   corresponding private key is of no benefit in the current system.   Individuals or organizations may establish one or more CyberCash   customer personas directly with CyberCash.  Thus, an individual may   have several unrelated CyberCash personas or share a CyberCash   persona with other individuals.  This approach provides a degree of   privacy consistent with Internet presence generally and with cash   transactions specifically.  However, persona holders who wish to use   a credit card for purchases in conjunction with their CyberCash   persona must first meet such on-line identification criteria as the   card issuing organization requires.   Control over a CyberCash persona is normally available only to an   entity that possesses the private key for that persona.  However, a   special provision is made to associate an emergency close out   passphrase with a CyberCash persona.  On receipt of the emergency   close out passphrase, even if received over insecure channels such as   a telephone call or ordinary email, CyberCash will suspend activity   for the CyberCash persona.  This emergency close-out passphrase can   be stored separately from and with somewhat less security than theEastlake, et al              Informational                      [Page 5]

RFC 1898                 CyberCash Version 0.8             February 1996   private key for the persona since the emergency passphrase can not be   used to divert funds to others. This provides some protection against   loss or misappropriation of the private key or the passphrase under   which the private key in kept encrypted.  In the cash system, the   emergency close-out passpharase may also transfer the persona balance   to a designated bank account.1.2.2 Privacy   Encryption of messages use the Digital Encryption Standard (DES),   commonly used in electronic payment systems today.  It is planned to   superencrypt (i.e., encrypted more than one level) particularly   sensitive information, such as PIN numbers, and handle them so that   the plain text readable version never exists in the CyberCash system   except momentarily, within special purpose secure cryptographic   hardware that is part of the server, before being re-encrypted under   another key.   The processing of card charges through the CyberCash system is   organized so that the merchant never learns the customerUs credit   card number unless the merchantUs bank chooses to release this   information to the merchant or it is required for dispute resolution.   In addition, the server maintains no permanent storage of card   numbers.  They are only present while a transaction involving that   card is in progress.  These practices greatly reduce the chance of   card number misappropriation.1.3 Credit Card Operation   Using the CyberCash system for credit card transactions, once price   has been negotiated and the consumer is ready to purchase, the   consumer simply clicks on the CyberCash "PAY" button displayed on the   merchant interface, which invokes the merchant CyberCash software.   The merchant sends the consumer an on-line invoice that includes   relevant purchase information which appears on the customerUs screen.   (See PR1 message.)  The consumer adds his credit card number and   other information by simply selecting from a list of credit cards he   has registered to his CyberCash persona.  All this information is   digitally signed by the customer's CyberCash software, encrypted, and   passed, along with a hash code of the invoice as seen by the   customer, to the merchant.  (See CH1 message.)   Upon receipt, the merchant adds additional authorization information   which is then encrypted, electronically signed by the merchant, and   sent to the CyberCash Server.  (See CM1 & CM2 messages.)  The   CyberCash Server can authenticate all the signatures and be sure that   the customer and merchant agree on the invoice and charge amount.   The CyberCash Server then forwards the relevant information to theEastlake, et al              Informational                      [Page 6]

RFC 1898                 CyberCash Version 0.8             February 1996   acquiring bank along with a request on behalf of the merchant for a   specific banking operation such as charge authorization.  The bank   decrypts and then processes the received data as it would normally   process a credit card transaction.  The bank's response is returned   to the CyberCash Server which returns an electronic receipt to the   merchant (see CM6 message) part of which the merchant is expected to   forward to the customer (see CH2 message).  The transaction is   complete.2. General Message Wrapper Format   Version 0.8 of the external format for the encoding of CyberCash   messages is described below.  CyberCash messages are stylized   documents for the transmission of financial data over the Internet.   While there are numerous schemes for sending information over the   Internet (HTTP, SMTP, and others), each is attached to a specific   transmission mechanism.  Because CyberCash messages will need to   travel over each of these media (as well as others) a transmission   independent mechanism is needed.2.1 Message Format   CyberCash messages consist of the following components:   1. Header - defines the start of the CyberCash message and includes      version information.   2. Transparent Part - contains information that is not private.   3. Opaque Part(s) - contains the financial information in the      message and is both privacy protected as well as tamper protected.      An opaque part is not present in some messages. When present, the      opaque part usually provides tamper protection for the transparent      part.   4. Trailer - defines the end of the CyberCash message and includes a      check value to enable the receiver to determine that the message      has arrived undamaged. Note: this check value is intended only to      detect accidental damage to the message, not deliberate tampering.      No null characters (zero value) or characters with the eighth bit      on are permitted inside a CyberCash message.  "Binary" quantities      that might have such byte values in them are encoded in base64 as      described inRFC 1521.Eastlake, et al              Informational                      [Page 7]

RFC 1898                 CyberCash Version 0.8             February 19962.2 Details of Format   The header consists of a single line which looks approximately like   this        $$-CyberCash-0.8-$$   or like this        $$-CyberCash-1.2.3-Extra-$$   It includes a number of fields separated with the minus character "-"   1. "$$" - the literal string with the initial $ in column 1.   2. "CyberCash" - the literal string (case insensitive)   3. x.y or x.y.z - the version number of the message format.  x is the   primary version number.  y is a subversion number.  z, if present, is   a subsubversion number.   4. "Extra" - an optional additional alphanumeric string.   5.  "$$" - the literal string   Version numbers start at 0.7 and count up.  The ".z" is omitted when   z is zero.  0.7 and 0.8 are the test and initial shipped version of   the credit card system. 0.9 and 1.0 are expected to also incorporate   the test and initial shipped versions of the cash facilities as well   as improvements to the credit card system.   The "Extra" string is used within secure environments so that one   subcomponent can scribble a note to another with minimum overhead.   For example, a server firewall could put "HTTP" or "SMTP" here before   forwarding the message to the core server within the firewall   perimeter.2.3 Body Parts   The body parts of the message (both transparent and opaque) consist   of attribute value pairs in formats that are reminiscent of the   standard electronic mail header (RFC822) format. However, there are   some differences.   Attribute names start with and are composed predominantly of letters   and internal hyphens except that they sometimes end with a hyphen   followed by a number.  Such a trailing number is used when there is   logically an indexed vector of values.  Attribute names areEastlake, et al              Informational                      [Page 8]

RFC 1898                 CyberCash Version 0.8             February 1996   frequently referred to as labels.   If the label ends with a ":", thenRFC822 processing is done.  While   the existence of trailing white space is significant, all leading   white space on continuation lines is stripped.  Such lines are   wrapped at 64 characters in length, excluding any line termination   character(s).   However, if the label is terminated with a ";", this indicates a   free-form field where new-line characters and any leading white   space, after the initial space that indicates a continuation line, is   significant.  Such lines should not be wrapped except that, to avoid   other processing problems, they are forcibly wrapped at 200   characters.   Blank lines are ignored and do not signify a change  to  a  different   mode of line handling.   Another way of looking at the above is as follows: after having found   an initial $$ start line, you can treat any following lines according   to the first character.  If it is alphanumeric, it is a new label   which should be terminated with a ":" or ";" and indicates a new   label-value pair.  If it is a white space character, it indicates the   continuation of the value for the preceding new label line.  (Exactly   how the continuation is processed depends on the label termination   character.)  If it is "$", it should be the end line for the message.   If it is #, it is a comment line and should be ignored.  Other   initial characters are undefined.  (As of this date, no software   sends CyberCash messages with # lines but they are convenient for   commenting messages stored in files.)2.4 Transparent Part   The transparent part includes any clear-text data associated with the   financial transaction as well as information needed by CyberCash and   others to decrypt the opaque part(s).  It always includes a   transaction field which is the transaction number generated by the   requester and which is repeated in the response.  It always includes   a date field that is the local date and time at the requester and is   repeated in the response.  In all cases other than an initial   registration to establish a persona ID, it includes the requester's   persona ID.   On messages bound for the server, there is a "cyberkey:" field that   identifies which server public key was used to encrypt the session   key.Eastlake, et al              Informational                      [Page 9]

RFC 1898                 CyberCash Version 0.8             February 19962.5 Opaque Part   The opaque part consists of a single block of characters encoded   using base64 encoding (seeRFC 1521). The data in the opaque section   is always encrypted before encoding.   The label "opaque" or "merchant-opaque" precedes the opaque part   depending on whether the data was encrypted by the client or merchant   software.   On messages inbound to the server, the data to be opaqued is DES CBC   encrypted under a random transacton key and then that DES key is RSA   encrypted under one of the server's public keys.  The RSA encrypted   DES key appears as the first part of the base64 encoded field and is   not broken out as a separate value in the message.  The corresponding   outbound reply from the server can simply be DES encrypted under this   transaction key as there is enough plain text information to identify   the transaction and the customer or merchant will have remembered the   transaction key from the inbound message.   A signature is not generally necessary in the opaque part of a reply   message.  Knowledge of the transaction key is adequate   authentication.  In order for someone to forge the response, they   would have to know the server's private key to be able to get at the   transaction key.  It is assumed that if anyone tampered with the   response opaque part, the probability that it would decrypt to   something that would parse is insignificant.  (Just the fact that the   8th bit has to be off means a chance of 1 in 2**n where there are n   characters and that's ignoring the rest of the formatting.)  While   someone can tamper with the transparent part, this usually either has   no effect or means that the client won't find the transaction key, in   which case it's just a particular example of denial of service by   damaging a message.2.6 Trailer   The trailer is intended to close the message and provide a definitive   and parseable end of the message.   The trailer consists of several fields separated by "-" as in header.   1. "$$" - literal string.   2. "CyberCash" - literal string (case insensitive).   3. "End" - literal string (case insensitive).   4. transmission checksum.Eastlake, et al              Informational                     [Page 10]

RFC 1898                 CyberCash Version 0.8             February 1996   5.  "$$" - literal string.   The transmission checksum is the MD5 has of all printable characters   in the version number in the start line and those appearing after the   second $$ of the start line and before the first $$ of the trailer   line as transmitted.  Note that all white space is left out of this   hash, including any new-lines, spaces, tabs, carriage returns, etc.   The exact label terminators actually used (: or ;) are included as   would any # comment line.  Note that the optional "Extra" string in   the $ start line is not included.  The idea is to check correct   transmission while avoiding sensitivity to gateways or processing   that might change the line terminator sequence, convert tabs to   spaces, or the like.2.7 Example Messages   Simple message from a client:   $$-CyberCash-0.8-$$   id: DONALD-69   transaction: 918273645   date: 199512250102   cyberkey:CC1001   opaque:    GpOJvDpLH62z+eZlbVkhZJXtTneZH32Qj4T4IwJqv6kjAeMRZw6nR4f0OhvbTFfPm+GG    aXmoxyUlwVnFkYcOyTbSOidqrwOjnAwLEVGJ/wa4ciKKI2PsNPA4sThpV2leFp2Vmkm4    elmZdS0Qe350g6OPrkC7TKpqQKHjzczRRytWbFvE+zSi44wMF/ngzmiVsUCW01FXc8T9    EB8KjHEzVSRfZDn+lP/c1nTLTwPrQ0DYiN1lGy9nwM1ImXifijHR19LZIHlRXy8=   $$-End-CyberCash-End-jkn38fD3+/DFDF3434mn10==-$$   Message from a merchant:   $$-CyberCash-a.b.c-extra-$$   merchant-ccid: acme-69   merchant-date: 19951231115959   merchant-transaction: 987654321   label: value   labelx: multiple line      value...   # comment   # another comment line   label; text with a real     multi-line        format !   merchant-cyberkey: CC1001   merchant-opaque:Eastlake, et al              Informational                     [Page 11]

RFC 1898                 CyberCash Version 0.8             February 1996    C1Q96lU7n9snKN5nv+1SWpDZumJPJY+QNXGAm3SPgB/dlXlTDHwYJ4HDWKZMat+VIJ8y    /iomz6/+LgX+Dn0smoAge7W+ESJ6d6Ge3kRAQKVCSpbOVLXF6E7mshlyXgQYmtwIVN2J    66fJMQpo31ErrdPVdtq6MufynN8rJyJtu8xSNolXlqIYNQy5G2I3XCc6D3UnSErPx1VJ    6cbwjLuIHHv58Nk+xxt/FyW7yAMwUb9YNcmOj//6Ru0NiOA9P/IiWczDe2mJRK1uqVpC    sDrWehG/UbFTPD26trlYRnnY   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$3. Signatures and Hashes   Inbound CyberCash request messages normally have a signature, as   described below, of all of the messages fields outside of the   signature.  This signature is transmitted inside the opaque part of   the message.  It enables the server to authenticate the source of the   message.   Messages from a merchant to a client initiating a purchase sequence   have fields signed by the merchant.  These fields and this signature   are included by the client in the opaque part of their card purchase   message to the merchant so that, when all is passed on to the server,   it can verify that the client saw the information the merchant   intended.   More information on CyberCash signatures and the hash codes they are   based on, is given below.3.1 Digital Signatures   Digital signatures are a means of authenticating information.  In   CyberCash messages, they are calculated by first taking the hash of   the data to be authenticated, as described below, and then encoding   the hash using an RSA private key.   Anyone possessing the corresponding public key can then decrypt the   hash and compare it with the message hash.  If they match, then you   can be sure that the signature was generated by someone possessing   the private key which corresponded with the public key you used and   that the message was not tampered with.   In the CyberCash system, clients, merchants, and the server have   public-private key pairs.  By keeping the private key secret and   registering their public key with the server (for a merchant or   client) or publishing their public key or keys (for the server), they   can provide high quality authentication by signing parts of messages.   An RSA digital signature is approximately the size of the modulus   used.  For example, if that is 768 bits long, then the binary digital   signature would be 768 bits or 96 bytes long and its base 64 encoding   would be 128 bytes.Eastlake, et al              Informational                     [Page 12]

RFC 1898                 CyberCash Version 0.8             February 19963.2 Hash Codes   The hashes used in CyberCash messages are message digests.  That is,   a non-invertable fingerprint of a message such that it is   computationally infeasible to find an alternate message with the same   hash.  Thus the relatively small hash can be used to secure a larger   message.  If you are confident in the authenticity of the hash and   are presented with a message which matches the hash, you can be sure   it is the original message, at least as regards all aspects that have   been included in the hash.   The hash is calculated using the MD5 algorithm (seeRFC 1321) on a   synthetic message.  The synthetic message is composed of the labels   and values specified in a list for the particular hash.  Since the   hash is input order dependent, it is essential that the label-value   pairs be assembled in the order specified.  In some cases, a range of   matching labels is specified.  For example, "card*" to match card-   number, card-expiration-date, and all other labels starting with   "card".  In such cases, all existing matching labels are used in   ascending alphabetic order by ASCII character code.   If a label is specified in a signature list but is not present in the   label-value data on which the hash is being calculated, it is not   included in the hash at all.  That is, even the label and label   terminator are omitted from the synthetic message.   Before being hashed, the text of the synthetic message is processed   to remove all "white space" characters.  White space characters are   defined as any with an ASCII value of 32 (space) or less or 127   (rubout) or greater.  Thus all forms of new-line/carriage-return and   distinctions such as blank lines, trailing spaces, replacement of a   horizontal tab character by multiple spaces, etc., are ignored for   hash purposes.   MD5 hashes are 16 bytes long.  This means that the base 64 encoding   of such a hash will be 24 characters (of which the last two will   always be padding equal signs).4. Specific Message Formats   This section describes the formats of the Verison 0.8 CyberCash   messages by example with comments.  The reader in assumed to be   familiar with terms such as "acquirer", "PAN" (primary account   number), etc., defined in ISO 8583, and currency designations as   defined in ISO 4217. A few fields not relevant to current operations   have been removed to simplify this exposition.Eastlake, et al              Informational                     [Page 13]

RFC 1898                 CyberCash Version 0.8             February 1996   In the following example messages, signatures, hashes, and encrypted   sections are fake nonsense text and ids are fictitious.4.1 Persona Registration and Application Retrieval   The first step in customer use of CyberCash is registering a persona   using the customer application.  This is done with the R1 message   defined below.  The CyberCash server responds with the R2 message.   When the customer application learns that it is out of date, it can   use the GA1 request message to the server and its GA2 response to   download a new signed version of itself.4.1.1 R1 - registration   Description: This is the initial message sent to create a new       CyberCash persona.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   transaction: 123123213   date: 19950121100505.nnn   cyberkey: CC1001   opaque:    FrYOQrD16lEfrvkrqGWkajM1IZOsLbcouB43A4HzIpV3/EBQM5WzkRJGzYPM1r3noBUc    MJ4zvpG0xlroY1de6DccwO9j/0aAZgDi9bcQWV4PFLjsN604j3qxWdYn9evIGQGbqGjF    vn1qI1Ckrz/4/eT1oRkBBILbrWsuwTltFd84plvTy+bo5WE3WnhVKsCUJAlkKpXMaX73    JRPoOEVQ3YEmhmD8itutafqvC90atX7ErkfUGDNqcB9iViRQ7HSvGDnKwaihRyfirkgN    +lhOg6xSEw2AmYlNiFL5d/Us9eNG8cZM5peTow==   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: Generated using CyberCash encrypting public key       identified in CyberKey.   #####################################################################   Opaque Section Contents:   type: registration   swversion: 0.8win   content-language: en-us   requested-id: MyRequestedCCIDEastlake, et al              Informational                     [Page 14]

RFC 1898                 CyberCash Version 0.8             February 1996   email: myemail@myemailhost.com   pubkey:    0VdP1eAUZRrqt3Rlg460Go/TTs4gZYZ+mvI7OlS3l08BVeoms8nELqL1RG1pVYdDrTsX    E5L+wcGCLEo5+XU5zTKkdRUnGRW4ratrqtcte7e94F+4gkCN06GlzM/Hux94   signature:    v6JGmxIwRiB6iXUK7XAIiHZRQsZwkbLV0L0OpVEvan9l59hVJ3nia/cZc/r5arkLIYEU    dw6Uj/R4Z7ZdqO/fZZHldpd9+XPaqNHw/y8Arih6VbwrO5pKerLQfuuPbIom   #####################################################################   signature is of the following fields: transaction, date, cyberkey,       type, swversion, content-language, requested-id, email, pubkey   #####################################################################   Explanation:   content-language is taken from the MIME header field (seeRFC1766)       and is the language text messages should be generated in.  (only       en-us implemented at this time.   swversion used to check if client application is old.4.1.2 R2 - registration-response   Description: This message gives the success/failure response to R1.   #####################################################################   Sender: CyberServer   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   transaction: 12312313   date: 19950121100505.nnn   opaque:    r1XfjSQt+KJYUVOGU60r7voFrm55A8fP5DjJZuPzWdPQjGBIu3B6Geya8AlJfHsW11u8    dIv1yQeeYj/+l9TD1dXW21/1cUDFFK++J2gUMVv8mX1Z6Mi4OU8AfsgoCliwSkWmjSOb    kE62sAlZTnw998cKzMFp70TSlI3PEBtvIfpLq5lDCNbWidX8vFZV0ENUmMQ9DTP3du9w    fsFGvz1mvtHLT/Gj8GNQRYKF4xiyx4HYzTkSMhgU5B/QDLPS/SawIJuR86b9X0mwsr0a    gbGTzECPJTiKkrhxxMG/eymptsVQSLqNaTCx6w==   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: Same as session key for R1 for same Transaction and       connection (there may be no ID!).   #####################################################################   Opaque Section Contents:Eastlake, et al              Informational                     [Page 15]

RFC 1898                 CyberCash Version 0.8             February 1996   type: registration-response   server-date: 19950121100506.nnn   requested-id: MyRequestedCCID   response-id: CyberCashHandle   email: myemail@myemailhost.com   response-code: success/failure/etc.   pubkey:    0VdP1eAUZRrqt3Rlg460Go/TTs4gZYZ+mvI7OlS3l08BVeoms8nELqL1RG1pVYdDrTsX    E5L+wcGCLEo5+XU5zTKkdRUnGRW4ratrqtcte7e94F+4gkCN06GlzM/Hux94   swseverity: fatal/warning  [absent if ok]   swmessage; Tells CyberApp that it is obsolete.  Display this    text to the user.  [only present if SWSeverity present]   message;          Free text of the error/success condition.          This text is to be displayed to the person          by the CyberCash application...          In general this includes: duplicate-id, bad-signature,          or ill-formed-registration   #####################################################################   Signature is of the following fields: no-signature   #####################################################################   Explanation:   responseid is used to suggest a unique ID if the failure was due       to the requested ID being already in use... If the reason for       failure was not due to duplicate ID then this field may be       omitted.   responseid gives the actual ID with check characters appended if       success.   swseverity can warn user of old client application or indicate       failure due to old or known buggy version.4.1.3 GA1 - get-application   Description: Used by CyberApp to get an updated version.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   transaction: 123123213   date: 19950121100505.nnnEastlake, et al              Informational                     [Page 16]

RFC 1898                 CyberCash Version 0.8             February 1996   cyberkey: CC1001   opaque:    VHMS611wGkUmR6bKoI+ODoSbl7L5PKtEo6aM88LCidqN+H/8B4xM3LxdwUiLn7rMPkZi    xOGb+5d1lRV7WeTp21QYlqJr8emc6FAnGd5c0csPmcnEpTFh9xZDJaStarxxmSEwm2mw    l2VjEUODH6321vjoMAOFQWn7ER0o   $$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$   #####################################################################   Opaque Key: Generated using CyberCash encrypting public key identified      in CyberKey.   #####################################################################   Opaque Section Contents:   type: get-application   swversion: 0.8win   #####################################################################   Signature is of the following fields: no signature   #####################################################################   Explanation:   There may not be a customer persona so there is no ID.  There       may not be a customer public/private key pair so there is       no signature.  The swversion is mandatory so the server can       tell what to return.4.1.4 GA2 - get-application-response   Description: Return success and URL of up to date copy of CyberApp       or failure.   #####################################################################   Sender: CyberServer   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   transaction: 12312313   date: 19950110102333.nnn   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==Eastlake, et al              Informational                     [Page 17]

RFC 1898                 CyberCash Version 0.8             February 1996   $$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$   #####################################################################   Opaque Key: session key from GA1   #####################################################################   Opaque Section Contents:   type: get-application-response   server-date: 19950110102334.nnn   response-code: success/failure/etc.   message; Text message to be displayed to the user providing more       information on the success/failure.   swversion: 0.8win   application-url:http://foo.cybercash.com/server/0.8WIN.EXE   application-hash: lSLzs/vFQ0BXfU98LZNWhQ==   #####################################################################   Signature: none.   #####################################################################   Explanation:   application-hash is the MD5 of the binary of the application.   application-url & application-hash omitted on failure.   swversion is the version being transmitted to the customer.4.2 Binding Credit Cards   The CyberCash system is design to give the card issuing organization   control over whether a card may be used via the CyberCash system.   The customer, after having registered a persona with CyberCash as   described above, can then bind each credit card they wish to use to   their CyberCash persona.  This is done via the BC1 message from the   customer to their CyberCash server and the BC4 response from the   server.4.2.1 BC1 - bind-credit-card   Description: This is the initial message in the process of binding a       credit card to a CyberCash persona.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:Eastlake, et al              Informational                     [Page 18]

RFC 1898                 CyberCash Version 0.8             February 1996   $$-CyberCash-0.8-$$   id: MyCyberCashID   date: 19950121100505.nnn   transaction: 12312314   cyberkey: CC1001   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: generated from CyberCash encryption key identified in       CyberKey   #####################################################################   Opaque Section Contents:   type: bind-credit-card   swversion: 0.8win   card-number: 1234567887654321   card-type: mastercard   card-salt: 46735210   card-expiration-date: 05/99   card-name: John Q. Public   card-street:   card-city:   card-state:   card-postal-code:   card-country:   signature:    tX3odBF2xPHqvhN4KVQZZBIXDveNi0eWA7717DNfcyqh2TpXqgCxlDjcKqdJXgsNLkY7    GkyuDyTF/m3SZif64giCLjJRKg0I6mqI1k/Dcm58D9hKCUttz4rFWRqhlFaj   #####################################################################   signature is of the following fields: id, date, transaction,       cyberkey, type, swversion, card-number, card-salt,       card-expiration-date, card-name, card-street, card-city,       card-state, card-postal-code, card-country   #####################################################################   Explanation:   salt is needed so that the hash stored at the server is less       informative.  Server just remembers the "prefix" of the card       number and the hash of the combined card number and salt. If it       just hashed the card number, it would be recoverable with modestEastlake, et al              Informational                     [Page 19]

RFC 1898                 CyberCash Version 0.8             February 1996       effort by trying to hash all plausible numbers.  We don't want       to store the card numbers on the server because it would make       the server files too valuable to bad guys.4.2.2 BC4 - bind-credit-card-response   Description: Indicates that the process of binding a credit card       terminated.  Returns success or failure.   #####################################################################   Sender: CyberServer   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   id: mycybercashid   transaction: 12312314   date: 19950121100505.nnn   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: Session key from BC1 with same Transaction and ID   #####################################################################   Opaque Section Contents:   type: bind-credit-card-response   server-date: 19950121100506.nnn   swseverity: fatal/warning  [absent if ok]   swmessage; message about obsoleteness of customer software       to be shown to the customer.  [only present if SWSeverity present]   response-code: success/failure/etc.   card-number: 1234567887654321   card-type: visa   card-salt: 47562310   card-expiration-date: 01/99   card*: [other card* lines to also be given in CH.1 message]   message; Plain text for the user       can be multiple linesEastlake, et al              Informational                     [Page 20]

RFC 1898                 CyberCash Version 0.8             February 1996   #####################################################################   Signature is of the following fields: no-signature   #####################################################################   Explanation: All the card* lines can be saved as a blob to be       submitted in CH.1.  card-expiration-date, card-number, card-salt,       and card-type should always be present.   Depending on reason for failure, not all fields may be present.4.3 Customer Credit Card Purchasing Messages   In general, CyberCash involvement in the credit card purchasing cycle   starts after the user has determined what they are buying.  When they   click on the CyberCash payment button, a PR1 message is sent by the   merchant to the customer as the body of a message of MIME type   application/cybercash.   If the customer wishes to proceed, they respond to the merchant  with   a  CH1.   The merchant responds with a CH2 but between the receipt of   the CH1 and issuance of the CH2, the  merchant  usually  communicates   with the CyberCash server via the CM* messages.4.3.1 PR1 - payment-request   Description: This message is the first message that is defined       by CyberCash in the purchase-from-a-merchant process. The       shopping has completed.  Now we are at the point of paying       for the purchases.   #####################################################################   Sender: MerchantApp   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: payment-request   merchant-ccid: ACME-012   merchant-order-id: 1231-3424-234242   merchant-date: 19950121100505.nnn   note;     ACME Products     Purchase of 4 pairs "Rocket Shoes" at $39.95 ea.     Shipping and handling $5.00Eastlake, et al              Informational                     [Page 21]

RFC 1898                 CyberCash Version 0.8             February 1996     Total Price: 164.80     Ship to:          Wily Coyote          1234 South St.          Somewhere, VA 12345   merchant-amount: usd 164.80   accepts: visa:CC001, master:CC001,amex:CC001,JCPenny:VK005,macy:VK006   url-pay-to:http://www.ACME.com/CybercashPayment   url-success:http://www.ACME.com/ordersuccess   url-fail:http://www.ACME.com/orderfail   merchant-signed-hash:    a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh    Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD   $$-CyberCash-End-lSLzs/vFQ0BXfU98LZNWhQ==-$$   #####################################################################   Opaque Key: no opaque section   #####################################################################   Opaque Section Contents: no opaque section   #####################################################################   merchant-signed-hash is the signature under the merchant's       private key of the hash of the following fields: type,       merchant-ccid, merchant-order-id, date, note, merchant-amount,       accepts, url-pay-to, url-success, url-fail   #####################################################################   Explanation:   This message is signed by the merchant but the customer cannot       directly verify this signature. When the payment is made, the       Customer includes the signature with the hash (derived by the       customer directly) in the payment. If these do not match, the       CyberCash will not perform the payment function.   accepts: The client software will only recognized single word card   name in the accepts field of PR1. For example,     MasterCard     AmericanExpress   are recognized where as     Master card     American express   are not recognized. MasterCard and masterCard are both   recognized as master card.   Card type followed by key designator.  For main line credit cards,       this will be a CC*.  Client can use or ignore the * number as       it chooses.  For proprietary card, this will be VK* where * is       the CheckFree key to use (1 based).  Cards separated by comma,Eastlake, et al              Informational                     [Page 22]

RFC 1898                 CyberCash Version 0.8             February 1996       key designator follows card type and colon.   url-pay-to is where the CH1 should be sent.  url-fail and url-success       are where the browser should look after failure or success.4.3.2 CH1 - credit-card-payment   Description: This message represents the presentation of a "credit       card for payment".   #####################################################################   Sender: CyberApp   Receiver: MerchantApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: card-payment   id: myCyberCashID   order-id: 1231-3424-234242   merchant-ccid: ACME-012   transaction: 78784567   date: 19950121100505.nnn   pr-hash: c77VU/1umPKH2kpMR2QVKg==   pr-signed-hash:    a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh    Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD   cyberkey: CC1001   opaque:    iff/tPf99+Tm5P7s3d61jOWK94nq9/+1jOWK9+vr9+b+94n3tYzmiveJ9/+09/334ubg    3rWM5Ir3ier3/7WM5Ir36+v35v73ife1jOWK94n3/7T3/ffm5uD+7N339/f39/eq3ff3    9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3    5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw    3ard3Q==   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Opaque Key: Created using CyberCash encrypting public key in       CyberKey.   #####################################################################   Opaque Section Contents:   swversion: 0.8win   amount: usd 10.00   card*: [from successful BC4 (includes card-expiration-date,       card-number, card-type, and card-salt)]   signature:    meO38aULnoP09VhTS2E56tnuZBRRlGfbwqaleZ9zNnv7YjExJKBFxuaqYTUDEj427HHhEastlake, et al              Informational                     [Page 23]

RFC 1898                 CyberCash Version 0.8             February 1996    mm9BVmHRwCq6+8ylZXixGHI1I9A/ufAMrpqMIi6DS3PRlc8WC3CCWoAHyAqr   #####################################################################   signature is under client private key of the following fields:       type, id, order-id, merchant-ccid, transaction, date,       pr-hash, pr-signed-hash, cyberkey, swversion, amount,       card*   #####################################################################   Explanation:   The pr-signed-hash field is the same as the merchant-signed-hash in       the PR1 message but has a different name for historic reasons.4.3.3 CH2 - charge-card-response   Description: Return to customer from a CH1 attempt to pay via credit       card.  Indicates success/failure.   #####################################################################   Sender: MerchantApp   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: charge-card-response   merchant-ccid: ACME-012   id: myCyberCashID   transaction: 78784567   date: 1995121100500.nnn   merchant-date: 19950121100505.nnn   merchant-response-code: failure/success/etc.   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==   pr-signed-hash:    a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh    Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD   merchant-message; This is a message to display to the user from the       merchant. Can be multiple lines...  Is not secure.   opaque:  [might not be present, see explanation]    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################Eastlake, et al              Informational                     [Page 24]

RFC 1898                 CyberCash Version 0.8             February 1996   Opaque Key:   Same customer session key from CH1 passed through CM1       for ID and Transaction   #####################################################################   Opaque Section Contents (from CM.6):   server-date: 19950121100706.nnn   amount: usd 10.00   order-id: 1231-3424-234242   card*:  [from successful BC4]   response-code: failure/success/etc.   swseverity: fatal/warning   swmessage; Tells CyberApp that it is obsolete.  Display this    text to the user.  [only present if SWSeverity present]   message;          Free text of the error/success condition.          This text is to be displayed to the customer          by the CyberCash application...   #####################################################################   Signature is of the following fields: no signature   #####################################################################   Explanation:   Opaque section optional because the CH1 to the merchant can fail due       to bad order-id, date, wrong merchant-ccid, etc., etc. So the       server may not be involved at all in which case there is no       mechanism for generating a secure opaque section.  (It could even       be that merchant attempt to contact the server times out.)   If transaction makes it through server (via CM*) then       Response-Code at top level should mirror response-code to       merchant from server. (Hopefully the same as the       response-code to customer from server but the merchant can't       tell that.)   Note that there can be two messages, one from merchant and one       from the server.4.4 Merchant Credit Card Purchasing Messages   The merchant presents credit card purchases, makes adjustments, and   the like via the CM* series.  In general, the credit card cycle is   one of getting authorization for a purchase, then capturing the   purchase in a batch for clearance, then performing the clearance.  It   is also possible to void a capture (i.e., remove an item from a   batch), and process credits (returns). (Seesection 5.1.)Eastlake, et al              Informational                     [Page 25]

RFC 1898                 CyberCash Version 0.8             February 1996   Authorizations always come from an acquirer via the response to a CM1   or CM2 message. If capture is being performed by the acquirer or some   entity between the CyberCash server and the acquirer, this is done   via a CM3 or CM2 message depending on the arrangement between the   merchant and the entity doing the capture.  Returns (credits) are   handled via message CM5.  Message CM4 is provided for voiding a   capture or return before the batch is cleared.  CM6 is the message   format used for responses to all the other CM* messages.   An MM* series has also been implemented for purely merchant   originated CyberCash charges as described insection 3.4.7   Current credit card dispute resolution systems assume that the   merchant knows the card number.  Thus, to work with these systems,   special bypass messages have been set up that allow the merchant to   obtain, for a particular transaction, the information that CyberCash   otherwise goes to lengths to hide from the merchant.  See sections   3.4.8 and 3.4.9.  This makes the obtaining os such information by the   merchant an auditable event.   Many present day merchants operate in a "terminal capture" mode where   the authorizations are captured by the merchant and the merchant   later submits the settlement batch.  Messages have been defined and   are being implemented so that such merchant captured batches can be   submitted via CyberCash.4.4.1 CM1 - auth-only   Description: This message is used by the merchant to perform an       authorization operation on the credit card sent in by the       customer.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-69   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   merchant-cyberkey: CC1001   cyberkey: CC1001   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDVEastlake, et al              Informational                     [Page 26]

RFC 1898                 CyberCash Version 0.8             February 1996    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   merchant-opaque:    6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf    aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO    dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj    j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84    F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ    mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr    mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Merchant-Opaque Section Contents:   type: auth-only   order-id: 12313424234242   merchant-amount: usd 10.00   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==   pr-signed-hash:    a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh    Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   merchant-signature:    v4qZMe2d7mUXztVdC3ZPMmMgYHlBA7bhR96LSehKP15ylqR/1KwwbBAX8CEqns55UIYY    GGMwPMGoF+GDPM7GlC6fReQ5wyvV1PnETSVO9/LAyRz0zzRYuyVueOjWDlr5   #####################################################################   merchant-opaque key is generated from the CyberCash encrypting public        key identified in merchant-cyberkey.   Customer opaque section (Opaque) - see CH1.   #####################################################################   Opaque Section Contents & Signature:  (exactly as in CH1)   swversion: 0.8win   amount: usd 10.00   card*: [from successful BC4 (includes card-expiration-date,       card-number, and card-salt)]   signature:    48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK    +IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs   #####################################################################Eastlake, et al              Informational                     [Page 27]

RFC 1898                 CyberCash Version 0.8             February 1996   merchant-signature is on the following fields: merchant-ccid,       merchant-transaction, merchant-date, merchant-cyberkey, type,       order-id, merchant-amount, pr-hash, pr-signed-hash, id,       transaction, date, cyberkey   Customer Signature: see CH1   #####################################################################   Explanation:   The merchant signature ensures integrity of the majority of the       message.  validation of the customer signature ensures that the       customer opaque part was not tampered or replaced.4.4.2 CM2 - auth-capture   Description: Do authorization and actually enters charge for       clearance. Message just like CM1 except for different       type.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   [exactly the same as CM1 except   type: auth-capture   ]4.4.3 CM3 - post-auth-capture   Description: Captures a charge previously authorized. Message is       the same as CM1 except that it also has an authorization-code       field (which is also included in the signature) and the type       is different.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-012Eastlake, et al              Informational                     [Page 28]

RFC 1898                 CyberCash Version 0.8             February 1996   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   merchant-cyberkey: CC1001   cyberkey: CC1001   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   merchant-opaque:    6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf    aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO    dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj    j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84    F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ    mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr    mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Merchant-Opaque Section Contents:   type: post-auth-capture   authorization-code: a12323   order-id: 1231-3424-234242   merchant-amount: usd 10.00   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==   pr-signed-hash:    a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh    Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   merchant-signature:    vxyEF1ZHn5Rgmtms3H3t/+UB6RAvZQA1AdddjvlS0H75N1x83FyJuh8V9Ok6t4EUQQZ6    Mnptzc6phJi3Ar0s0oumELsdc8upJdXpNpJV021PGJXfDKfHP0heJIWLodXr   #####################################################################   merchant-opaque key is generated from the CyberCash encrypting public        key identified in merchant-cyberkey.   Customer opaque section (Opaque) - see CH1.   #####################################################################   Opaque Section Contents & Signature:  (exactly as in CH1)   swversion: 0.8winEastlake, et al              Informational                     [Page 29]

RFC 1898                 CyberCash Version 0.8             February 1996   amount: usd 10.00   card*: [from successful BC4 (includes card-salt, card-number,       and card-expiration)]   signature:    48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK    +IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs   #####################################################################   merchant-signature is on the following fields: merchant-ccid,       merchant-transaction, merchant-date, merchant-cyberkey, type,       authorization-code, order-id, merchant-amount, pr-hash,       pr-signed-hash, id, transaction, date, cyberkey   #####################################################################   Explanation:   The merchant signature ensures integrity of the majority of the       message validation of the customer signature ensures that the       customer opaque part was not tampered or replaced.4.4.4 CM4 - void   Description: Voids out a charge/return if received before       clearance.  Message is the same as CM1 except that it also has       a retrieval-reference-number field (which is also included in the       signature) and the type is different.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-012   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   merchant-cyberkey: CC1001   cyberkey: CC1001   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   merchant-opaque:    6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf    aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGOEastlake, et al              Informational                     [Page 30]

RFC 1898                 CyberCash Version 0.8             February 1996    dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj    j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84    F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ    mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr    mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Merchant-Opaque Section Contents:   type: void   retrieval-reference-number: 432112344321   order-id: 1231-3424-234242   merchant-amount: usd 10.00   pr-hash: WATCQuH2q17lRuoxD78YBg==   pr-signed-hash:    8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC    kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   Merchant-Signature: lkjladjslkjflsakjflkjsdljflsakjflkjsdljflsakjflkj       flsakjflkjsdljflsakjflkjsdljflsajflksdjflksdjflsdjssf=   #####################################################################   Merchant-Opaque key is generated from the CyberCash encrypting public        key identified in Merchant-CyberKey.   Customer opaque section (Opaque) - see CH1.   #####################################################################   Opaque Section Contents & Signature:  (exactly as in CH1)   swversion: 0.8win   amount: usd 10.00   card*: [from successful bc4 (includes card-salt, card-number,       and card-expiration)]   signature:    48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK    +IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs   #####################################################################   merchant-signature is on the following fields: merchant-ccid,       merchant-transaction, merchant-date, merchant-cyberkey, type,       retrieval-reference-number, order-id, merchant-amount, pr-hash,       pr-signed-hash, id, transaction, date, cyberkey   #####################################################################Eastlake, et al              Informational                     [Page 31]

RFC 1898                 CyberCash Version 0.8             February 1996   Explanation:   The merchant signature ensures integrity of the majority of the       message.  Validation of the customer signature ensures that the       customer opaque part was not tampered or replaced.4.4.5 CM5 - return   Description: Reverse a previous charge.  Really sort of a negative       charge.  Message just like CM1 except for different type.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   [exactly the same as CM1 except   type: return   ]4.4.6 CM6 - charge-action-response   Description: This receipt is given to the merchant as a receipt       for a completed charge action.  Indicates success/failure/etc.   #####################################################################   Sender: CyberServer   Receiver: MerchantApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-012   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   merchant-opaque:    6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf    aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGOEastlake, et al              Informational                     [Page 32]

RFC 1898                 CyberCash Version 0.8             February 1996    dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj    j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84    F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ    mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr    mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Merchant-Opaque Key: Session key same as that of CM1/2/3/4/5 for       same Merchant-Transaction and Merchant-CCID.   Opaque Key:  Same customer session key from CH1 passed through CM*       for ID and Transaction   #####################################################################   Merchant-Opaque Section Contents:   type: charge-action-response   server-date: 19950121100706.nnn   action-code: XXX  [per ISO 8583]   response-code: failure/success/etc.   order-id: 1231-3424-234242   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==   pr-signed-hash:    8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC    kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov   retrieval-reference-number: 432112344321   authorization-code: a12323   card-hash: 7Tm/djB05pLIw3JAyy5E7A==   {   card-prefix: nnxxxx  [Returned if merchant is not full-PAN]   }       or   {   card-number: 1234567890123456  [Returned if merchant is full-PAN]   }   expiration-date: 12/34  [always present]   merchant-swseverity: fatal/warning   merchant-swmessage; Message for merchant about out of date       protocol number in $$ start line of merchant message.   merchant-message;          Free text of the error/success condition.          This text is for the merchant from the server...   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   Opaque (Customer) contents:Eastlake, et al              Informational                     [Page 33]

RFC 1898                 CyberCash Version 0.8             February 1996   server-date: 19950121100706.nnn   amount: usd 10.00   order-id: 1231-3424-234242   card*: [from successful BC4]   response-code: failure/success/etc.   swseverity: fatal/warning   swmessage; Tells CyberApp that it is obsolete display this    text to the user.  [only present if SWSeverity present]   message;          Free text of the error/success condition.          This text is to be displayed to the customer          by the CyberCash application...   #####################################################################   Signature is of the following fields: no signature   #####################################################################   Explanation:   retrieval-reference-number is needed for voids. authorization-code       is needed for post-auth-capture.  These fields are each only       present in the CM6 if they were returned by the bank which       depends on what operation was being done.   card-prefix is first two and last four digits of card-number.   At merchant's bank's discretion the card-number or card-prefix is       returned.   card-hash is really the hash of the full card number and the salt       provided by the customer.  card-hash is needed so the merchant       can, if they wish, sort customer transactions by card without       knowing the card number.   card* is the card* fields delivered in the CM* messages being       responded to.  They appear in alphabetic order.   server-date duplicated in customer opaque area for security.   {}'s in column one just for clarity of alternatives and do not       actually appear in the message.   []ed comments appear after some fields.4.4.7 The MM* Message Series   The CM* message series above is the primary CyberCash credit card   purchase system for securely handling charges from CyberCash   customers.  However, merchants, who are authorized by their acquiring   bank to accept such charges, may also receive telephone, mail, and   over-the-counter sales.  To avoid any necessity for the merchant to   have a second parallel system to handle these charges, an MM1 through   MM6 message series is defined and has been implemented for these less   secure transactions.Eastlake, et al              Informational                     [Page 34]

RFC 1898                 CyberCash Version 0.8             February 1996   The MM* messages look very similar to the CM* series but the   "customer opaque" section is actually signed by the merchant and no   separate customer CyberCash ID or prior card binding is required.   The MM* message examples are omitted here in the interests of   brevity.4.4.8 CD1 - card-data-request   Description: Used by merchant to get card-number, etc., if       information needed by merchant to resolve a dispute.   #####################################################################   Sender: MerchantApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-69   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   merchant-cyberkey: CC1001   cyberkey: CC1001   opaque:    EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb    nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV    4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs    rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo    QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==   merchant-opaque:    6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf    aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO    dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj    j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84    F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ    mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr    mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Merchant-Opaque Section Contents:   type: card-data-request   password: xyzzy   server-date: 19950121100505.nnn  [optional]   order-id: 12313424234242   merchant-amount: usd 10.00   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==Eastlake, et al              Informational                     [Page 35]

RFC 1898                 CyberCash Version 0.8             February 1996   pr-signed-hash:    IV8gWHx1f8eCkWsCsMOE3M8mnTbQ7IBBcEmyGDAwjdbaLu5Qm/bh06OX1npe2d3Hijxy    +X8vKcVE6l6To27u7A7UmGm+po9lCUSLxgtyqyn3jWhHZpc5NZpwoTCf2pAK   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   merchant-signature:    8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC    kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov   #####################################################################   merchant-opaque key is generated from the CyberCash encrypting public        key identified in merchant-cyberkey.   Customer opaque section (Opaque) - see CH1.   #####################################################################   Opaque Section Contents & Signature:  (exactly as in CH1)   swversion: 0.8win   amount: usd 10.00   card*: [from successful BC4 (includes card-expiration-date,       card-number, and card-salt)]   signature:    48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK    +IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs   #####################################################################   merchant-signature is on the following fields: merchant-ccid,       merchant-transaction, merchant-date, merchant-cyberkey, type,       password, server-date, order-id, merchant-amount, pr-hash,       pr-signed-hash, id, transaction, date, cyberkey   Customer Signature: see CH1   #####################################################################   Explanation:   [see also CM1 explanation]   The merchant may need to know the card involved and other       information in order to resolve a disputed transaction.  This       information is all contained in the original CH1 embedded in the       CM1 for the transaction.  If the merchant saves the CM1 and other       transaction information, they can send this CD1 message to the       server.  While this reduces the pass through confidentiality of       the system, the merchant is then on record as asking for this       particular credit card number and excessive CD1's from a merchant       can be flagged.   password is an extra level of security intended to be manually enteredEastlake, et al              Informational                     [Page 36]

RFC 1898                 CyberCash Version 0.8             February 1996       at the merchant to authorize the unusual action.  Server stores a       hash of the merchant-ccid and the password.4.4.9 CD2 - card-data-response   Description: Respond to CD1 with failure or with success and card       data.   #####################################################################   Sender: CyberServer   Receiver: MerchantApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: ACME-012   merchant-transaction: 123123   merchant-date: 19950121100705.nnn   merchant-opaque:    t731/86R72ZLrqHLIf0VG6m3ybvs+dG6K705L8LFKEXgCti0NGjK83CwDsUdiso7U1JP    2Z0BClVHLmhIBY7+QXx5iCEGHy8JKC9IWyNNi2O/OOIDgLeJAkMSZYbNQrSKViY34imS    0s7Q6uDk9wV0fixjvRBuNO2B7urWWsqfkLOYDnHy0RvhyUzYxLrMaTX+/6IkyU5Z0lH3    BXYBUNV8DgitEjgLXmyWuXRDlEBN02yeZgsFRm9GmuBHfCTySm2XqnifizpmKMUa9UiH    onNx9W86fuBdcJF7CJgH5Gct2M/dx/f2VpoRkmeSmWxFrYi8wgtvddSXF9my40NZ8WZz    CEUEvQhcmruopwEeehv+bejc3fDDZ23JKrbhlZ17lSvFR14PKFsi32pXFqTO0ej9GTc5    L6c8nM3tI1qdHNCe0N5f7ASdKS0tYSxAYJLIR6MqPrXjNJEaRx7Vu1odMlkgrzGOV1fo    5w33BQHK3U2h+1e5zYBeHY3ZYG4nmylYYXIye4xpuPN4QU0dGrWZoImYE44QOwjd5ozl    xulPBjj6cpEI/9wTwR3tpkBb4ZfYirxxnoj9JUkPK9Srv9iJ   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Opaque Key: session key from CD1.   #####################################################################   Opaque Section Contents:   type: card-data-response   server-date: 19950121100706.nnn   response-code: failure/success/etc.   order-id: 1231-3424-234242   pr-hash: 7Tm/djB05pLIw3JAyy5E7A==   pr-signed-hash:    IV8gWHx1f8eCkWsCsMOE3M8mnTbQ7IBBcEmyGDAwjdbaLu5Qm/bh06OX1npe2d3Hijxy    +X8vKcVE6l6To27u7A7UmGm+po9lCUSLxgtyqyn3jWhHZpc5NZpwoTCf2pAK   card-hash: 7Tm/djB05pLIw3JAyy5E7A==   card-number: 4811123456781234   card-type: visaEastlake, et al              Informational                     [Page 37]

RFC 1898                 CyberCash Version 0.8             February 1996   card-name: John Q. Public   expiration-date: 01/99   merchant-swseverity: fatal/warning   merchant-swmessage; Message for merchant about out of date       protocol number in $$ start line of merchant message.   merchant-message;          Free text of the error/success condition.          This text is for the merchant from the server...   id: myCyberCashID   transaction: 78784567   date: 19950121100505.nnn   #####################################################################   Signature is of the following fields: no signature.   #####################################################################   Explanation:   This normally returns selected fields from the decoding of the       opaque part of a CH1 as sent to the server in a CD1.4.5 Utility and Error Messges   A number of utility, status query, and special error reporting   messages have also been found necessary in implementing the CyberCash   system.   It is desirable to be able to test connectivity, roughly synchronize   clocks, and get an initial determination of what client protocol and   software versions are accepted.  This is done via the P1 client to   server message and its P2 server to client response.   Clients need to be able to determine the status of earlier   transactions when the client or merchant has crashed during or has   suffered data loss since the transaction.  Two transaction query   messages are defined, TQ1 and TQ2.  One just queries and the other   also cancels the transaction, if it has not yet completed.  The   response to both of these messages is a TQ3 response from the server.   Since the system operates in a query response mode, there are two   cases where special error messages are needed.  If a query seems to   be of an undeterminable or unknown type, the UNK1 response error   message is sent.  If a response seems to be of an undeterminable or   unknown type or other serious error conditions occur at the client or   merchant which should be logged at the CyberCash server, the DL1 or   DL2 diagnostic log message is submitted by the client or merchant in   question respectively.Eastlake, et al              Informational                     [Page 38]

RFC 1898                 CyberCash Version 0.8             February 19964.5.1 P1 - ping   Description: Very light weight check that we have connectivity from       the customer to the server.  Does no crypto to minimize       overhead.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: ping   id: myCyberCashID  [optional]   transaction: 123123213   date: 19950121100505.nnn   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Explanation:   id optional as persona may not have been set up yet.4.5.2 P2 - ping-response   Description: Response to the P1 light weight ping.  Does no       crypto to minimize overhead.   #####################################################################   Sender: CyberServer   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: ping-response   id: myCyberCashID  [if present in P1]   transaction: 12312313   date: 19950121100505.nnn   server-date: 19950121100506.nnn   swseverity: fatal/warning  [absent if ok]   swmessage; Tells CyberApp that it is using an obsolete protocol.        Display this text to the user.  [only present if SWSeverity       present]   response-code: success/failure/etc.   message;          Free text of the error/success condition.          This text is to be displayed to the senderEastlake, et al              Informational                     [Page 39]

RFC 1898                 CyberCash Version 0.8             February 1996          by their CyberCash application...   supported-versions: 08.win, 0.81win, 0.8mac   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Explanation:   swversion does not appear in P1 for security reasons so       swseverity and swmessage appear only if the server can tell       that things are old from the $$ header protocol version.   supported-versions lets client know as soon as possible what       versions are supported and, by implication, which are not. Does       not compromise security by having client say what version it       is.4.5.3 TQ1 - transaction-query   Description: Client query to server for Transaction status.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   id: MyCyberCashID   date: 19950121100505.nnn   transaction: 12312314   cyberkey: CC1001   opaque:    VFaztHuj757Jrv+JxZFsHORy/zgkrxhBCu9cPdE04c1NnXzVlGOHygpSl+UGbUvnhkYl    21QQaHkaE3geccRk03cqFYoLNRCclImcsyeIZCgVt+2dJTj1V+E7R7ePQtCj+0gY42+V    L5BWhVtmDQFyg1DdJ6n3S/er6ZuObAjpcAogG+T1Na5dJmrTA1wRMiYVkqhXi2KMYdur    3U47P8ZGUza7W0MST3DgvviN0kVhtmHEnm515mo6NTQdfdxw9WZpy6vMqrBGk2nTgi2c    bnf+muO0+kiNPXVvEzRrO8o=   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: generated from CyberCash encryption key identified in       CyberKey   #####################################################################   Opaque Section Contents:   type: transaction-query   swversion: 0.8win   begin-transaction: 1234Eastlake, et al              Informational                     [Page 40]

RFC 1898                 CyberCash Version 0.8             February 1996   end-transaction: 4321   signature:    jJfFsKvOxLaV87gxu7lIPet3wIDwh1H2F61reYC9jmUrS6WAtUVFG9aCNuTEBoMixF0X    vD5oPfyheJRIlnL6i0c4o/bfyO3edKAacmWjTmKt6/4y9p3qgvKkSX8r9aym   #####################################################################   signature is of the following fields: id, date, transaction,       cyberkey, type, swversion, begin-transaction,       end-transaction   #####################################################################   Explanation:   This is a client status query of a previous transaction or       transactions.   begin-transaction and end-transaction can be the same.4.5.4 TQ2 - transaction-cancel   Description: Client query to server for Transaction       cancellation/status.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   id: MyCyberCashID   date: 19950121100505.nnn   transaction: 12312314   cyberkey: CC1001   opaque:    VFaztHuj757Jrv+JxZFsHORy/zgkrxhBCu9cPdE04c1NnXzVlGOHygpSl+UGbUvnhkYl    21QQaHkaE3geccRk03cqFYoLNRCclImcsyeIZCgVt+2dJTj1V+E7R7ePQtCj+0gY42+V    L5BWhVtmDQFyg1DdJ6n3S/er6ZuObAjpcAogG+T1Na5dJmrTA1wRMiYVkqhXi2KMYdur    3U47P8ZGUza7W0MST3DgvviN0kVhtmHEnm515mo6NTQdfdxw9WZpy6vMqrBGk2nTgi2c    bnf+muO0+kiNPXVvEzRrO8o=   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: generated from CyberCash encryption key identified in       CyberKey   #####################################################################   Opaque Section Contents:Eastlake, et al              Informational                     [Page 41]

RFC 1898                 CyberCash Version 0.8             February 1996   type: transaction-cancel   swversion: 0.8win   begin-transaction: 1234   end-transaction: 4321   signature:    kD7DEav2uLQIYMtP9gbhYaBUpB2a5whNwnK2eXbbyTCf56F6dl3DIVf7D8Z4WxbY2YZn    ByRIKeqlhmss7fbdnBiDYmKfOuc+I4bi/Oslml5riaciQhTd2JdHG+PCcHwZ   #####################################################################   signature is of the following fields: id, date, transaction,       cyberkey, type, swversion, begin-transaction, end-transaction   #####################################################################   Explanation:   This is a client attempt to cancel a previous transaction or       transactions.   begin-transaction and end-transaction can be the same.   The transaction-cancel transaction (TQ.2) is defined between the   client and the server.  This transaction permits the client to   query the status of an operation and to stop the operation from   occurring if it has not already occurred.4.5.5 TQ3 - transaction-response   Description: Reports generated by a TQ1 or TQ2   #####################################################################   Sender: CyberServer   Receiver: CyberApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   id: mycybercashid   date: 19950121100505.nnn   transaction: 12312314   server-date: 19950121100505.nnn   opaque:    eFXRL+H0J5q318M21wRdtcbhu9WCyLysQkeF9oIcjtbstymx343bbt0EAtU1gcJaUKJZ    3skgvwrhcxU4bFcE68OPlUXAvLq10I3MczPYPsiGrsU0K4bZtQvDZmn727QQAfONBm5s    s1yjIha+Fj481BJQs0CTYc3ju90lAjCYgirXtnnR6yJXoDO75b7UjthvHSnrTWVZvktX    PvTuUCYzbXSFoYvwFM3Y+yHqSHlmWutYKQpYze8zbUSDQfmwTCJyw3aY2JasZ+xMP/CD    JWbCA+gCLBYCnvzM/ExKTZTFD3xr5JBfNbV4p6CiK6lsfRFD7maAK6TSVnWjwCEJNpOv    fyllfWD04fT7LINQcjJiQK1Pk/912Tk6Q35eRaQZorwv2hnY/7By2OkPyFdAqFL+D0H6    TqzxmdEjEFKxi/PPT1+Cs/Nszy8wZzaGg8iWATfARY6stl+02dDhwOoFXSBNvchlVrcI    IlvhumSIQs29Pntj3DbkYo4IEmmN/qi1vnzld22q7lA1q/CQakyc7jlQUFISx76buqwyEastlake, et al              Informational                     [Page 42]

RFC 1898                 CyberCash Version 0.8             February 1996    35XiC9Yn8flE4Va14UxMf2RCR1B/XoV6AEd64KwPeCYyOYvwbRcYpRMBXFLyYgWM+ME1    +yp7c66SrCBhW4Q8AJYQ+5j5uyO7uKyyq7OhrV0IMpRDPjiQXZMooLZOifJPmpvJ66hC    VZuWMuA6LR+TJzWUm4sUP9Zb6zMQShedUyOPrtw1vkJXU1vZ5aI8OJAgUcLEitcD+dsY    Df4CzA00fC10POkJ58HZB/pSBfUrHAa+IqMHyZkV/HBi9TjTwmktJi+8T9orXS0jSvor    dMTGWn0ifETy2VXt   $$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$   #####################################################################   Opaque Key: Session key from TQ1/TQ2 with same Transaction and ID.   #####################################################################   Opaque Section Contents:   type: transaction-response   response-code: success/failure/etc.   message; general free form text message from server to       customer....   swseverity: fatal/warning   swmessage; Message indicating that CyberApp software is obsolete.       May be multiple lines.   report-fee: usd 0.15  [if non-zero]   transaction-1: old-transaction-number   transaction-status-1: success/failure/pending/cancelled/etc.   server-date-1: 19951212125959.nnn   date-1: 19950121100505.nnn   type-1: auth-only/etc.   #####################################################################   Signature is of the following fields:  no signature   #####################################################################   Explanation:   Report-fee is the notification that this report cost a fee and is       only present if there is a fee.   There can be multiple transaction for the same transaction number as       there could have been a auth, post-auth-capture, void, etc.   Terms       "original transaction" refers to the payment or other transaction   that is being queried or canceled.          Note: this transaction may not actually reside at the server.       "request" refers to the requesting TQ.2 or TQ.1 message   id: id from the request message   date: date from the request message   transaction: transaction from the request messageEastlake, et al              Informational                     [Page 43]

RFC 1898                 CyberCash Version 0.8             February 1996   server-date: current date/time   type: transaction-response   response-code: response code for request message, can be one of:       "success" means the request message was processed.  Does not imply       query or cancellation status of the request.       "failure-hard" means that the request message was not processed       due to being ill-formed or otherwise inoperable.       "failure-swversion" means that the request message was not       processed due to software revision problems.   message: the message applies only to the TQ transaction, not to the       status of the transactions being queried or canceled.  The       message is provided according to the response-code as: "success"       - message is omitted. "failure-hard" - use standard hard failure       message. "failure-swversion" - use standard swversion message for       fatal   swseverity: applies to request message   swmessage: applies to request message    -- per query/cancel fields ('N' is a series from 1 to N) --   transaction-N: transaction number of original transaction, or if       the original transaction is not present in server the transaction       number that the query / cancel request refers to   transaction-status-N: status of original transaction, may be one of:       "success" the original transaction was successfully processed.       If request was TQ.2, cancellation is not performed.       "failure" the original transaction was not successfully processed.        If request was TQ.2, cancellation is not performed (however,       there is nothing to cancel, so it's all the same to the customer       app).       "pending" the original transaction is still being processed and       final disposition is not known.   "canceled" the original transaction has been canceled by the server.       Later arrival of the original transaction will not be processed,       but will be returned with a "failure-canceled" returned.   server-date-1: server-date field from original transaction or       omitted if original transaction is not present in the server"   date-1: date field from original transaction or omitted if original       transaction is not present in the server"   type-1: type field from original transaction or omitted if original       transaction is not present in the server"4.5.6 UNK1 - unknown-error   Description: This is the response sent when the request is so       bad off you can't determine what type it is or the type is       unknown to you.  Sent from Merchant to Client or from Server       to Merchant or from Server to Client.Eastlake, et al              Informational                     [Page 44]

RFC 1898                 CyberCash Version 0.8             February 1996   #####################################################################   Sender: MerchantApp or CyberServer   Receiver: CyberApp or MerchantApp   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   type: unknown-error   unknown-error-message:       Text message of error condition to display to user.  (CyberCash       wrapper not found, wrapper integrity check fails, unknown protocol       version specified, unknown type specified, etc.)   {   server-date: 19950121100506.nnn  [if sent by server]   }       or   {   merchant-date: 19950121100506.nnn  [if sent by merchant]   }   x-id: mycybercashID   x-transaction: 123123213   x-date: 19950121100505.nnn   x-cyberkey: CC1001   x-opaque:    2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G    9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7    TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw    5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX    GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm    lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy    Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW   $$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$   #####################################################################   Opaque Key: see explanation   #####################################################################   Opaque Section Contents: see explanation   #####################################################################   Signature is of the following fields: see explanation   #####################################################################   Explanation:   This message is sent as a response when you can't find or understand       even the type of a message to you.  It will always have type and       unknown-error-message fields at the beginning.  Any fields from       the request that are parseable are simply echoed back in the UNK1Eastlake, et al              Informational                     [Page 45]

RFC 1898                 CyberCash Version 0.8             February 1996       message with "x-" prefixed to it.  Thus, if an x-opaque appears,       it was whatever the opaque was in the original request, etc.  If       you can decrypt the opaque section, you don't want to put the       results here in the clear!   {}'s in the first column are to group alternatives only and do not       appear in the message.   Since the customer originates exchanges with merchant and server       and merchant originates exchanges with server, this message       will only be emitted from the merchant to the customer or the       server to the customer or merchant. It should generally just       be logged for debugging purposes.   You may need to watch out for denial of service via forged or       replayed UNK1 messages.4.5.7 DL1 - diagnostic-log   Description: Client diagnostic log of bad message from either       merchant or server.   #####################################################################   Sender: CyberApp   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   id: MyCyberCashID   date: 19950121100505.nnn   transaction: 1234   cyberkey: CC1001   opaque:    2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G    9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7    TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw    5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX    GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm    lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy    Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################   Opaque Key: generated from CyberCash encryption key identified in       CyberKey   #####################################################################   Opaque Section Contents:Eastlake, et al              Informational                     [Page 46]

RFC 1898                 CyberCash Version 0.8             February 1996   type: diagnostic-log   message: incorrect order-id   swversion: 0.8win   x-type: original-message-type   x-transaction: original-transaction-number   x-opaque: [if can't decrypt]    9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3    5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw   #####################################################################   Explanation:   Client application does not expect a response for this message. The       decrypted original message will be in the opaque section unless       decryption fails. If decryption fails then un-decrypted opaque       in the original will be sent.   This message will be sent to a different script or socket or host       than normal messages so that it will just be absorbed and never       generate an UNK1 response or anything, even if this message       itself is screwed up.4.5.8 DL2 - merchant-diagnostic-log   Description: Merchant diagnostic log of bad message from  server.   #####################################################################   Sender: CyberMerchant   Receiver: CyberServer   #####################################################################   Sample Message:   $$-CyberCash-0.8-$$   merchant-ccid: MyCyberCashID   merchant-transaction: 1234   merchant-date: 19950121100505.nnn   merchant-cyberkey: CC1001   merchant-opaque:    2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G    9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7    TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw    5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX    GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm    lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy    Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW   $$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$   #####################################################################Eastlake, et al              Informational                     [Page 47]

RFC 1898                 CyberCash Version 0.8             February 1996   Opaque Key: generated from CyberCash encryption key identified in       CyberKey   #####################################################################   Opaque Section Contents:   type: merchant-diagnostic-log   server-date:  19950121100505.nnn  [optional]   message: incorrect order-id   x-type: original-message-type   x-transaction: original-transaction-number   x-opaque: [if can't decrypt]    9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3    5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw   #####################################################################   Explanation:   Merchant application does not expect a response for this message. The       decrypted original message will be in the opaque section unless       decryption fails. If decryption fails then un-decrypted message       will be sent.   This message will be sent to a different script or socket or host       than normal messages so that it will just be absorbed and never       generate an UNK1 response or anything even if this message       itself is screwed up.4.6 Table of Messages Described   The following 31 messages are described in this document.   C = Customer App, M = Merchant App, S = CyberCash Server   FLOW  SECTION  NAME   C->S   4.2.1   BC.1 bind-credit-card   S->C   4.2.2   BC.4 bind-credit-card-response   C->M   4.3.2   CH.1 credit-card-payment   M->C   4.3.3   CH.2 credit-card-response   M->S   4.4.8   CD.1 card-data-request   S->M   4.4.9   CD.2 card-data-response   M->S   4.4.1   CM.1 auth-only   M->S   4.4.2   CM.2 auth-capture   M->S   4.4.3   CM.3 post-auth-captureEastlake, et al              Informational                     [Page 48]

RFC 1898                 CyberCash Version 0.8             February 1996   M->S   4.4.4   CM.4 void   M->S   4.4.5   CM.5 return   S->M   4.4.6   CM.6 charge-action-response   C->S   4.5.7   DL.1 diagnostic-log   M->S   4.5.7   DL.2 merchant-diagnostic-log   C->S   4.1.3   GA.1 get-application   S->C   4.1.4   GA.2 get-application-response   M->S   4.4.7   MM.1 merchant-auth-only   M->S   4.4.7   MM.2 merchant-auth-capture   M->S   4.4.7   MM.3 merchant-post-auth-capture   M->S   4.4.7   MM.4 merchant-void   M->S   4.4.7   MM.5 merchant-return   S->M   4.4.7   MM.6 merchant-charge-action-response   C->S   4.5.1   P.1 ping   S->C   4.5.2   P.2 ping-response   M->C   4.3.1   PR.1 payment-request   C->S   4.1.1   R.1 registration   S->C   4.1.2   R.2 registration-response   C->S   4.5.3   TQ.1 transaction-query   C->S   4.5.4   TQ.2 transaction-cancel   S->C   4.5.5   TQ.3 transaction-response   S->C, S->M, M->C          4.5.6   UNK.1 unknown-error5. Future Development   CyberCash is extending the facilities available through the CyberCash   system.  We are committed to implementing a full cash system,   including efficient transfer of small amounts of money, the extension   of the credit card system to handle terminal capture and clearances,   and other improvements.5.1 The Credit Card Authorization/Clearance Process   There are six steps in credit card processing as listed below.  The   first four are always involved if a transacation is completed.  The   fifth and sixth are optional.   (1) authorization: merchant contacts their acquiring back which       normally contacts the card issung bank and returns to the       merchant an approval/guarantee or a disapproval.  ThisEastlake, et al              Informational                     [Page 49]

RFC 1898                 CyberCash Version 0.8             February 1996       temporarily decreases the available credit on the card.   (2) capture: the charge information for a purchase is entered by       the merchant into a batch.   (3) clearance: a batch of items is processed.  This actually causes       the items in the batch to appear on credit card statements as       sent by the issuing bank to its carholders.   (4) settlement: the actual interbank transfer of net funds.   (5) void: the merchant undoes step 2 (or 6) and causes a charge (or       credit) to be removed from a batch.  Must be done before the       batch is processed.   (6) credit: the merchant causes a "negative charge" or credit to be       entered into a batch.  This will appear on the cardholders       statement.   The fourth step, settlement, is entirely within the banking community   and does not concern us here.  CyberCash 0.8 provides messages to do   1, 1&2, 2, 5, and 6.  This is adequate for credit card processor   systems where the batch is accumulated at the bank or between the   bank and the merchant.  CyberCash 0.8 supports such "host capture"   systems.  Other credit card processor systems require the merchant to   accumulate the batch.  Such systems are frequently referred to as   "terminal capture".  This makes actions 2, 5, and 6 internal to the   merchant but requires messages to perform action 3.  Such batch   clearance messages will be included in future versions of the   CyberCash merchant and server software.5.2 Lessons Learned   The continuing rapid development of the CyberCash system is an   interesting experience.  The system must deal with many existing   browsers and legacy banking systems.  Existing credit card processors   that convey transactions to acquiring banks have complex and varied   interfaces.  The sophistication of security attacks on the Internet   is growing rapidly.   In the face of such a rapidly changing environment, it was essential   to adopt a general message framework so that messages and fields   could be added as they were found necessary.  Any attempt to reduce   the system to a small number of perfectly opimized messages in   advance would have doomed the system to failure.  (As of mid-October   1995, the total number of CyberCash messages defined, including those   planned for cash and microcash, enhancements to the credit card   system, and some old messages being phased out in favor of improved   replacements, is just over a hundred.)   Flexible operational and error handing facilities are also, as usual,   the bulk of the system.  Version numbering and tracking has proved to   be quite important and merchant versioning is being added.Eastlake, et al              Informational                     [Page 50]

RFC 1898                 CyberCash Version 0.8             February 1996   Use of text for messages has proven very beneficial.  This makes it   possible to easily deal with messages using common everyday tools   such as text editors and spead sheets.  Use of binary TLV (type,   length, value) encoding or the like is certainly possible but imposes   a significantly higher level of complexity on every tool that has to   deal with the messages.   Encryption and decryption impose some difficulties in development.   Any confusion about decryption keys or algorithms will render   encrypted material meaningless and tools are needed to provide   decyrption for debugging outside of normal program operation.  But   this pales compared with the stringencies imposed by signatures.  All   parts of the system must have absolutely identical ideas as to the   exact bit patterns to be hashed or signed and their exact order.   Seemingly trivial differences in capitalization, punctuation,   framing, order, or the like, in addition to any disagreement about   keys or algorithms, will lead to frustrating failures of signatures   to match.  Passing signatures through an intermediate system and   checking them at a third system, as is done when a customer's   signature is passed through a merchant and checked at the CyberCash   server, compounds the problem.6. Security Considerations   The CyberCash Version 0.8 Credit Card system provides substantial   protection to payment messages as described above in sections1.2,   2.2.4, and 2.2.5.  However, it provides no privacy to the shopping   interaction which is essentially outside of its purview.  It also   provides no protection against dishonest merchants other than those   normally available with credit card purchases.  Care must be taken to   avoid loss of control of the machines on which parts of this system   runs or security may be compromised.   Current credit card dispute  resolution  systems  require  deliberate   bypasses be implemented for some of the security normally established   by CyberCash as described insection 3.4.References   [ISO 4217] - Codes for the representation of currencies and funds   [ISO 8583] - Financial transaction card originated messages -   Interchange message specifications, 1993-12-15.   [RFC 822] - Crocker, D., "Standard for the format of ARPA Internet   text messages", STD 11,RFC 822, UDEL, August 1982.Eastlake, et al              Informational                     [Page 51]

RFC 1898                 CyberCash Version 0.8             February 1996   [RFC 1521] - Borenstein, N., and N. Freed, "MIME (Multipurpose   Internet Mail Extensions) Part One: Mechanisms for Specifying and   Describing the Format of Internet Message Bodies",RFC 1521,   Bellcore, Innosoft, September 1993.   [RFC 1766] - Alvestrand, H., "Tags for the Identification of   Languages", UNINETT, March 1995.Authors' Addresses   Donald E. Eastlake 3rd   CyberCash, Inc.   318 Acton Street   Carlisle, MA 01741 USA   Phone:   +1 508 287 4877   EMail:   dee@cybercash.com   Brian Boesch   CyberCash, Inc.   2100 Reston Parkway, Suite 430   Reston, VA 22091 USA   Phone:   +1 703-620-4200   EMail:   boesch@cybercash.com   Steve Crocker   CyberCash, Inc.   2100 Reston Parkway, Suite 430   Reston, VA 22091 USA   Phone:   +1 703-620-4200   EMail:   crocker@cybercash.com   Magdalena Yesil   CyberCash, Inc.   555 Twin Dolphin Drive, Suite 570   Redwood City, CA 94065 USA   Phone:   +1 415-594-0800   EMail:   magdalen@cybercash.comEastlake, et al              Informational                     [Page 52]