Rijndael is free for any use public or private, commercial or non-commercial.[1] The authors of Rijndael used to provide a homepage[2] for the algorithm. Care should be taken when implementing AES in software, in particular around side-channel attacks.
The algorithm operates on plaintext blocks of 16 bytes. Encryption of shorter blocks is possible only bypadding the source bytes, usually withnull bytes. This can be accomplished via several methods, the simplest of which assumes that the final byte of the cipher identifies the number of null bytes of padding added.
Careful choice must be made in selecting themode of operation of the cipher. The simplest mode encrypts and decrypts each 128-bit block separately. In this mode, calledelectronic code book (ECB), blocks that are identical will be encrypted identically; this is entirely insecure. It makes some of the plaintext structure visible in the ciphertext. Selecting other modes, such as using a sequential counter over the block prior to encryption (i.e., CTR mode) and removing it after decryption avoids this problem. Another mode,Cipher Block Chaining (CBC) is one of the most commonly used modes of AES due to its use in TLS. CBC uses a random initialization vector (IV) to ensure that distinct ciphertexts are produced even when the same plaintext is encoded multiple times. The IV can be transmitted in the clear without jeopardizing security. A common practice is to prepend the 16 byte IV to the ciphertext, which gives the decrypter easy access to the IV. Care must be taken to use a new IV for every encryption operation, since otherwise an attacker can recover plaintext.
Current list of FIPS 197 validated cryptographic modules (hosted by NIST)
Current list of FIPS 140 validated cryptographic modules with validated AES implementations (hosted by NIST) – Most of these involve a commercial implementation of AES algorithms. Look for "FIPS-approved algorithms" entry in the "Level / Description" column followed by "AES" and then a specific certificate number.
Microsoft CryptoAPI usesCryptographic Service Providers to offer encryption implementations. The Microsoft AES Cryptographic Provider was introduced in Windows XP and can be used with any version of the Microsoft CryptoAPI.[3]
tiny-AES-c Small portable AES128/192/256 in C (suitable for embedded systems)
AES-256 A byte-oriented portable AES-256 implementation in C
LibTomCrypt is a modular and portable cryptographic toolkit that provides developers with well known published block ciphers, one-way hash functions, chaining modes, pseudo-random number generators, public key cryptography and other routines.
As of version 3.5 of the.NET Framework, the System.Security.Cryptography namespace contains both a fully managed implementation of AES and a managed wrapper around theCAPI AES implementation.
Away RJN Cryptography[5] uses Rijndael Algorithm (NIST AES) 256-bit Data Blocks, Cipher Key and CTR (Counter Mode) for any and all Document or picture encryption in Windows only.
