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DISCoHAsH, also known asBEBB4185 or justdiscohash, is a straightforward and high-performance hash function that combines simplicity with impressive performance. While there are several great high-speed hash functions available, DISCoHAsH stands out for its elementary implementation, not relying on architecture-specific optimizations, and still delivering commendable speed and quality. It’s not the fastest nor the best in quality, but its simplicity and portability make it an excellent choice for various applications.

DISCoHAsH has passed all the tests in SMHasher and clocks in at 8-10GB/s, depending on hardware. It's one of the fastest hash functions as perSUPERCOP ECRYPT benchmark.

This repository features a portable, serial implementation in C++. Moreover, an unofficial Go port is availablehere, and there's also a JavaScript version.

• 🚀 High-speed 64-bit hash function.
• 🎛 Flexible output sizes ranging from 64 to 256 bits.
• 🛠 Remarkably simple and portable implementation.
• 🧪 Successfully passes all SMHasher tests.
• 🌐 Implemented in C++ with ports to JavaScript and Go.
• 🔧 Includes a simple Command Line Interface (CLI) app for hashing files or standard input from the command line.
• 🔄 Efficient mixing function utilizing multiplications by 64-bit primes, bit rotation, and XOR.

Doing elementary cryptanalysis on DISCoHAsH with ChatGPT assisting.

We extend an open invitation to the cryptographic community for cryptanalysis of DISCoHAsH, particularly focusing on the 128-bit variant. This is an excellent opportunity for cryptographers and security enthusiasts to evaluate the strength of Discohash.

If you are able to make a breakthrough or conduct significant analysis, please submit your results as Pull Requests, updating the README with a link to your analysis. Alternatively, you cancontact Cris (me, the author) directly.

Important Note: To focus on the 128-bit variants, you must modify the source files in C/C++.

The 128-bit to 128-bit core mixing function is succinctly presented below:

mix(constintA) {constintB=A+1;ds[A] *=P;ds[A]=rot(ds[A],23);ds[A] *=Q;ds[B] ^=ds[A];ds[B] *=P;ds[B]=rot(ds[B],23);ds[B] *=Q;  }

This function makes use of two 64-bit primes,P andQ, bit rotation, and XOR operations. The primesP andQ are defined as:

• P = 0xFFFFFFFFFFFFFFFF - 58 (largest 64-bit prime)
• Q = 13166748625691186689 (random prime)

Interestingly, P and Q have the interesting property thatP - Q = P ^ Q (their difference equals their XOR).

Discohash's standard version employs an internal

state of 256 bits, with the mixing function operating across it. The standard digest size is 64 bits, but you can modify it to produce 128 bits or higher for cryptographic security.

The output has the same format asshasum -a 256 myfile.txt

cd src./build.sh./bin/discosum myfile.txt>... 256-bithash value as hex ... myfile.txt

Install using npm:

npm i --save bebb4185

Use in Node.JS:

import{discohash}from'bebb4185'

Usage:

consthash=discohash(string_or_typed_array_key,optional_seed);

Note: The JavaScript implementation is ~500x slower than the C++ implementation due to the use of BigInts.

For Golang enthusiasts, an unofficial port to Go is availablehere.

This hash when applied iteratively to its own hex output (a chain; with the initial link being a 32-byte input of all zeroes in binary not hex), generates a 2-byte zero prefix after 8,715 iterations, and a 3-byte zero prefix after 8,670,480 iterations:

8670467: 630f74d376ad3dc21aef6b2b6522ba385153fc9bad730e045153fc9bad730e048670468: 8d3b99e94dd7b62e62b3958909d7802e0e9ddfdee75087a50e9ddfdee75087a58670469: 6026eb0fce14e4835f14c0efa9e88363b9ab4053a1ee8b6bb9ab4053a1ee8b6b8670470: f83dd7560d0b6271e7bd174582ca5d718801aefeeebf46f48801aefeeebf46f48670471: aef29abc0eda55952ee2183be8159551a7f4aca19bad85e2a7f4aca19bad85e28670472: e6160e8f87accfb9d515ec6f7790ac397ba822756d23b8d07ba822756d23b8d08670473: 99803a19074ebd91557fb596f820398d709bbb32784d3896709bbb32784d38968670474: 199d695ee4f4ecce0459161c1ac2cc2e9482b241e7fb8ec29482b241e7fb8ec28670475: 82b400dd268da3ee6233fcdd160d1bee5defcdb070c223cc5defcdb070c223cc8670476: 67c5760121db846b07c461fe99d87363d6ec497d53aee544d6ec497d53aee5448670477: 482ea819bb8b7996b7a91615bb40715092aa897234e15d2e92aa897234e15d2e8670478: 10b44e30f2eea61fccb431cef28e981f7dca7cc0b91748e57dca7cc0b91748e58670479: 0421da4bddc42996e3d821231a33c16073ba1d3140a2b05973ba1d3140a2b0598670480: 0000009d947ee793ffffff5114791753e4f60afe9a96cf43e4f60afe9a96cf43Found hash with first three bytes 0x00 after 8670480 iterations.

These values are inline with when on average you would expect to land on some particular criterion (~ 1/2 * 2**b) where b is the bit length of the criterion, from a random sequence. So for two bytes (b = 16) you'd expect it around 32768 (with 8,715 being roughly 0.27x) and for 3 bytes (b = 24) you'd expect it around 8388608 (with 8670480 being roughly 1.03x).

For detailed information and updates, please visit theDiscohash GitHub repository. Your contributions and feedback are always welcome!