AH1 is a family of non-cryptographic hash functions. It includes a 128-bit and a 256-bit hashing algorithm. The 256-bit variant was a later addition. The original version only had a 128-bit verision. Have been tested against dictionaries as large as one million words with zero detected collisions. It has an above average Hamming score and even beats Murmur3 hashing algorithm in some edge cases. This makes it a decent, if not good, hashing algorithm to be used in hash tables, validate data integrity and generate file digests.

Despite speed not being a primary motivation, the hash function has kept up pretty good with speed too. It is still slower than many standard hashing algorithms like CityHash, but more than usable for general-purpose use cases and small strings.

Installation

sudo make
make repl   # build repl tool
make tests  # run tests

To use the function, include AH1.h in your source file. It's most probably in the /usr/include directory. Otherwise, to see example usage, see repl.c and digest.c.

Copyright

The MIT License (MIT)

Copyright (c) 2025 Abhigyan nourr@duck.com