siphash ======= A Scheme implementation of the SipHash family of hash functions. Description ----------- [SipHash][] is a cryptographically strong family of hash functions designed by Jean-Philippe Aumasson and Daniel J. Bernstein. This library provides an implementation of these functions for R7RS and [CHICKEN Scheme][]. [SipHash]: http://131002.net/siphash [CHICKEN Scheme]: http://call-cc.org/ Installation ------------ To install for CHICKEN Scheme, just run `chicken-install`: $ git clone http://git.foldling.org/siphash.git $ cd siphash $ chicken-install -test On other R7RS Schemes, this project's `src/` directory should be added or moved onto the system's load path. Usage ----- The `(foldling siphash)` library provides three functions: * `make-siphash` * `siphash-2-4` * `siphash-4-8` `make-siphash` constructs a hashing function. It takes two positive integer arguments `c` and `d` and returns a hashing procedure of that number of compression and finalization rounds, respectively. (make-siphash c d) => (procedure key) => (procedure message) => integer `siphash-2-4` and `siphash-4-8` are predefined hashing procedures. Each takes one or two arguments, the key and message to hash, and returns a positive integer. `key` and `message` are bytevectors, and `key` must have a length of 16 while `message` may be any length. If `message` isn't given, a prekeyed hashing function is returned. The SipHash specification recommends SipHash-2-4 for performance and SipHash-4-8 for cryptographic security. (siphash-2-4 key) => (procedure message) => integer (siphash-2-4 key message) => integer (siphash-4-8 key) => (procedure message) => integer (siphash-4-8 key message) => integer Examples -------- > (import (foldling siphash)) > (define key (bytevector 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15)) > (define msg (string->utf8 "The rain in Spain falls mainly on the plain.")) > (siphash-2-4 key msg) ; => 8751579407287093977 > ((siphash-4-8 key) msg) ; => 13472556437817646137 > ((make-siphash 8 16) key (string->utf8 "In Hertford, Hereford and Hampshire, hurricanes hardly ever happen.")) ; => 9275736844991428064 Author ------ Evan Hanson License ------- Copyright (c) 2013-2018, Evan Hanson under a BSD-style license. See LICENSE for full license information.