Outdated egg!

This is an egg for CHICKEN 4, the unsupported old release. You're almost certainly looking for the CHICKEN 5 version of this egg, if it exists.

If it does not exist, there may be equivalent functionality provided by another egg; have a look at the egg index. Otherwise, please consider porting this egg to the current version of CHICKEN.


  1. Outdated egg!
  2. siphash
  3. Description
  4. Requirements
  5. API
  6. Examples
  7. Author
  8. License


A Scheme implementation of the SipHash family of hash functions.

SipHash is a cryptographically strong family of hash functions designed by Jean-Philippe Aumasson and Daniel J. Bernstein.

The source for this extension is available here.



Three functions are provided:

[procedure] (make-siphash c d) => procedure

make-siphash constructs a hashing function.

It takes two positive integer arguments c and d and returns a hashing procedure with that many compression and finalization rounds, respectively.

The returned procedure's signature matches those of siphash-2-4 and siphash-4-8.

[procedure] (siphash-2-4 key) => (procedure message) => integer
[procedure] (siphash-2-4 key message) => integer
[procedure] (siphash-4-8 key) => (procedure message) => integer
[procedure] (siphash-4-8 key message) => integer

siphash-2-4 and siphash-4-8 are predefined hashing procedures.

Each takes one or two SRFI-4 u8vector arguments, the key and message to hash, and returns a positive integer. key should 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.


> (define string->u8vector (compose blob->u8vector string->blob))
> (define key (u8vector 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15))
> (define msg (string->u8vector "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)
    "In Hertford, Hereford and Hampshire, hurricanes hardly ever happen."))
; => 9275736844991428064


Evan Hanson


3-Clause BSD