Reference implementation of SipHash, a family of pseudorandom functions optimized for speed on short messages.
SipHash was designed as a mitigation to hash-flooding DoS attacks. It is now used in the hash tables implementation of Python, Ruby, Perl 5, etc.
will build tests for
- SipHash-2-4, the default version of SipHash returning 64-bit tags
- SipHash-2-4 with doubled tag size, i.e. 128-bit tags
- HalfSipHash-2-4, a version of SipHash working with 32-bit words and returning 32-bit tags by default
- HalfSipHash-2-4 with doubled tag size, i.e. 64-bit tags
verifies 64 test vectors, and
does the same and prints intermediate values.
The code can be adapted to implement SipHash-c-d, the version of SipHash
with c compression rounds and d finalization rounds, by defining
dROUNDS when compiling. This can be done with
-D command line arguments
to many compilers such as below.
gcc -Wall --std=c99 -DcROUNDS=2 -DdROUNDS=4 siphash.c halfsiphash.c test.c -o test
makefile also takes c and d rounds values as parameters.
make cROUNDS=2 dROUNDS=4
Obviously, if the number of rounds is modified then the test vectors won't verify.
The SipHash reference code is released under CC0 license, a public domain-like licence.
We aren't aware of any patents or patent applications relevant to SipHash, and we aren't planning to apply for any.
The SipHash page includes
- a list of third-party implementations and modules
- a list of projects using SipHash
- references to cryptanalysis results