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SipHash: a fast short-input PRF

This is a pure Ada implementation of the SipHash PRF.

It is based on the original paper and tested against the test values provided in the paper and in the reference C implementation.

SipHash was designed by Jean-Philippe Aumasson and Daniel J. Bernstein.

Description

From the official website:

SipHash is a family of pseudorandom functions (a.k.a. keyed hash functions) optimized for speed on short messages.

Target applications include network traffic authentication and defense against hash-flooding DoS attacks.

SipHash is secure, fast, and simple (for real):

SipHash is simpler and faster than previous cryptographic algorithms (e.g. MACs based on universal hashing)
SipHash is competitive in performance with insecure non-cryptographic algorithms (e.g. MurmurHash)

We propose that hash tables switch to SipHash as a hash function. Users of SipHash already include FreeBSD, OpenDNS, Perl 5, Ruby, or Rust.

Usage

Block interface:

with SipHash.PRF;
[…]
package SipHash24 is new SipHash.PRF(Nb_Compression_Rounds  => 2,
                                     Nb_Finalization_Rounds => 4);
[…]
Output := SipHash24.Hash(Input, Key);

Streaming interface:

with SipHash.PRF;
[…]
package SipHash48 is new SipHash.PRF(Nb_Compression_Rounds  => 4,
                                     Nb_Finalization_Rounds => 8);
[…]
-- Initialization with the 128-bit secret key.
Hash : SipHash48.Object := SipHash48.Initialize(Key);
[…]
-- Processing of each byte of the input.
for I in Input'Range loop
   SipHash48.Update(Hash, Input(I));
end loop;
-- Finalization to compute the hash value.
SipHash48.Finalize(Hash, Output);

Compilation

In debug mode:

$ make

In release mode:

$ make BUILD_MODE=release

Testing

To run the tests:

$ make run_tests

Reference

J.-P. Aumasson and D. J. Bernstein, “SipHash: a fast short-input PRF.” 18-Sep-2012.

J.-P. Aumasson and D. J. Bernstein, "Reference C implementation"

License

This software is licensed under the BSD3 license.