SipHash

SipHash is an Add-Rotate-Xor (ARX) based family of pseudorandom functions created by Jean-Philippe Aumasson and Daniel J. Bernstein in 2012.

Overview

SipHash computes 64-bit message authentication code from a variable-length message and 128-bit secret key. It was designed to be efficient even for short inputs, with performance comparable to non-cryptographic hash functions, such as CityHash, thus can be used in hash tables to prevent DoS collision attack (hash flooding) or to authenticate network packets.

Functions in SipHash family are specified as SipHash-c-d, where c is the number of rounds per message block and d is the number of finalization rounds. The recommended parameters are SipHash-2-4 for best performance, and SipHash-4-8 for conservative security.

The reference implementation was released as public domain software under the CC0.

Usage

SipHash is used in hash table implementations of various software:

• Perl (available as compile-time option)
• Python (starting in version 3.4)
• Ruby
• Rust
• systemd
• OpenDNS
• Haskell
• OpenBSD

Native Implementations

• Javascript
• Haskell
• VHDL
• C++

See also

• Cryptographic hash function
• Hash function
• List of hash functions