jm + siphash   4

google/highwayhash: Fast strong hash functions: SipHash/HighwayHash
HighwayHash: 'We have devised a new way of mixing inputs with AVX2 multiply and permute instructions. The multiplications are 32x32 -> 64 bits and therefore infeasible to reverse. Permuting equalizes the distribution of the resulting bytes. The internal state occupies four 256-bit AVX2 registers. Due to limitations of the instruction set, the registers are partitioned into two 512-bit halves that remain independent until the reduce phase. The algorithm outputs 64 bit digests or up to 256 bits at no extra cost. In addition to high throughput, the algorithm is designed for low finalization cost. The result is more than twice as fast as SipTreeHash.

We also provide an SSE4.1 version (80% as fast for large inputs and 95% as fast for short inputs), an implementation for VSX on POWER and a portable version (10% as fast). A third-party ARM implementation is referenced below.

Statistical analyses and preliminary cryptanalysis are given in https://arxiv.org/abs/1612.06257.'

(via Tony Finch)
siphash  highwayhash  via:fanf  hashing  hashes  algorithms  mac  google  hash 
6 weeks ago by jm
Accidentally Quadratic — Rust hash iteration+reinsertion
It was recently discovered that some surprising operations on Rust’s standard hash table types could go quadratic.


Quite a nice unexpected accidental detour into O(n^2)
big-o  hashing  robin-hood-hashing  siphash  algorithms  hashtables  rust 
november 2016 by jm
29c3 HashDOS presentation slides (PDF)
Summary: MurmurHash still vulnerable, likewise Cityhash and Python's hash -- use SipHash
via:fanf  cityhash  siphash  hash  dos  security  hashdos  murmurhash 
january 2013 by jm
SipHash: a fast short-input PRF
a family of pseudorandom functions optimized for short inputs. Target applications include network traffic authentication and hash-table lookups protected against hash-flooding denials-of-service attacks.

SipHash is simpler than MACs based on universal hashing, and faster on short inputs.

Compared to dedicated designs for hash-table lookup, SipHash has well-defined security goals and competitive performance. For example, SipHash processes a 16-byte input with a fresh key in 140 cycles on an AMD FX-8150 processor, which is much faster than state-of-the-art MACs.
hashing  siphash  djb  security  algorithms 
october 2012 by jm

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