Portable
No platform-specific path
No SIMD, 128-bit multiply, hardware-specific instructions, or undefined behavior. Output is independent of host endianness.
Experimental · non-cryptographic
hayahash64
A small, fast, portable 64-bit hash function. It is a successor experiment to ChibiHash v1 and v2, with higher measured speed and the same strict portability rules.
- Output
- 64-bit
- API
hayahash64(key, len, seed)- Targets
- C99 and
no_stdRust - Quality
- 188/188 SMHasher3 tests
- Verify
0x6B558D9D- License
- Public domain / Unlicense
188/188
SMHasher3 tests passed
26.8 GB/s
1 MiB input, Apple M1
9.64 B/cy
SMHasher3 bulk test
31.4 cy
Average, 1–31 byte keys
Use
The reference implementation is one C header. The Rust port is bit-exact against it.
#include "hayahash.h"
uint64_t h = hayahash64(buf, len, seed);Rust
View portlet h = hayahash::hayahash64(buf, seed);Properties
Fast
Short dependency chains
Eight independent lanes process 64-byte blocks. Tail reads overlap, so no byte-at-a-time tail loop is required.
Checked
Full current test suite
The C reference passes 188/188 SMHasher3 tests. The Rust port checks the verification value and shared known-answer vectors.
Design in four points
- Bulk path
-
Eight lanes keep the loop-carried path to an
add → multiplychain over 64-byte blocks. - Absorb
- Each lane absorbs the current stripe plus a rotated copy of the previous stripe, making the absorb sequence injective by first-difference induction.
- State
- Seed and input length are premixed. Lane constants are derived from that value and one multiplier constant.
- Short inputs
- Inputs up to 16 bytes use overlapping whole-word reads, independent bijective injections, two multiplies, and a strong finalizer.
Do not use for
Security boundaries
- Message authentication
- Password hashing
- Adversarial collision resistance
- Any cryptographic purpose
Stable persisted identifiers
This is an experimental prototype. Digest compatibility is not promised between revisions.