New PRNG: w1rand that passed BigCrush and PractRand(512GB)

static inline uint64_t w1rand(uint64_t *s) {
  const uint64_t c = 0xd07ebc63274654c7ull;
  *s += c;
  __uint128_t t = (__uint128_t)*s * (*s ^ c);
  return (t >> 64) ^ t;
}

wyhash has evolved into rapidhash !
With improved speed, quality and compatibility.

No hash function is perfect, but some are useful.

wyhash and wyrand are the ideal 64-bit hash function and PRNG respectively:

solid: wyhash passed SMHasher, wyrand passed BigCrush, practrand.

portable: 64-bit/32-bit system, big/little endian.

fastest: Efficient on 64-bit machines, especially for short keys.

simplest: In the sense of code size.

salted: We use dynamic secret to avoid intended attack.

wyhash is the default hashing algorithm of the great Zig, V, Nim and Go (since 1.17) language. One milestone is that wyhash has deployed by Microsoft on [Windows Terminal] (https://github.com/microsoft/terminal/pull/13686).

Simple Example:

#include  "wyhash.h"
uint64_t _wyp[4];
make_secret(time(NULL),_wyp);
string  s="fcdskhfjs";
uint64_t h=wyhash(s.c_str(),s.size(),0,_wyp);

Limitations:

It is known now that wyhash/wyrand have their limitations:

Both of them are not 64 bit collision resistant, but is about 62 bits (flyingmutant/Cyan4973/vigna)

When test on longer dataset (32TB, 23 days), wyrand will fail practrand (vigna)

And there may be more flaws detected in the future.

User should make their own decision based the advantage and the flaws of wyhash/wyrand as no one is perfect.

---

C# https://github.com/cocowalla/wyhash-dotnet

C++ https://github.com/tommyettinger/waterhash

C++ https://github.com/alainesp/wy

GO https://github.com/dgryski/go-wyhash

GO https://github.com/orisano/wyhash

GO https://github.com/littleli/go-wyhash16

GO https://github.com/zeebo/wyhash

GO https://github.com/lonewolf3739/wyhash-go

GO https://github.com/zhangyunhao116/wyhash (final version 1 && 3)

Java https://github.com/OpenHFT/Zero-Allocation-Hashing

Java https://github.com/dynatrace-oss/hash4j (final version 3 and 4)

Kotlin Multiplatform https://github.com/appmattus/crypto/tree/main/cryptohash

Nim https://github.com/nim-lang/Nim/blob/devel/lib/pure/hashes.nim

Nim https://github.com/jackhftang/wyhash.nim

Nim https://github.com/littleli/nim-wyhash16

Rust https://github.com/eldruin/wyhash-rs

Swift https://github.com/lemire/SwiftWyhash

Swift https://github.com/lemire/SwiftWyhashBenchmark

Swift https://github.com/jeudesprits/PSWyhash

V https://github.com/vlang/v/tree/master/vlib/hash/wyhash (v4)

Zig https://github.com/ManDeJan/zig-wyhash

absl hashmap https://github.com/abseil/abseil-cpp/blob/master/absl/hash/internal/low_level_hash.h

---

I thank these names:

Reini Urban

Dietrich Epp

Joshua Haberman

Tommy Ettinger

Daniel Lemire

Otmar Ertl

cocowalla

leo-yuriev

Diego Barrios Romero

paulie-g

dumblob

Yann Collet

ivte-ms

hyb

James Z.M. Gao

easyaspi314 (Devin)

TheOneric

flyingmutant

vigna

tansy