Hawkynt

Xoshiro256**

Xoshiro256** is an all-purpose, rock-solid, small-state pseudo-random number generator with excellent speed and statistical properties. It features a 256-bit state, passes all statistical tests, and uses multiplication-based scrambler (star-star) for output function.

Properties

Property	Value
Category	Random Number Generators
Sub-category	Non-Cryptographic PRNG
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	David Blackman, Sebastiano Vigna
Year	2018
Origin	🇮🇹 Italy
Source	algorithms/random/xoshiro256starstar.js

Parameters

Parameter	Supported values
Seed sizes	8 bytes (64 bits)

Capabilities

Flag	Value
IsDeterministic	Yes
IsCryptographicallySecure	No

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Documentation

• Official Reference Implementation
• xoshiro / xoroshiro generators and the PRNG shootout
• Original Paper: Scrambled Linear Pseudorandom Number Generators (2018)

References

• Wikipedia: Xoroshiro128+
• PCG: A Quick Look at Xoshiro256**

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — Seed=0: First four 64-bit outputs from xoshiro256**

Field	Value
seed	0000000000000000
outputSize	32
input	null
expected	b4f275cb365fec992a455649781f6ebfe0e633499d845f1a2c2d2d26f194a56a

Vector 2 — Seed=1: First four 64-bit outputs from xoshiro256**

Field	Value
seed	0100000000000000
outputSize	32
input	null
expected	c510c70f6daff2b3ea4c364796553b8514452a085697f892a7a366c27b1c2e64

Vector 3 — Seed=12345: First four 64-bit outputs

Field	Value
seed	3930000000000000
outputSize	32
input	null
expected	9bd4604137366abec688a63706aa4a2188d35499de169df633e0964e8c04600c

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