Hawkynt

MWC256 (Multiply-with-Carry 256)

MWC256 is a multiply-with-carry generator with 256 32-bit elements invented by George Marsaglia. It achieves an extraordinary period of approximately 2^8222 through an array-based MWC approach. Known for excellent statistical properties and efficiency in embedded systems.

Properties

Property	Value
Category	Random Number Generators
Sub-category	Multiply-With-Carry
Security status	🎓 Educational Only
Complexity	Advanced
Inventor	George Marsaglia
Year	2003
Origin	🇺🇸 United States
Source	algorithms/random/mwc256.js

Parameters

Parameter	Supported values
Seed sizes	1 byte (8 bits) to 8 bytes (64 bits)

Capabilities

Flag	Value
IsDeterministic	Yes
IsCryptographicallySecure	No

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Documentation

• Marsaglia’s comp.lang.c Post (May 13, 2003) - MWC256 Reference Implementation
• Wikipedia: Multiply-with-carry pseudorandom number generator
• Marsaglia’s sci.math Post (Feb 25, 2003) - MWC256 Original Announcement
• Modern C Implementation of MWC256 (GitHub)

References

• Distribution Properties of MWC Generators
• Haskell mwc-random Package (MWC256 implementation)
• TestU01 Statistical Testing Suite

Test vectors

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

Vector 1 — Seed 0: First 5 outputs (20 bytes) - verified against C reference

Source: X:\Coding\Working Copies\Hawkynt.git\Hawkynt.github.io\Cipher\generate_mwc256_vectors.c

Field	Value
seed	0000000000000000
outputSize	20
input	null
expected	853985dd4d44ad486eb3d35a389c85df4dab581a

Vector 2 — Seed 1: First 5 outputs (20 bytes)

Source: X:\Coding\Working Copies\Hawkynt.git\Hawkynt.github.io\Cipher\verify_mwc256.c

Field	Value
seed	0000000000000001
outputSize	20
input	null
expected	abbf7382b9c63de8072c39b1e81359e13fc9883b

Vector 3 — Seed 42: First 5 outputs (20 bytes)

Source: X:\Coding\Working Copies\Hawkynt.git\Hawkynt.github.io\Cipher\verify_mwc256.c

Field	Value
seed	000000000000002a
outputSize	20
input	null
expected	03595d70f2fbe6a89e8aa771ba8da0dfe712ebdd

Vector 4 — Seed 1234567: First 8 outputs (32 bytes)

Source: X:\Coding\Working Copies\Hawkynt.git\Hawkynt.github.io\Cipher\verify_mwc256.c

Field	Value
seed	000000000012d687
outputSize	32
input	null
expected	63b2d6ee7ddc289bf248367e4ce3d7ccab2b932c118e6002cea2fcaaea750b8b

Vector 5 — Seed 987654321: First 8 outputs (32 bytes)

Source: X:\Coding\Working Copies\Hawkynt.git\Hawkynt.github.io\Cipher\verify_mwc256.c

Field	Value
seed	000000003ade68b1
outputSize	32
input	null
expected	996730de7c9749be79d140f50648de5cd4a6c28bf4bff9ba2884ec73ba3f879d

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