Hawkynt

CryptMT3 (DarkCrypt)

CryptMT version 3: an F2-linear (SFMT-family) generator combined with a nonlinear multiplicative filter with memory (Matsumoto, Saito, Nishimura, Hagita). Key and IV are packed into 128-bit blocks, concatenated, duplicated, and whitened with the digits of pi before a multiplicative ‘booter’ seeds the output filter. The DarkCrypt Total Commander plugin implements the published reference algorithm essentially verbatim for a 512-bit key and 512-bit IV.

Properties

Property	Value
Category	Stream Ciphers
Sub-category	Stream Cipher
Security status	🎓 Educational Only
Complexity	Advanced
Inventor	Makoto Matsumoto, Mutsuo Saito, Takuji Nishimura, Mariko Hagita
Year	2007
Origin	🇯🇵 Japan
Source	algorithms/stream/darkcrypt-cryptmt3.js

Parameters

Parameter	Supported values
Key sizes	64 bytes (512 bits)
Block sizes	1 byte (8 bits) to 1248 bytes (9984 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Unproven multiplicative filter	CryptMT’s security relies on an integer-multiplication-based nonlinear filter whose resistance to algebraic/statistical attack is less well understood than LFSR-only designs; it was not selected for the eSTREAM portfolio.	Use a vetted, portfolio-selected stream cipher.

Documentation

• DarkCrypt plugin (Total Commander PlugRing)
• CryptMT Stream Cipher Version 3 (Hiroshima University)
• Reference implementation (magurosan/CryptMT)

Test vectors

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

Vector 1 — DarkCrypt Mt3 — keystream from incrementing key, zero IV, zero input

Field	Value
key	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
iv	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
input	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
expected	16c2831f942a0205bb448977fb9d5ecf 5e94e40a3b4e4bd193c26baafbce05db 6dd9b17d11ecc2ef2e49b6c136638576 7def6b6c2e81cd5f1a4220b61f04d008 919fcfe754964b8da34c45ef41478985 65b1d2906d26c4bda7e3c753478bbc6a 89cb9c30b6b1cd076d69bf1ca45c8343 e8d4aad3fc339c7c7634ff34a9aa6363

Vector 2 — DarkCrypt Mt3 — incrementing key, zero IV, incrementing plaintext

Field	Value
key	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
iv	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	16c3811c902f0402b34d837cf79050c0 4e85f6192f5b5dc68bdb71b1e7d31bc4 4df8935e35c9e4c806609cea1a4eab59 4dde595f1ab4fb68227b1a8d2339ee37

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