Hawkynt

ZK-Crypt v3 (DarkCrypt)

eSTREAM Profile II (hardware) ‘Variable Clocking Mechanism’ stream cipher: three irregularly-clocked nLFSR data banks with independent small nLFSR clock generators, a pseudo-random long/short clock, dual substitution hash matrices and a cipher/MAC feedback network, as implemented in the DarkCrypt Total Commander plugin.

Properties

Property	Value
Category	Stream Ciphers
Sub-category	Stream Cipher
Security status	🎓 Educational Only
Complexity	Expert
Inventor	Carmi Gressel, Orr Dunkelman, Gabi Vago, Ran Granot, Aviad Kipnis, Michael Rimon, Yaakov Belenky (FortressGB); DarkCrypt port by Alexander Myasnikov
Year	2006
Origin	🇮🇱 Israel
Source	algorithms/stream/darkcrypt-zkcrypt3.js

Parameters

Parameter	Supported values
Key sizes	20 bytes (160 bits)
Block sizes	1 byte (8 bits) to 65536 bytes (524288 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Reduced configuration	This build of the engine has the reference algorithm’s optional ‘Super tier’ nLFSR bank compiled out, and several literal C expressions in the reference source evaluate to a constant rather than their apparent intent. The resulting keystream is bit-exact to the DarkCrypt implementation but is a specific, non-configurable instance of the general ZK-Crypt v3 design.	Use a vetted, actively analyzed stream cipher.

Documentation

• DarkCrypt plugin (Total Commander PlugRing)
• eSTREAM: ZK-Crypt (base algorithm)

Test vectors

1 vector ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — DarkCrypt ZK-Crypt v3 — keystream from incrementing key, zero IV, zero input

Field	Value
key	000102030405060708090a0b0c0d0e0f10111213
iv	00000000000000000000000000000000
input	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
expected	bb3a598264069344c7a3d1c0d6b6eb4f 7eb4098e7fb2135053c9edde467f33c5 cd2d8364a1f38307ade7a8a365b589fe e90c2d0ee81e790d06875b6c7d6d867a ccaea351d4819026740ebe2e4cd31837 458b48d77fa991823defb988a7602e2b e25815cded92720379bfa7709f80926f f5153a5f8b2c6c05f95c4d1e07fb8ed2

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