Hawkynt

DFC-128/256 (DarkCrypt)

Decorrelated Fast Cipher (DFCv1): 8-round Feistel network with a round function based on 64-bit modular multiply-add mod 2^64+13 followed by a table-based confusion permutation. 128-bit block, 256-bit key. As implemented in the DarkCrypt Total Commander plugin, matching the standard DFCv1 AES-submission construction exactly.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Block Cipher
Security status	🎓 Educational Only
Complexity	Advanced
Inventor	Serge Vaudenay, Loïc Granboulan, Fabrice Levy-dit-Vehel, Phong Nguyen, Thomas Pornin, Jacques Stern (ENS/CNRS/France Télécom); DarkCrypt packaging by Alexander Myasnikov
Year	1998
Origin	🇷🇺 Russia
Source	algorithms/block/darkcrypt-dfc.js

Parameters

Parameter	Supported values
Key sizes	32 bytes (256 bits)
Block sizes	16 bytes (128 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Weak keys / reduction concerns	Coppersmith identified weak-key issues in the original key schedule (addressed by the later DFCv2 revision); not selected as an AES finalist.	Use AES or another vetted cipher.

Documentation

• DarkCrypt plugin (Total Commander PlugRing)
• DFC (Decorrelated Fast Cipher) (Wikipedia)
• On the Decorrelated Fast Cipher (DFC) and Its Theory (Knudsen, Rijmen)

Test vectors

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

Vector 1 — NIST AES round-1 DFC KAT ecb_vk.txt, KEYSIZE=256, I=1

Field	Value
key	8000000000000000000000000000000000000000000000000000000000000000
input	00000000000000000000000000000000
expected	b098bb87597a3fb0dca816d24021e65e

Vector 2 — DarkCrypt Dfc — zero key/plaintext

Field	Value
key	0000000000000000000000000000000000000000000000000000000000000000
input	00000000000000000000000000000000
expected	0205d7133ed37cee091c36f24a74592a

Vector 3 — DarkCrypt Dfc — incrementing key/plaintext

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
input	000102030405060708090a0b0c0d0e0f
expected	e2dcada042d08fa0426707e23d34c08d

Vector 4 — DarkCrypt Dfc — shifted incrementing key/plaintext

Field	Value
key	0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20
input	101112131415161718191a1b1c1d1e1f
expected	8b3a1c45c001590bd00477f664e98c44

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