Hawkynt

SNOW 2.0 (DarkCrypt)

Ekdahl and Johansson’s SNOW 2.0 stream cipher (16-word GF(2^32) LFSR + AES-S-box-based FSM), as implemented in the DarkCrypt Total Commander plugin’s 256-bit-key-only build. The algorithm core is bit-exact to the published SNOW 2.0 specification.

Properties

Property	Value
Category	Stream Ciphers
Sub-category	Stream Cipher
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	Patrik Ekdahl, Thomas Johansson (base design); DarkCrypt port by Alexander Myasnikov
Year	2002
Origin	🇸🇪 Sweden
Source	algorithms/stream/darkcrypt-snow2.js

Parameters

Parameter	Supported values
Key sizes	32 bytes (256 bits)
Block sizes	1 byte (8 bits) to 65536 bytes (524288 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Distinguishing attacks	SNOW 2.0 has known distinguishing attacks with complexity below exhaustive search in academic literature; superseded by SNOW 3G / SNOW-V for production use.	Use a vetted, currently-recommended stream cipher.

Documentation

• DarkCrypt plugin (Total Commander PlugRing)
• SNOW 2.0 specification (Ekdahl and Johansson)

Test vectors

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

Vector 1 — DarkCrypt Snow2 — keystream from incrementing key, zero IV, zero input

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
iv	00000000000000000000000000000000
input	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
expected	7aa40e9615aed53d3a69c1ddc2912a1a 86dafe5c0432ac08956837bd05ab2009 1989294a98d23cf63531e62ae1873175 524a2f14ce103ae166ab132c435767ef e875062bddf190d760d4c635ffaffd36 0f399c3c4f2df769d1590f74f034917a a0db223318e74778f9181a8e0c893c61 59191db89f5ffd40293fbc8cba6a39b1

Vector 2 — DarkCrypt Snow2 — incrementing key/plaintext, zero IV

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
iv	00000000000000000000000000000000
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	7aa50c9511abd33a3260cbd6ce9c2415 96cbec4f1027ba1f8d712da619b63e16 39a80b69bcf71ad11d18cc01cdaa1f5a 627b1d27fa250cd65e9229177f6a59d0

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