Hawkynt

Umchak (DarkCrypt)

TEA-family block cipher from the DarkCrypt Total Commander plugin: 64-bit block, 512-bit key, 64-word round-key schedule built by an RC5-constant-driven S-box mixing pass followed by a modified RC4-style permutation.

Properties

Property Value
Category Block Ciphers
Sub-category Block Cipher
Security status 🎓 Educational Only
Complexity Advanced
Inventor DarkCrypt variant by Alexander Myasnikov
Year 2013
Origin 🇷🇺 Russia
Source algorithms/block/darkcrypt-umchak.js

Parameters

Parameter Supported values
Key sizes 64 bytes (512 bits)
Block sizes 8 bytes (64 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue Description Mitigation
Unanalyzed non-standard cipher Undocumented DarkCrypt-specific design with no public cryptanalysis. Use AES or another vetted cipher.

Documentation

Test vectors

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

Vector 1 — DarkCrypt Umchak — zero key/plaintext

Field Value
key 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
input 0000000000000000
expected f6d28498b21e3b96

Vector 2 — DarkCrypt Umchak — incrementing key/plaintext

Field Value
key 000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
input 0001020304050607
expected a9c7de5d888323cb

Vector 3 — DarkCrypt Umchak — shifted incrementing key/plaintext

Field Value
key 0102030405060708090a0b0c0d0e0f10 1112131415161718191a1b1c1d1e1f20 2122232425262728292a2b2c2d2e2f30 3132333435363738393a3b3c3d3e3f40
input 1011121314151617
expected 567f7aa3640a8177

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