Hawkynt

Curupira-2 (DarkCrypt)

Curupira-2 block cipher (Simplicio, Barreto, Carvalho, Margi, Naslund, 2007) as implemented in the DarkCrypt Total Commander plugin: shares Curupira-1’s involutional round function (S-box, row permutation, GF(2^8) MDS diffusion, key XOR) over a 3x4 byte state, but replaces the key schedule with a GF(2^(48t)) Galois-LFSR-style evolution. 96-bit block, 96/144/192-bit key. Only the 192-bit key path was vector-validated against the DarkCrypt implementation.

Properties

Property Value
Category Block Ciphers
Sub-category Block Cipher
Security status 🎓 Educational Only
Complexity Advanced
Inventor Marcos A. Simplicio Jr., Paulo S. L. M. Barreto, Tereza C. M. B. Carvalho, Cintia B. Margi, Mats Naslund (base cipher); DarkCrypt port by Alexander Myasnikov
Year 2007
Origin 🇧🇷 Brazil
Source algorithms/block/darkcrypt-curupira2.js

Parameters

Parameter Supported values
Key sizes 12 bytes (96 bits) to 24 bytes (192 bits) in steps of 6 bytes
Block sizes 12 bytes (96 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue Description Mitigation
Unanalyzed variant Round count and key-schedule details calibrated against a single DarkCrypt build rather than the original academic specification; not recommended for real use. 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 Curupira2 — zero key/plaintext (192-bit key)

Field Value
key 000000000000000000000000000000000000000000000000
input 000000000000000000000000
expected d97d2c29506cb633b5aa2a43

Vector 2 — DarkCrypt Curupira2 — incrementing key/plaintext (192-bit key)

Field Value
key 000102030405060708090a0b0c0d0e0f1011121314151617
input 000102030405060708090a0b
expected 77ba02249f52ad21bed4794f

Vector 3 — DarkCrypt Curupira2 — shifted incrementing key/plaintext (192-bit key)

Field Value
key 0102030405060708090a0b0c0d0e0f101112131415161718
input 101112131415161718191a1b
expected dcc0d63e13095c6187a165e3

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