FOX128/256/32 (IDEA NXT-128 with a 256-bit key, 32 rounds): an Extended Lai-Massey block cipher by Junod and Vaudenay (EPFL), built from an f64 substitution-diffusion round function (sigma8 S-box layer plus an (8,8) MDS mu8 matrix over GF(2^8)) and orthomorphisms. 128-bit block, 256-bit key. As implemented by the DarkCrypt Total Commander plugin, which uses 32 rounds (vs. the generic FOX128/256 default of 16) and an all-zero key-schedule pad constant.
| Property | Value |
|---|---|
| Category | Block Ciphers |
| Sub-category | Block Cipher |
| Security status | 🎓 Educational Only |
| Complexity | Advanced |
| Inventor | Pascal Junod, Serge Vaudenay (EPFL); DarkCrypt port by Alexander Myasnikov |
| Year | 2004 |
| Origin | 🇨🇭 Switzerland |
| Source | algorithms/block/darkcrypt-ideanxt.js |
| Parameter | Supported values |
|---|---|
| Key sizes | 32 bytes (256 bits) |
| Block sizes | 16 bytes (128 bits) |
Status: 🎓 Educational Only
| Issue | Description | Mitigation |
|---|---|---|
| Patent-encumbered design | IDEA NXT/FOX was covered by software patents held by MediaCrypt AG; unrelated to any cryptographic weakness. | Use AES or another vetted, unencumbered cipher. |
3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — DarkCrypt Ideanxt — zero key/plaintext
| Field | Value |
|---|---|
key |
0000000000000000000000000000000000000000000000000000000000000000 |
input |
00000000000000000000000000000000 |
expected |
180880d3e4ea58fc61294492bcb46ae6 |
Vector 2 — DarkCrypt Ideanxt — incrementing key/plaintext
| Field | Value |
|---|---|
key |
000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f |
input |
000102030405060708090a0b0c0d0e0f |
expected |
7cfe4b5c127efe0676dc062e929b2846 |
Vector 3 — DarkCrypt Ideanxt — shifted incrementing key/plaintext
| Field | Value |
|---|---|
key |
0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20 |
input |
101112131415161718191a1b1c1d1e1f |
expected |
41d8033ba27c7f215294ca9b0cf25211 |