Strengthened variant of Py by Biham and Seberry: same rolling-array key/IV setup as Py, but the round output stage is simplified to a single fixed rotation (18) producing one 32-bit word per round instead of two. Ported from the DarkCrypt Total Commander plugin, which hardcodes a 512-bit key and 512-bit IV.
| Property | Value |
|---|---|
| Category | Stream Ciphers |
| Sub-category | Rolling-Array Stream Cipher |
| Security status | Not classified |
| Complexity | Advanced |
| Inventor | Eli Biham, Jennifer Seberry |
| Year | 2006 |
| Origin | 🇮🇱 Israel |
| Source | algorithms/stream/darkcrypt-pypy.js |
| Parameter | Supported values |
|---|---|
| Key sizes | 64 bytes (512 bits) |
| Nonce sizes | 64 bytes (512 bits) |
Status: not classified — treat as unverified.
| Issue | Description | Mitigation |
|---|---|---|
| Chosen-IV / distinguishing attacks | Pypy inherits Py’s flawed IV setup; broken by chosen-IV attacks and superseded by the tweaked TPypy. | Use TPypy or a vetted modern cipher. |
1 vector ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — DarkCrypt Pypy keystream
| Field | Value |
|---|---|
iv |
00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 |
key |
000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f |
input |
00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 |
expected |
108a776da56fee73215a9dc9742a6cd0 dfa653ac9c1c238d8912b0a989a7127a 94e25c603d91f10686270d71df2c2a58 8e316124462976c8badb9ed7c1db62b4 59749cecc8a443d61babf2db406e6708 6a0a46342359acca24cea2f9211267a6 9908ffa64ecb791a43393dc42d650491 51a9e03909829c1125558ea68d7c3f9f |