Pypy (DarkCrypt)
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.
Properties
| Property |
Value |
| Category |
Stream Ciphers |
| Sub-category |
Rolling-Array Stream Cipher |
| Security status |
❌ Broken |
| Complexity |
Advanced |
| Inventor |
Eli Biham, Jennifer Seberry |
| Year |
2006 |
| Origin |
🇮🇱 Israel |
| Source |
algorithms/stream/darkcrypt-pypy.js |
Parameters
| Parameter |
Supported values |
| Key sizes |
64 bytes (512 bits) |
| Nonce sizes |
64 bytes (512 bits) |
Security
Status: ❌ Broken
Known vulnerabilities
| 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Pypy inherits Py’s flawed IV setup; broken by chosen-IV attacks and superseded by the tweaked TPypy.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. |
Documentation
References
Test vectors
2 vectors 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 |
Vector 2 — DarkCrypt Pypy — non-zero key and IV, 48-byte message (verified against the DarkCrypt implementation)
| Field |
Value |
key |
0b30557a9fc4e90e33587da2c7ec1136 5b80a5caef14395e83a8cdf2173c6186 abd0f51a3f6489aed3f81d42678cb1d6 fb20456a8fb4d9fe23486d92b7dc0126 |
iv |
073c71a6db10457aafe4194e83b8ed22 578cc1f62b6095caff34699ed3083d72 a7dc11467bb0e51a4f84b9ee23588dc2 f72c6196cb00356a9fd4093e73a8dd12 |
input |
03203d5a7794b1ceeb0825425f7c99b6 d3f00d2a4764819ebbd8f5122f4c6986 a3c0ddfa1734516e8ba8c5e2ff1c3956 |
expected |
73377697e55a2666d2af7a41dbd8c31e f749f682826de5ca75e5e59641c426a1 09fb41152626e020f6019375395845a8 |
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