BBC (DarkCrypt)
BBC keystream/permutation cipher from the DarkCrypt Total Commander plugin. Exposed through the block interface with a 256 KiB block, but internally three additive lagged-Fibonacci generators (seeded from 3 key bytes) build sixteen key-dependent S-boxes for two chained substitution passes plus a full-block involution shuffle.
Properties
| Property |
Value |
| Category |
Block Ciphers |
| Sub-category |
Block Cipher |
| Security status |
🎓 Educational Only |
| Complexity |
Intermediate |
| Inventor |
Alexander Myasnikov (DarkCrypt plugin) |
| Year |
2013 |
| Origin |
🇷🇺 Russia |
| Source |
algorithms/block/darkcrypt-bbc.js |
Parameters
| Parameter |
Supported values |
| Key sizes |
12 bytes (96 bits) |
| Block sizes |
262144 bytes (2097152 bits) |
Security
Status: 🎓 Educational Only
Known vulnerabilities
| Issue |
Description |
Mitigation |
| Tiny effective key |
Only the first 3 of the 12 key bytes influence the output, giving at most a 24-bit effective key space that is trivially brute-forced. |
Do not use for confidentiality; use AES or another vetted cipher. |
| Non-standard construction |
Ad-hoc lagged-Fibonacci keystream with key-derived S-boxes; unanalyzed and not recommended for real use. |
Use a vetted cipher. |
Documentation
Test vectors
2 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — DarkCrypt Bbc — zero key, all-zero 256 KiB plaintext
| Field |
Value |
key |
000000000000000000000000 |
input |
00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 … (262144 bytes; the full value is in the source) |
expected |
0dc1a6bce4a38eb7f824a3af534d5916 5fce0f92df67ac6ebfff147190ef38d1 40e9906aedc24aaa2fbdeb06dc040bf1 35d8dc38ba4772c512ed60780fddfb53 … (262144 bytes; the full value is in the source) |
Vector 2 — DarkCrypt Bbc — incrementing key, counting-pattern 256 KiB plaintext (verified against the DarkCrypt implementation)
| Field |
Value |
key |
0102030405060708090a0b0c |
input |
000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f … (262144 bytes; the full value is in the source) |
expected |
5f83b36e1d7565b7a552c55d715a6aec 4089908fa2bf9ff541ec3cefad664935 b63e9764776107d5a703df117bd078fe 241df11854881c85885a877ab5910347 … (262144 bytes; the full value is in the source) |
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