PES (Proposed Encryption Standard, Lai/Massey 1990), the direct historical predecessor of IDEA, as implemented in the DarkCrypt Total Commander plugin. Same Lai-Massey structure and multiplication-mod-65537 arithmetic as IDEA over four 16-bit sub-blocks, but with a simpler bit-rotating round-key derivation lacking IDEA’s stronger key mixing. 8 full rounds plus a final half-round.
| Property | Value |
|---|---|
| Category | Block Ciphers |
| Sub-category | Block Cipher |
| Security status | 🎓 Educational Only |
| Complexity | Intermediate |
| Inventor | Xuejia Lai, James L. Massey |
| Year | 1990 |
| Origin | 🇨🇭 Switzerland |
| Source | algorithms/block/darkcrypt-pes.js |
| Parameter | Supported values |
|---|---|
| Key sizes | 16 bytes (128 bits) |
| Block sizes | 8 bytes (64 bits) |
Status: 🎓 Educational Only
| Issue | Description | Mitigation |
|---|---|---|
| Weak key schedule | PES’s simpler round-key derivation (relative to its IDEA successor) was shown to be cryptanalytically weak, which is precisely why IDEA replaced it. | Use IDEA, AES, or another vetted cipher. |
3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — DarkCrypt Pes — incrementing key, zero plaintext
| Field | Value |
|---|---|
key |
000102030405060708090a0b0c0d0e0f |
input |
0000000000000000 |
expected |
e8f608b37a36627a |
Vector 2 — DarkCrypt Pes — incrementing key, incrementing plaintext
| Field | Value |
|---|---|
key |
000102030405060708090a0b0c0d0e0f |
input |
0001020304050607 |
expected |
722ddbe59d2ad932 |
Vector 3 — DarkCrypt Pes — random key/plaintext (verified against the DarkCrypt implementation)
| Field | Value |
|---|---|
key |
9171a8c51545e90a32f8680f716e4cc7 |
input |
fc0d3cc6a6b8e6aa |
expected |
5d8831507b5ba3b7 |