Welch-Gong (WG) transformation stream cipher: an 11-stage LFSR over GF(2^29) filtered by a degree-11 normal-basis nonlinear transformation. DarkCrypt’s variant uses a compact byte-interleaved key/IV load, always a 128-bit key and 128-bit IV, and 44 nonlinear-feedback initialization clocks with a tap-11-inclusive key-init vector.
| Property | Value |
|---|---|
| Category | Stream Ciphers |
| Sub-category | Stream Cipher |
| Security status | 🎓 Educational Only |
| Complexity | Advanced |
| Inventor | Yassir Nawaz, Guang Gong (base WG design); DarkCrypt variant |
| Year | 2005 |
| Origin | 🇨🇦 Canada |
| Source | algorithms/stream/darkcrypt-wg.js |
| Parameter | Supported values |
|---|---|
| Key sizes | 16 bytes (128 bits) |
| Block sizes | 1 byte (8 bits) to 65536 bytes (524288 bits) |
Status: 🎓 Educational Only
| Issue | Description | Mitigation |
|---|---|---|
| Non-standard variant | Modified WG cipher with a DarkCrypt-specific key/IV load and initialization schedule; not equivalent to the reviewed eSTREAM submission and not recommended for real use. | Use a vetted stream cipher. |
2 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — DarkCrypt Wg — keystream from incrementing key, zero IV, zero input
| Field | Value |
|---|---|
key |
000102030405060708090a0b0c0d0e0f |
iv |
00000000000000000000000000000000 |
input |
00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 |
expected |
ae0921b826d05f4df117e08fc6609be4 42e73d8683f6bb5d3064cfe387b40a40 2c54f4772c3af5503b5b7fa041c8a35c c5b90e57bc31eaa63321760a632b0fbd 5920703d4cb40fd2222bdbc5bc3afeb9 cd11554f199bddb7cb510acd97be0af8 90a58a5810afde38e6eda91632e166b5 ed710656e6f9604f6466dc2a3b2a62f1 |
Vector 2 — DarkCrypt Wg — incrementing key, zero IV, incrementing plaintext
| Field | Value |
|---|---|
key |
000102030405060708090a0b0c0d0e0f |
iv |
00000000000000000000000000000000 |
input |
000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f |
expected |
ae0823bb22d5594af91eea84ca6d95eb 52f62f9597e3ad4a287dd5f89ba9145f 0c75d654081fd3771372558b6de58d73 f5883c648804dc910b184c315f163182 |