Stac Lempel-Ziv-Stac compression as specified for PPP by RFC 1974. A continuous MSB-first bit stream mixes 8-bit literals with back-references whose offset is coded as either 7 or 11 bits and whose length uses a nested nibble/escape code, terminated by a fixed 9-bit end marker.
| Property | Value |
|---|---|
| Category | Compression Algorithms |
| Sub-category | Dictionary-based |
| Security status | Not classified |
| Complexity | Intermediate |
| Inventor | Stac Electronics |
| Year | 1996 |
| Origin | 🇺🇸 United States |
| Source | algorithms/compression/lzs.js |
Status: not classified — treat as unverified.
No vulnerabilities are recorded for this implementation.
3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — Empty input
| Field | Value |
|---|---|
input |
(empty) |
expected |
00000000 |
Vector 2 — Highly repetitive input (40 ‘A’ bytes)
| Field | Value |
|---|---|
input |
41414141414141414141414141414141 41414141414141414141414141414141 4141414141414141 |
expected |
280000002090703ff9e000 |
Vector 3 — Text sample
| Field | Value |
|---|---|
input |
74686520717569636b2062726f776e20 666f78206a756d7073206f7665722074 6865206c617a7920646f672e20746865 20717569636b2062726f776e20666f78 2e |
expected |
410000003a1a0ca20389d4d26335880c 472379dcdc20331bcf020351d4da7039 880de76329c8419f8d8613d1e4406437 99c5d8ec35bd0bb000 |