The SQX archiver’s LZH method: an LZ77 matcher over a 32 KiB dictionary feeding a 310-symbol main tree that folds literals, four repeated-distance slots, length-2 and length-3 matches with inline distances, and 25 length-4-or-more slots into one alphabet, alongside a 48-slot distance tree. Per-block code lengths travel through a 19-symbol pre-tree written as raw 4-bit fields, and all bit fields are most-significant-bit first.
| Property | Value |
|---|---|
| Category | Compression Algorithms |
| Sub-category | Dictionary |
| Security status | Not classified |
| Complexity | Advanced |
| Inventor | Rainer Nausedat |
| Year | 2004 |
| Origin | 🇩🇪 Germany |
| Source | algorithms/compression/sqx.js |
Status: not classified — treat as unverified.
No vulnerabilities are recorded for this implementation.
4 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — Empty input - length header only
| Field | Value |
|---|---|
input |
(empty) |
expected |
00000000 |
Vector 2 — Single byte ‘A’ - one literal
| Field | Value |
|---|---|
input |
41 |
expected |
0100000000010100000000000000001b67fefd280000 |
Vector 3 — Repeated byte run - one literal then a length-4-or-more match
| Field | Value |
|---|---|
input |
61616161616161616161616161616161 |
expected |
1000000000020100000000000000001d67fd721548c00000 |
Vector 4 — Periodic text - literals then a match carrying extra length bits
| Field | Value |
|---|---|
input |
6162636162636162636162636162636162636162 |
expected |
140000000004332000000000000000156a9fcb604db910da800000 |