8-bit two’s complement checksum. Sums all bytes modulo 256, then returns two’s complement (negate). Verification: sum of all data bytes plus checksum equals zero (mod 256).
| Property | Value |
|---|---|
| Category | Checksums |
| Sub-category | Twos Complement |
| Security status | 🎓 Educational Only |
| Complexity | Beginner |
| Inventor | Unknown (fundamental technique) |
| Year | 1960 |
| Origin | Not specified |
| Source | algorithms/checksum/complement.js |
Status: 🎓 Educational Only
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 — Byte sum 0x06, 8-bit complement 0xFA
| Field | Value |
|---|---|
input |
010203 |
expected |
fa |
Vector 2 — Serial protocol example
| Field | Value |
|---|---|
input |
25623f52 |
expected |
e8 |
Vector 3 — Byte sum 0xFF, 8-bit complement 0x01
| Field | Value |
|---|---|
input |
ff |
expected |
01 |