Hawkynt

XOR-8

Simple XOR-based checksum used in NMEA GPS sentences and serial communication protocols. XORs all input bytes to produce a single-byte error detection value.

Properties

Property	Value
Category	Checksums
Sub-category	XOR-based
Security status	🎓 Educational Only
Complexity	Beginner
Inventor	Unknown (ancient technique)
Year	1960
Origin	Not specified
Source	`algorithms/checksum/xor-checksum.js`

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Notes

Very simple: XOR all bytes together
Used in NMEA GPS sentences (between $ and *)
Can detect odd number of bit errors
Cannot detect even number of identical bit errors
Fast and lightweight for embedded systems
Often displayed as 2-digit hexadecimal

Documentation

References

pynmea2 XOR checksum implementation

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — NMEA sentence type

Field	Value
`input`	`4750524d43`
`expected`	`4b`

Vector 2 — Simple sequence

Source: XOR checksum calculation

Field	Value
`input`	`01020304`
`expected`	`04`

Vector 3 — ASCII test

Source: XOR checksum test

Field	Value
`input`	`414243`
`expected`	`40`

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