CRC32
The checksum that catches cable noise.
Where it came from
CRC (Cyclic Redundancy Check) was formalized by W. Wesley Peterson in 1961 for reliable data transmission. CRC32 — a 32-bit variant — became ubiquitous in networking and storage: Ethernet frames, ZIP, PNG, and gzip all embed one.
It was never meant to stop attackers, only to catch accidental corruption: a flipped bit on a cable, a bad sector on disk.
How it works
CRC treats the message as a polynomial and divides it by a fixed generator, keeping the remainder as the checksum. A tiny change in input flips many bits of the CRC — great at spotting errors.
Crucially, CRC is not cryptographic: it is trivial to craft a collision. UWC computes CRC32 in your browser for integrity checks, never for security.