JA3

RU: JA3

A TLS client fingerprinting method created at Salesforce in 2017 that extracts selected numeric fields from the TLS ClientHello (protocol version, cipher suites, extensions, elliptic curves, and curve formats), concatenates them, and produces an MD5 hash. The resulting 32-character string identifies client libraries and can detect known-malicious clients, though modern browsers that randomize extension order reduce its reliability.