Tagged: ja4

JA4+ in depth: JA4, JA4S, JA4H, JA4L, JA4X and what each captures

A reference walk through the full JA4+ suite: how each of JA4, JA4S, JA4H, JA4L, JA4X, JA4T and JA4SSH is constructed, what it captures, and how the a_b_c format lets the parts compose.

tls fingerprinting ja4

Tue, March 10, 2026 · 22 min read

TLS extension ordering and the Chrome randomization that broke JA3

How the order of TLS extensions became a fingerprint, why Chrome started shuffling that order in early 2023 with a Fisher-Yates permutation in BoringSSL, and how JA4 answered by sorting the list.

tls fingerprinting ja4

Fri, March 6, 2026 · 20 min read