AES-GCM is a NIST standardised authenticated encryption algorithm (FIPS 800-38D). Since its standardisation in 2008 its usage increased to a point where it is the prevalent encryption used with TLS. With 85% it is by far the most widely used cipher. Firefox 53 TLS cipher telemetry Unfortunately the AES-GCM implementation used in Firefox (provided by NSS) does not take advantage of full hardware acceleration; it uses a slower software-only implementation on Mac, Linux 32-bit, or any device that doesn’t have the AVX, PCLMUL, and AES-NI hardware instructions.