TLS_AES_128_GCM_SHA256
TLS_AES_128_GCM_SHA256
TLS_AES_128_GCM_SHA256 is one of the five mandatory TLS 1.3 cipher suites. It uses AES-128 in GCM mode for authenticated encryption. In TLS 1.3, all cipher suites use ECDHE for key exchange implicitly – it is not part of the cipher suite name. This is the most widely used TLS 1.3 cipher suite.
Key Exchange
ECDHE (built into TLS 1.3 handshake)
Authentication
Signature algorithm negotiated separately
Encryption
AES-128-GCM
MAC / Integrity
SHA-256 (AEAD – integrated)
Details
TLS 1.3 redesigned cipher suites to include only the symmetric encryption algorithm and MAC. Key exchange and authentication are handled by the handshake separately. AES-128-GCM provides authenticated encryption (AEAD) – it simultaneously encrypts and verifies integrity without a separate HMAC step. 128-bit AES is considered secure for all practical purposes and is faster than 256-bit on hardware without AES-NI acceleration.