TLS_CHACHA20_POLY1305_SHA256
TLS_CHACHA20_POLY1305_SHA256
TLS_CHACHA20_POLY1305_SHA256 is a TLS 1.3 cipher suite using the ChaCha20-Poly1305 AEAD algorithm. ChaCha20 is a stream cipher designed to be fast on hardware without AES acceleration – making it the preferred choice for mobile devices and IoT. Google designed it specifically to outperform AES on ARM processors without AES-NI.
Key Exchange
ECDHE (built into TLS 1.3 handshake)
Authentication
Signature algorithm negotiated separately
Encryption
ChaCha20
MAC / Integrity
Poly1305 (AEAD – integrated)
Details
ChaCha20-Poly1305 was designed by Daniel J. Bernstein and adopted by Google for QUIC and Chrome. ChaCha20 (the stream cipher) and Poly1305 (the MAC) together form an AEAD construction. On devices without AES hardware acceleration, ChaCha20-Poly1305 is 3–4x faster than AES-GCM. TLS 1.3 includes it as a mandatory cipher suite alongside the AES variants. Cloudflare and Google prioritize ChaCha20-Poly1305 for mobile connections.