Encryption at Rest vs Encryption in Transit

Encryption in transit protects network packets moving between clients and load balancers, or between internal microservices, preventing eavesdropping, man-in-the-middle (MITM) tampering, and session hijacking.

TLS 1.3 vs Legacy TLS 1.2:

• 1-RTT Handshake (and 0-RTT Resumption): TLS 1.3 reduces connection establishment latency from 2 round trips (2-RTT) to a single round trip (1-RTT), saving 50-100ms on mobile connections.
• Removed Insecure Cryptographic Primitives: Completely eliminates vulnerable legacy ciphers (CBC-mode ciphers, RC4, 3DES, MD5, SHA-1) and static RSA key exchange.
• Modern Authenticated Ciphers: Strictly supports Authenticated Encryption with Associated Data (AEAD) ciphers:
  • TLS_AES_256_GCM_SHA384 (Hardware-accelerated AES-NI on Intel/AMD CPUs)
  • TLS_CHACHA20_POLY1305_SHA256 (High-performance on mobile/ARM chips without dedicated AES silicon)

Perfect Forward Secrecy (PFS):

TLS 1.3 mandates Ephemeral Diffie-Hellman (ECDHE: X25519) key exchange. For every single session, a unique ephemeral session key is derived.

• The Security Guarantee: Even if an attacker records encrypted network traffic for 10 years and later steals the server's long-term private TLS certificate, they cannot decrypt past recorded sessions.