TLS (Transport Layer Security) uses a HYBRID encryption scheme. Why?

Question

Accepted Answer

D. asymmetric for key, symmetric for bulk

1. ASYMMETRIC encryption is too SLOW for bulk data. SYMMETRIC encryption is fast but has the KEY DISTRIBUTION problem.
2. HYBRID approach (used by TLS, S/MIME, PGP, etc.):
   • Use asymmetric crypto (RSA, ECDHE) to securely AGREE on a fresh session key during the handshake.
   • Use a fast symmetric cipher (AES-GCM, ChaCha20-Poly1305) to encrypt the actual data with that session key.
3. TLS 1.3 specifically uses Diffie-Hellman ephemeral key exchange (ECDHE) — providing FORWARD SECRECY.
4. Best of both worlds: the security of asymmetric for key agreement, the speed of symmetric for data.
5. Other options describe wrong setups or anti-patterns.
_Source: Boneh & Shoup, §21 (TLS architecture) + RFC 8446 (TLS 1.3)._

Answer

to make TLS slower

Answer

to use only RSA throughout the session

Answer

to avoid using any encryption