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- 2071 Shrawan · 4 marks
- 2071 Chaitra · 4 marks
Short note: SSL
Short answer
SSL/TLS provides security above TCP, offering encryption, integrity, and server authentication via X.509 certificates. The handshake negotiates a cipher suite and establishes shared session keys for subsequent symmetric encryption of data, widely used in HTTPS.
Write a short note on SSL.
SSL (Secure Sockets Layer), developed by Netscape, provides security between the application layer and TCP (transport layer). Its successor is TLS (Transport Layer Security); SSL 3.0 is now obsolete, but the name SSL is still used. HTTPS = HTTP over SSL/TLS (port 443).
Services
Confidentiality (encryption), message integrity (MAC), and server (and optionally client) authentication using X.509 certificates.
Protocol structure
+-----------+--------+-----------+-----------+
| Handshake | Change | Alert | HTTP etc. |
| | Cipher | | |
+-----------+--------+-----------+-----------+
| SSL Record Protocol |
+--------------------------------------------+
| TCP |
- Handshake protocol: negotiates version and cipher suite, authenticates the server by certificate, and establishes the shared secret (pre-master secret encrypted with RSA or by Diffie-Hellman).
- Record protocol: fragments the data, compresses, adds a MAC, encrypts with the session key and sends.
- Alert protocol: reports errors or closure.
Handshake in short
- Client Hello (versions, cipher suites, random).
- Server Hello + Certificate.
- Client verifies the certificate, sends the encrypted pre-master secret.
- Both derive session keys; Finished messages are exchanged.
- Data is sent encrypted with symmetric keys.
✓ Answer checked by Claude Opus 5.5 (high effort)