Computer Networking › Section H · Security in computer networks › Topic H.2
Principles of cryptography
Cryptography lets Alice turn a message into something Trudy cannot read, using a key only the right people hold. This topic follows the idea from letter-shifting ciphers to the block ciphers, public-key systems and key agreement that protect network traffic today.
In this topic
- Keys, ciphertext and the attacker's view
- Substitution ciphers and frequency analysis
- Worked example: a Vigenère cipher
- Block ciphers: DES and AES
- Why blocks must be chained
- Public-key encryption
- Worked example: RSA with tiny numbers
- Diffie-Hellman key agreement
- Worked example: Diffie-Hellman with tiny numbers
- Session keys and the road ahead
- Common mistakes to avoid
- Key takeaways
This topic is part of Wuanberri Pro. Checking your access…