Cryptography Basics
Modern cryptography secures data and communications. Learn core building blocks and how they combine into secure protocols.
📚 Building Blocks
- Symmetric ciphers: AES for confidentiality
- Public-key crypto: RSA/ECC for key exchange and signatures
- Hashes: SHA-2/3 for integrity; HMAC for MACs
- AEAD: GCM/ChaCha20-Poly1305 for encryption+auth
❓ Frequently Asked Questions
1) Why not roll my own crypto?
Subtle flaws are common; use vetted libraries.
Subtle flaws are common; use vetted libraries.
2) RSA vs ECC?
ECC achieves similar security with smaller keys and faster operations.
ECC achieves similar security with smaller keys and faster operations.
3) Perfect secrecy?
One-time pad is ideal but impractical due to key distribution.
One-time pad is ideal but impractical due to key distribution.
4) Forward secrecy?
Ephemeral key exchange prevents past session decryption if keys leak.
Ephemeral key exchange prevents past session decryption if keys leak.
5) Quantum threat?
Shor's algorithm breaks RSA/ECC; post-quantum schemes are emerging.
Shor's algorithm breaks RSA/ECC; post-quantum schemes are emerging.