Public-Key Cryptography: Key Exchange and Signatures

This lecture covers various aspects of public-key cryptography, focusing on key exchange and digital signatures. It starts with Diffie-Hellman key exchange, RSA cryptography, and ElGamal cryptography. The case study of Signal messaging app is used to illustrate the practical application of public-key cryptography. The lecture then delves into topics like the security mechanisms of public-key cryptography, including trapdoor permutations, probabilistic encryption, and mask generation functions. It also discusses the drawbacks and benefits of different signature schemes, such as RSA, DSA, and ElGamal. The instructor, Serge Vaudenay, explains the generation of public parameters for cryptographic schemes and highlights the importance of secure key lengths and post-quantum cryptography.