Week 6

02/26/2008 (Tu, Lecture 8): We discussed a signature scheme based on RSA and then
described authenticated Diffie-Hellman key exchange protocol which addresses the MITM
attack described earlier. We also discussed the concept of blind signatures based on RSA. We started discussing hash functions and described some requirements of hash functions, such as one-way and weak collision resistance.

02/28/2006 (Th, Lecture 9): We discussed the random-oracle model of hash functions and
then used it to prove the "ciphertext indistinguishability" property of a public-key crypto-system based on RSA. We also discussed hash-chains and Merkle hash trees. We discussed the basic architecture of an iterated hash function. We covered a specific
hash function called MD5.