Summary for Week 9

• Lecture 16: We finished our discussion on meet-in-the-middle attack on 2DES. We discussed 3DES and reasoned why the attack on 2DES does not work for 3DES. We started covering number theory we need for public-key cryptography. We covered Z_n and Z_n^* and the Euler's algorithm to compute GCDs. We also covered phi-function, which is the size of Z_n^*.
  Required reading: Chapter 3 (section 5.4) and the number-theory handout.
  Date:Tu, 10/30/12.
• Lecture 17: We finished our discussion on number-theory basics. We covered the structure of Z_p^* (it is a cyclic group), Fermat's little theorem (FLT), and the Chinese Remainder Theorem (CRT).
  Required reading: The number-theory handout.
  Date:Th, 1/1/12.