Summary for Week 2

• Lecture 3:We discussed LFSRs and Geffe generators. We also covered an attack on LFSRs which illustrated how linearity should be avoided in security. We started our discussion on modern block ciphers. We covered basic principles of block cipher design (such as confusion and diffusion). We also discussed Fiestel ciphers.
  Note:Page 206 of "the handbook" describes correlation attack on Geffe generators.
  Date: Tu, 09/18/2007.
• Lecture 4: We discussed simple DES (a simplified version of DES) in detail. After that we briefly discussed DES. We started discussing modes of operations. We covered two modes (ECB and CBC).
  Date:Th, 09/20/2007.