Exam 3: Block Ciphers and the Data Encryption Standard

The key schedule algorithm is more popular and has received more attention than S-box design.

Feistel's is a practical application of a proposal by Claude Shannon to develop a product cipher that alternates confusion and ________ functions.

The strict avalanche criterion and the bit independence criterion appear to weaken the effectiveness of the confusion function.

Fast software encryption/decryption and ease of analysis are two considerations in the design of a Feistel cipher.

One criteria for an S-box is: "If two inputs to an S-box differ in exactly one bit,the outputs must also differ in exactly one bit."

An advantage of key-dependent S-boxes is that because they are not fixed,it is impossible to analyze the S-boxes ahead of time to look for weaknesses.

The __________ criterion states that output bits j and k should change independently when any single input bit i is inverted for all i,j and k.