Homeworks (solutions have been taken off-line)

1. Homework 1
   • Homework 1, and letter frequencies and the ciphertext for problem 1. A longer ciphertext is also available.
   • Solutions
2. Homework 2
   • Homework 2
     (Clarification: In problems 4 and 5 the syntax of encryption (that we have been using all along) is not being changed. Encryption takes only a key and a single message, and outputs a ciphertext. In particular, when you encrypt the first message m, you do not know m' (you don't even know there will be an m'!), and, since there is no state, even when you encrypt the second message m' you don't know remember what m was.)
   • Solutions
3. Homework 3
   • Homework 3
   • Solutions
4. Homework 4
   • Homework 4
   • Solutions
5. Homework 5
   • Homework 5 and the block cipher code
     Note: You do not need to do question 3, since we did not cover this material in class.
   • Solutions
6. Homework 6
   • Homework 6
   • Solutions
7. Homework 7
   • Homework 7
     Note: For Exercise 10.14, assume the message has length exactly |N|/2
     Note: For Exercise 10.17(c), you do not need to provide any definiton or proof
   • Solutions