CSE 651 Homework 2

CSE 651 Homework 2 - 1 IP is the inverse initial...

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CSE 651 Homework 2 Due: Monday, April 19 by class time 1. Do Problem 3.2 of Stallings. (Hints: (1) The information about 128-bit block size and key length is not important. (2) Imagine that there is an oracle who can encrypt one message of your choice for you; this question asks how you can make use of this oracle to decrypt your ciphertext c.) 2. Do Problem 3.7 of Stallings. Hints: (1) in the 4 th edition, the symbol in the question should be , XOR; this has been corrected in the 5 th edition. (2) The function computed by the modified DES is: 1 IP IP( ) m  , where m is a plaintext block, is the swap function defined in class, IP is the initial permutation,
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Unformatted text preview: 1 IP is the inverse initial permutation, is the 16 rounds. Here you need to figure out the function . You should not simply answer that 16 2 1 . 3. Do Problem 3.12 of Stallings. In addition to specifying a table analogous to Table 3.4d, you need to indicate whether to rotate to the left or to the right. 4. Consider AES. (a) Suppose we change one bit in the first byte of the input block. After the first round of AES, how many bits of the output matrix state are possibly affected? (b) Answer the same question but now we change one bit in the last byte of the input block....
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