CNS06 Midterm part 1   (Revised 10/1/06)


Answer the following questions on the MISTY1 cipher.  Email answers or give me
your hardcopy (with your name on it) by the start of class next week (10/10/06).
You can use textbook, web, etc. but work on your own! Be brief but thorough.  
Use the references on the class 7 (midterm) class web page.

Number in parentheses is point value.
AES refers to Rijndael.

(24) 1. A tablular comparison of MISTY1, DES, and AES-128.
        Fill in the following table.

                                  DES              AES           MISTY1
block size (bits)                  64              128              64
key size (bits)
number of rounds/steps
wordsize (bits)
round operators (names,e.g add)
number of subkeys
size of a subkey (bits)
Feistel (Y/N)
number of S boxes



( 6) 2. What are the sources of strength and non-linearity for MISTY1?




( 6) 3. Compare/contrast the mechanisms for generating subkeys for MISTY1,
        DES, and AES.






( 6) 4. Comment on how the contents of the S-boxes were derived for
        AES, DES, and MISTY1.







( 6) 6. Comment on the strength of MISTY1, e.g. weak keys, strength
        against differential cryptanalysis, key size.