MATH/CMSC 456, Spring 2010

Info about Exam #1

Calculators are allowed, and might save you a bit of time, though they are not necessary. Topics covered on this test are:

• Shift, affine, Hill, and Vigenère ciphers (all using arithmetic in Z₂₆)
• Substitution ciphers, frequency analysis (also how it is used to break Vigenère)
• The one-time pad and Shannon's theorem
• Kinds of attacks on cryptosystems:
• ciphertext only
• known plaintext
• chosen ciphertext
• chosen plaintext
• Ch. 3 on basic number theory:
• extended Euclidean algorithm and gcd
• Chinese remainder theorem, linear congruences
• quadratic congruences
• computing the Legendre symbol
• Basic facts about block ciphers
• Feistel systems
• Meet-in-the-middle attacks against multiple encryption