Dr. Jaffe
Advanced Topics in Mathematics
Homework due Monday 12/ 21
NAME: ________________________________________________
1. If the two most common letters in a long ciphertext, enciphered by an affine transformation C ≡ aP + b (mod 26)
are W and B, respectively, then what are the most likely values of a and b?
2. If the two most common letters in a long ciphertext, enciphered by an affine transformation C ≡ aP + b (mod 26)
are X and Q, respectively, then what are the most likely values of a and b?
3. The message
WEZBF
TBBNJ
THNBT
ADZOE
TGTYR
ANOOZ
ABOVG
FNWZV
A
ATWGN
BZAJN
was encrypted using an affine transformation C ≡ aP + b (mod 26). The most common letters in the plaintext are A,
E, N, and S. What is the plaintext message?
4. Decrypt the message
C ≡ 21P + 5 (mod 26).
YLFQX
P C R I T, which was encrypted using the affine transformation