cs212 A Caesar cipher is an encryption scheme based on cycli

cs212

A Caesar cipher is an encryption scheme based on cyclic permutations of the alphabet, with the i-th letter of the alphabet replaced by the (i + n)-th letter of the alphabet. For example, in a Caesar cipher with a shift of 4, \"Caesar\" would be encrypted as \"Geiger.\" Give three heuristics that might be used for solving Caesar ciphers. In a simple substitution cipher, each letter is replaced by another letter under some arbitrary one-to-one mapping. Which of the heuristics proposed for the Caesar cipher may be used to solve substitution ciphers? Explain. (Thanks to Don Morrison for this problem.)

Solution

(1) Trying all possible 25 keys

(2) Using frequency analysis, E is the most frequent letter in English, and so we map the most frequent letter in the ciphered text to E and then find the key ... etc.

Now I want to find another heuristic that can be used to solve Caesar cipher, I don\'t need it to be more efficient, I just want it to work. I mean, I want another heuristic (Algorithm) to solve Caesar cipher, and I don\'t care whether it\'s efficient or not.

(3) I think a third heuristic could be using the trigram frequency and the most frequent trigram is \"the\". The good thing about this trigram is that it covers both the most frequent letter and bigram in English language.