Decrypt the following message that was encrypted using: Caesar’s cipher: WHVWWRGDB

Question

Decrypt the following message that was encrypted using: (a) Caesar’s cipher: WHVWWRGDB

I'm told to decrypt the message using Ceasar's cipher but they don't tell me the key shift so how in the world am I supposed to decrypt the message? Am I missing something obvious here? Any help would be great

Answer 1

Didn't have to do any of that stuff, just read somewhere that ceaser cipher commonly uses shifts of $3$ and then i subtracted 3 from each and came up with the message Test Today

Answer 2

Do frequency analysis. For example W is the letter which appears the most in the ciphertext so perhaps it corresponds to the letter "e" in the plaintext. If this works then V must be replacement for...... if this doesn;t work then try another letter (see frequency of letters in English alphabet)

Answer 3

A frequency analysis is quite likely to tell you very little with such a short message. The most efficient approach is simply to try the $25$ possible shifts: most of them will very quickly reveal themselves as impossible. Here are the first few:

$$\begin{array}{ccc} W&H&V&W&W&R&G&D&B\\ X&I&W\\ Y&J\\ Z&K\\ A&L&Z&A&A\\ B&M\\ C&N\\ D&O&C&D&D\\ \end{array}$$

You’ll get there much faster if you work backwards through the shifts, though.