Jluuis or Even Asutguus?

Have you managed to solve the entire Stage 5 Cipher Challenge? Solutions are now closed, but perhaps you want to take up the full challenge.

Successful solvers of this part were

Patrick from Woodbridge School, England
An Anonymous Solver from Somewhere in the US
Joseph from Hong Kong

The solution is:

This was a Caesar shift of seventeen followed by a transposition of rows and columns. This of course retains the letter frequencies of English, which probably helped you decipher this. In this case, the two methods of encryption commute, however this isn't always the case. Apart from some special cases, if we use a vigenere cipher and then a transposition, we will get a different result depending on which order we do them in. Can you find any cases for which these will commute?