JeremyP's Blog

The fourth challenge, the Vigenere cipher was pretty straight forward to solve. Using Singh's (well Babbage's) method on character sequences of four and five letters, I figured out the key length fairly quickly. Then, a frequency analysis of each group of letters encoded by the same key letter revealed the letter "E" in each case and from there I quckly worked out the key.

Probably the most time consuming part was writing the Vigenere decoder.