Viewing Single Post From: Double cipher challenge

Viewing Single Post From: Double cipher challenge
jdege	Aug 13 2007, 06:19 PM
Elite member Posts: 263 Group: Admin Member #246 Joined: December 7, 2006	catish10 Aug 13 2007, 11:59 AM So technically if I treat each possible alphabet as a mono substitution (keyed/random/shifted) I should be able to work out what each letter stands for with frequency/contact data etc. In the worst case, where there is no relationship between the different alphabets, you treat each as a separate simple substitution. Write out the cipheretext with one column per alphabet, and make guesses from the frequency distributions. Look for digrams and trigrams, where high-frequency letters in one alphabet occur next to high-frequency letters in an adjacent alphabet. It's tedious, but it works. If there is only the one base alphabet, and the keyword indicates shifts, then eliminating the shifts as I described before can be a faster approach. It's a short-cut for a special case, but the general method will work for it, as well.
	When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

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