De-substitution of a word
Answers to Questions
How to de-substitute a word ciphered by mono-alphabetical substitution?
Unsubstitution consists of looking at the distribution of letters in the encrypted word, specifically the repeated and distinct letters in order to make a fingerprint.
Example: XYX is decomposed: one letter, then a second letter distinct from the first one, then the first letter again
With a fingerprint (idiomorph), it is possible to search in a dictionary for words with the same fingerprint and thus corresponding to a mono-alphabetic substitution.
Example: BOB, EVE or SMS can fit, but not CAB.
dCode can not find any result if the substitution is not monoalphabetic (ie it uses a unique alphabet, such a deranged alphabet) or if the word is not present in the dictionary.
What are the most favorable cases?
The 'signature' of the word must be specific, for example, include repetitions of letters. Indeed, if there are no repeated letters, then many words can match.
Why limiting to 2 words?
The number of combinations of words is exponential and beyond the computation times exceed the minute. There are faster heuristics but they do not guarantee a result, dCode prefers to guarantee a result rather than not displaying it. To decipher a sentence, the monoalphabetic substitution tool is much faster.