- Numbers can and have been reused in cipher one, especially for the...
- ...high numbers, which often refer to letters that rarely begin English words
This sometimes forces person encrypting text to reuse rare letter numbers when extras aren't available in text used as cipher > Vulnerable
- First text presents language which might reappear in text two and three
One system I am building, will pass words that are likely to reappear through text, to see if partial words form from number reuse. Ex words: buried, excavation, silver, gold, bufords, vault, etc. all of which appear in text one
- Another method of frequency analysis could be to specifically target the high numbers
Replace them with uncommon letters, if I am able to hit something like a 'q' then apply the previously mentioned method of passing words through, the text could begin to unwravel
- As we know the encryption method uses a book for encrypting the text, one could look for a book with words that begin with uncommon letters at the really high numbers, with consideration to what books one might have access to given the period in time and geographical location