332 http://inventwithpython.com/hacking

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231. print('Kasiski Examination results say the most likely key lengths
     are: ' + keyLengthStr + '\n')


232. 
     


233. for keyLength in allLikelyKeyLengths:


234. if not SILENT_MODE:


235. print('Attempting hack with key length %s (%s possible
     keys)...' % (keyLength, NUM_MOST_FREQ_LETTERS ** keyLength))


236. hackedMessage = attemptHackWithKeyLength(ciphertext, keyLength)


237. if hackedMessage != None:


238. break


239. 
     


240. 
     

     If none of the key lengths we found using Kasiski Examination

     
     


241. 
     

     worked, start brute-forcing through key lengths.

     
     


242. if hackedMessage == None:


243. if not SILENT_MODE:


244. print('Unable to hack message with likely key length(s).
     Brute-forcing key length...')


245. for keyLength in range(1, MAX_KEY_LENGTH + 1):


246. 
     

     don't re-check key lengths already tried from Kasiski

     
     


247. if keyLength not in allLikelyKeyLengths:


248. if not SILENT_MODE:


249. print('Attempting hack with key length %s (%s possible
     keys)...' % (keyLength, NUM_MOST_FREQ_LETTERS ** keyLength))


250. hackedMessage = attemptHackWithKeyLength(ciphertext,
     keyLength)


251. if hackedMessage != None:


252. break


253. return hackedMessage


254. 
     


255. 
     


256. 
     

     If vigenereHacker.py is run (instead of imported as a module) call

     
     


257. 
     

     the main() function.

     
     


258. if name == 'main':


259. main()

Sample Run of the Vigenère Hacking Program

When you run the vigenereHacker.py program, the output will look like this:

Kasiski Examination results say the most likely key lengths are: 3 2 6 4 12

Attempting hack with key length 3 (27 possible keys)...
Possible letters for letter 1 of the key: A L M
Possible letters for letter 2 of the key: S N O
Possible letters for letter 3 of the key: V I Z