Implementing-cryptography-using-python

Chapter 4 ■ Cryptographic Math and Frequency Analysis 127
and if the words are not readable in English, you can start swapping the most
common letters with the frequency key of letters produced by the following code:
import urllib.request, random, ssl
import operator
def getLetterFreqs(text):
frequency = {}
for ascii in range(ord('a'), ord('a')+26):
frequency[chr(ascii)] = float(text.count(chr(ascii)))/len(text)
sum_freqs_squared = 0.0
for ltr in frequency:
sum_freqs_squared += frequency[ltr]*frequency[ltr]
return sum_freqs_squared
def getFitnessScore(message):
lower = message.lower()
score = 0.0
for word in longerwords:
wordWeight = lower.count(word)
if wordWeight>0:
score += wordWeight * 50 * len(word)
return score
def getFreqKey(text):
frequency = {}
message = text.lower()
normal_freqs = {'a': 0.080642499002080981, 'c': 0.026892340312538593, 'b':
0.015373768624831691, 'e': 0.12886234260657689, 'd': 0.043286671390026357, 'g':
0.019625534749730816, 'f': 0.024484713711692099, 'i': 0.06905550211598431, 'h':
0.060987267963718068, 'k': 0.0062521823678781188, 'j': 0.0011176940633901926, 'm':
0.025009719347800208, 'l': 0.041016761327711163, 'o': 0.073783151266212627, 'n':
0.069849754102356679, 'q': 0.0010648594165322703, 'p': 0.017031440203182008, 's':
0.063817324270355996, 'r': 0.06156572691936394, 'u': 0.027856851020401599, 't':
0.090246649949305979, 'w': 0.021192261444145363, 'v': 0.010257964235274787, 'y':
0.01806326249861108, 'x': 0.0016941732664605912, 'z': 0.0009695838238376564}
tolerance = .013
for ascii in range(ord('a'), ord('a')+26):
frequency[chr(ascii)] = message.count(chr(ascii))
sorted_x = sorted(frequency.items(), key=operator.itemgetter(1),
reverse=True)
print (sorted_x)
sortedkey = ""