Криптоанализ Python

>>> txt='''While the images document people who live on the edges, outside of the mainstream, there is never a sense of voyeurism, or exploitation. “For some of the artists and bodies of work we’re showing, it’s about their own personal participation in those worlds,” says Pardo. “Others have managed to get through the door, they were outsiders but they become insiders, at least for a certain amount of time in order for their subjects to begin to trust them and to feel comfortable. But whether it’s temporarily or permanently, they all begin to live as one with these communities.”'''
>>> from collections import Counter
>>> c = Counter(txt)
>>> summ = sum(c.values())
>>> for i in c:
    c[i] = c[i]/summ
>>> c
Counter({' ': 0.16869565217391305, 'e': 0.11304347826086956, 't': 0.08869565217391304, 'o': 0.08, 'i': 0.057391304347826085, 'r': 0.057391304347826085, 's': 0.05565217391304348, 'a': 0.04695652173913043, 'h': 0.04173913043478261, 'n': 0.04173913043478261, 'm': 0.02782608695652174, 'l': 0.02434782608695652, 'd': 0.022608695652173914, 'u': 0.020869565217391306, 'w': 0.01565217391304348, 'f': 0.01565217391304348, 'g': 0.01391304347826087, 'p': 0.01391304347826087, ',': 0.01391304347826087, 'b': 0.01391304347826087, 'c': 0.01217391304347826, 'y': 0.01217391304347826, 'v': 0.008695652173913044, '.': 0.006956521739130435, '’': 0.0052173913043478265, '“': 0.0034782608695652175, '”': 0.0034782608695652175, 'W': 0.0017391304347826088, 'x': 0.0017391304347826088, 'F': 0.0017391304347826088, 'k': 0.0017391304347826088, 'P': 0.0017391304347826088, 'O': 0.0017391304347826088, 'j': 0.0017391304347826088, 'B': 0.0017391304347826088})
>>>