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43 lines
1.7 KiB
43 lines
1.7 KiB
6 years ago
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import requests
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from binascii import unhexlify
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# get the list of strings (each string is 60 characters)
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request = requests.get('https://cryptopals.com/static/challenge-data/4.txt')
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requestArray = request.text.splitlines()
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# here's the code used in challenge 3, which is said to be useful
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def xor_SingleByte(hexed):
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alphabet = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
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unHexed = unhexlify(hexed)
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# generate a dict of possible answers and their decryption keys
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tableOfPossibleAnswers = {}
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for code in range(256):
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possibleAnswer = ''.join(chr(byte ^ code) for byte in unHexed)
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if possibleAnswer.isprintable():
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tableOfPossibleAnswers[code] = possibleAnswer
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# weight the answers using a simple english alphabet list
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if tableOfPossibleAnswers:
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weightedCodes = {}
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for key,value in tableOfPossibleAnswers.items():
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weightedCodes[value] = 0
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for letter in alphabet:
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if letter in value:
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weightedCodes[value] += 1
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# find the highest value and return it and its corresponding key
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maxValue = max(weightedCodes.values())
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answerValue = []
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for key in weightedCodes:
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if weightedCodes[key] == maxValue:
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answerValue = key
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# now i need to use that to key into the original tableOfPossibleAnswers to return the answer and the decryption key.
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for key,value in tableOfPossibleAnswers.items():
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if tableOfPossibleAnswers[key] == answerValue:
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print(key, tableOfPossibleAnswers[key])
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for string in requestArray:
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xor_SingleByte(string)
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