72 lines
2.3 KiB
Python
72 lines
2.3 KiB
Python
'''
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Created on May 23, 2020
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@author: cvkennedy
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'''
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from itertools import combinations
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import matplotlib.pyplot as plt
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import numpy as np
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def find_outliers(corpus, num_samps, i, j):
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idxs = corpus[i][j].argsort()[:num_samps]
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return idxs
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def guess_bytes(corpus, known_keybytes, num_samps, avg):
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candidates = []
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for base in range(4):
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family = [base, base + 4, base + 8, base + 12]
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for combo in combinations(family, 2):
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i,j = combo
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guesses = find_outliers(corpus, num_samps, i, j)
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guesses2 = []
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for guess in guesses:
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cnt = corpus[i][j][guess]
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if cnt-avg < -10:
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guesses2.append((i, j, guess, cnt-avg))
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print(i, j, guess, cnt - avg)
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candidates.append(tuple(guesses2))
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print(candidates)
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if __name__ == '__main__':
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known_keybytes = bytes.fromhex("64c7072487f2")
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secret_data = ("c1a5fe7beb2c70bfab98926627dcff8b9671edc5" +
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"2441f89fa47797aa023f15f67907ee837b93cd9b" +
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"194922ebb7c3ca3bd1cbfbc888efe147e8055404" +
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"7d82872fcee564c1bfd2e0a809568acb5cc08f48" +
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"36a5f91f43b576a4ee1c6f097c15e1cd4056917f" +
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"c51c1e5d8157409b11f1600d")
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data = set()
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with open("test.txt", "r") as fp:
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for line in fp:
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pt, timing = line.strip().split(',')
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pt = bytes.fromhex(pt)
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timing = int(timing)
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data.add((pt, timing))
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tavg = sum((d[1] for d in data)) / len(data)
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print("tavg: %d" % tavg)
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known_tly = np.zeros((16, 16, 256))
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for base in range(4):
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print("Building corpus for family %d" % base)
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family = [base, base + 4, base + 8, base + 12]
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for combo in combinations(family, 2):
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times = np.zeros(256)
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counts = np.zeros(256)
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i,j = combo
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print("Working on %d, %d" % (i, j))
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for d in data:
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n = d[0][i] ^ d[0][j]
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c = d[1]
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times[n] += c
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counts[n] += 1
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for c in range(256):
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cnorm = times[c] / counts[c]
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known_tly[i][j][c] = cnorm
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known_tly[j][i][c] = cnorm
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guess_bytes(known_tly, known_keybytes, 4, tavg)
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