56 lines
1.2 KiB
Python
Executable File
56 lines
1.2 KiB
Python
Executable File
#!/usr/bin/python3
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import math
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def totient(p, q):
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tot, rem = divmod((p-1) * (q-1), math.gcd(p-1, q-1))
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if rem != 0:
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raise Exception("totient calc failed")
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return tot
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def egcd(a, b):
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x0, x1, y0, y1 = 0, 1, 1, 0
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while a != 0:
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(q, a), b = divmod(b, a), a
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y0, y1 = y1, y0 - q * y1
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x0, x1 = x1, x0 - q * x1
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return b, x0, x1
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# https://en.wikibooks.org/wiki/Algorithm_Implementation/Mathematics/Extended_Euclidean_algorithm
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def mod_inv(d, lambda_n):
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g, x, _ = egcd(d, lambda_n)
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if g != 1:
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raise Exception("gcd(d, lambda_n != !")
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return x % lambda_n
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def rsa(text, key, n):
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return pow(text, key, n)
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with open("values", 'r') as f:
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lines = f.readlines()
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C = int(lines[1][3:])
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n = int(lines[2][3:])
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e = int(lines[3][3:])
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p = int(lines[4][3:])
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q = int(lines[5][3:])
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if p*q == n:
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print("factoring correct")
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else:
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print("factoring incorrect")
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lambda_n = totient(p, q)
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d = mod_inv(e, lambda_n)
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#d = pow(d, -1, lambda_n)
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res = rsa(C, d, n)
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text = ''
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while (char := (res % 256)) != 0:
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text = chr(char) + text;
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res >>= 8
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print(text)
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