40 lines
1014 B
Python
40 lines
1014 B
Python
"""Pure-Python RC4 implementation."""
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from RC4 import RC4
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from cryptomath import *
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def new(key):
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return Python_RC4(key)
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class Python_RC4(RC4):
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def __init__(self, key):
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RC4.__init__(self, key, "python")
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keyBytes = stringToBytes(key)
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S = [i for i in range(256)]
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j = 0
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for i in range(256):
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j = (j + S[i] + keyBytes[i % len(keyBytes)]) % 256
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S[i], S[j] = S[j], S[i]
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self.S = S
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self.i = 0
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self.j = 0
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def encrypt(self, plaintext):
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plaintextBytes = stringToBytes(plaintext)
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S = self.S
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i = self.i
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j = self.j
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for x in range(len(plaintextBytes)):
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i = (i + 1) % 256
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j = (j + S[i]) % 256
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S[i], S[j] = S[j], S[i]
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t = (S[i] + S[j]) % 256
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plaintextBytes[x] ^= S[t]
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self.i = i
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self.j = j
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return bytesToString(plaintextBytes)
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def decrypt(self, ciphertext):
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return self.encrypt(ciphertext)
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