25 lines
477 B
Python
25 lines
477 B
Python
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def rc4_ksa(key):
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n = len(key)
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j = 0
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s_box = list(range(256))
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for i in range(256):
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j = (j + s_box[i] + key[i % n]) % 256
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s_box[i], s_box[j] = s_box[j], s_box[i]
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return s_box
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def rc4_prga(s_box):
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i = 0
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j = 0
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while True:
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i = (i + 1) % 256
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j = (j + s_box[i]) % 256
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s_box[i], s_box[j] = s_box[j], s_box[i]
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yield s_box[(s_box[i] + s_box[j]) % 256]
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def rc4(key):
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return rc4_prga(rc4_ksa(key))
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