| 1 | #!/usr/bin/env python |
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| 2 | |
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| 3 | import hashlib |
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| 4 | import sha256 |
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| 5 | from binascii import a2b_hex, b2a_hex |
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| 6 | |
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| 7 | class Comp4P(object): |
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| 8 | def __init__(self, h0 = None, h1 = None, text = ""): |
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| 9 | if h0 is None: |
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| 10 | self.h0 = sha256.SHA256 |
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| 11 | elif callable(h0): |
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| 12 | self.h0 = h0 |
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| 13 | else: |
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| 14 | self.h0 = lambda d='':h0.new(d) |
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| 15 | |
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| 16 | if h1 is None: |
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| 17 | self.h1 = sha256.SHA256 |
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| 18 | elif callable(h1): |
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| 19 | self.h1 = h1 |
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| 20 | else: |
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| 21 | self.h1 = lambda d='':h1.new(d) |
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| 22 | |
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| 23 | blen1 = len(self.h0().digest()) |
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| 24 | blen2 = len(self.h1().digest()) |
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| 25 | #need to preocess the different length here |
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| 26 | if blen1 > blen2 : |
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| 27 | self.blen = blen2 |
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| 28 | elif blen1 < blen2: |
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| 29 | self.blen = blen1 |
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| 30 | else: |
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| 31 | self.blen = blen1 |
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| 32 | |
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| 33 | # self.ltemp = text |
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| 34 | # self.rtemp = text |
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| 35 | |
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| 36 | self.hlins = self.h0() |
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| 37 | self.hrins = self.h1() |
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| 38 | |
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| 39 | if text != "" : |
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| 40 | self.hlins.update(text) |
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| 41 | self.hrins.update(text) |
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| 42 | |
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| 43 | def setText(self, text): |
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| 44 | # self.ltemp = text |
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| 45 | # self.rtemp = text |
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| 46 | self.hlins.update(text) |
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| 47 | self.hrins.update(text) |
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| 48 | |
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| 49 | def update(self, m): |
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| 50 | self.hlins.update(m) |
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| 51 | self.hrins.update(m) |
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| 52 | |
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| 53 | def digest(self): |
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| 54 | self.left = self.hlins.digest() |
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| 55 | self.right = self.hrins.digest() |
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| 56 | |
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| 57 | self.feistelround(self.f1) |
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| 58 | # print 'in comp', b2a_hex(self.left + self.right),'\n' |
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| 59 | self.feistelround(self.f2) |
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| 60 | # print 'in comp', b2a_hex(self.left + self.right),'\n' |
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| 61 | self.feistelround(self.f3) |
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| 62 | # print 'in comp', b2a_hex(self.left + self.right),'\n' |
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| 63 | |
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| 64 | self.result = self.right + self.left |
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| 65 | return self.result |
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| 66 | |
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| 67 | def hexdigest(self): |
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| 68 | return b2a_hex(self.digest()) |
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| 69 | |
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| 70 | def feistelround(self, f): |
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| 71 | l = self.left |
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| 72 | self.left = self.right |
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| 73 | xor1 = f(self.right) |
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| 74 | self.right = "".join(chr(ord(xor1[i]) ^ ord(l[i])) for i in xrange(self.blen)) |
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| 75 | |
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| 76 | def f1(self, m): |
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| 77 | return m |
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| 78 | |
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| 79 | def f2(self, m): |
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| 80 | msg = chr(0x02) + m |
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| 81 | a1 = self.hash0(msg) |
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| 82 | a2 = self.hash1(msg) |
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| 83 | return "".join(chr(ord(a1[i]) ^ ord(a2[i])) for i in xrange(self.blen)) |
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| 84 | |
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| 85 | def f3(self, m): |
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| 86 | msg = chr(0x03) + m |
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| 87 | a1 = self.hash0(msg) |
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| 88 | a2 = self.hash1(msg) |
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| 89 | return "".join(chr(ord(a1[i]) ^ ord(a2[i])) for i in xrange(self.blen)) |
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| 90 | |
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| 91 | def hash0(self, m): |
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| 92 | # self.h0().update(m) |
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| 93 | # return self.h0.digest() |
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| 94 | return self.h0(m).digest() |
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| 95 | |
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| 96 | def hash1(self, m): |
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| 97 | # self.h1().update(m) |
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| 98 | # return self.h1.digest() |
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| 99 | return self.h1(m).digest() |
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| 100 | |
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| 101 | def new( h0 = None, h1 = None): |
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| 102 | return Comp4P(h0, h1) |
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| 103 | |
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| 104 | |
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| 105 | |
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| 106 | |
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| 107 | |
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