pymd5.py

#/* Constants for MD5Transform routine.

S11 = 7
S12 = 12
S13 = 17
S14 = 22
S21 = 5
S22 = 9
S23 = 14
S24 = 20
S31 = 4
S32 = 11
S33 = 16
S34 = 23
S41 = 6
S42 = 10
S43 = 15
S44 = 21

PADDING = "\x80" + 63*"\0"   # do not overlook first byte again :-)

#/* F, G, H and I are basic MD5 functions.
def F(x, y, z): return (((x) & (y)) | ((~x) & (z)))

def G(x, y, z): return (((x) & (z)) | ((y) & (~z)))

def H(x, y, z): return ((x) ^ (y) ^ (z))

def I(x, y, z): return((y) ^ ((x) | (~z)))

#/* ROTATE_LEFT rotates x left n bits.

def ROTATE_LEFT(x, n):
    x = x & 0xffffffffL   # make shift unsigned
    return (((x) << (n)) | ((x) >> (32-(n)))) & 0xffffffffL

#/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
#Rotation is separate from addition to prevent recomputation.

def FF(a, b, c, d, x, s, ac):
    a = a + F ((b), (c), (d)) + (x) + (ac)
    a = ROTATE_LEFT ((a), (s))
    a = a + b
    return a # must assign this to a

def GG(a, b, c, d, x, s, ac):
    a = a + G ((b), (c), (d)) + (x) + (ac)
    a = ROTATE_LEFT ((a), (s))
    a = a + b
    return a # must assign this to a

def HH(a, b, c, d, x, s, ac):
    a = a + H ((b), (c), (d)) + (x) + (ac)
    a = ROTATE_LEFT ((a), (s))
    a = a + b
    return a # must assign this to a

def II(a, b, c, d, x, s, ac):
    a = a + I ((b), (c), (d)) + (x) + (ac)
    a = ROTATE_LEFT ((a), (s))
    a = a + b
    return a # must assign this to a


class md5:
    def __init__(self, initial=None):
        self.count = 0L
        self.state = (0x67452301L,
                      0xefcdab89L,
                      0x98badcfeL,
                      0x10325476L,)
        self.buffer = ""
        if initial:
            self.update(initial)

##/* MD5 block update operation. Continues an MD5 message-digest
##  operation, processing another message block, and updating the
##  context.
## */

##  /* Compute number of bytes mod 64 */
    def update(self, input):
        inputLen = len(input)
##  index = (unsigned int)((context->count[0] >> 3) & 0x3F);
        index = int(self.count >> 3) & 0x3F

##  /* Update number of bits */
        self.count = self.count + (inputLen << 3)

##  partLen = 64 - index;
        partLen = 64 - index

##  /* Transform as many times as possible.
        if inputLen >= partLen:
            self.buffer = self.buffer[:index] + input[:partLen]
            self.transform(self.buffer)
            i = partLen
            while i + 63 < inputLen:
                self.transform(input[i:i+64])
                i = i + 64
            index = 0
        else:
            i = 0

##  /* Buffer remaining input */
        self.buffer = self.buffer[:index] + input[i:inputLen]
        

##/* MD5 finalization. Ends an MD5 message-digest operation, writing the
##  the message digest and zeroizing the context.
## */
        
    def final(self):

##  /* Save number of bits */
        bits = Encode((self.count & 0xffffffffL, self.count>>32), 8)
            
##  /* Pad out to 56 mod 64.

        index = int((self.count >> 3) & 0x3f)
        if index < 56:
            padLen = (56 - index)
        else:
            padLen = (120 - index)
        self.update(PADDING[:padLen])

##  /* Append length (before padding) */
        self.update(bits)

##  /* Store state in digest */
        digest = Encode(self.state, 16)

##  /* Zeroize sensitive information.

        self.__dict__.clear()

        return digest
    
    digest = final  # alias

##/* MD5 basic transformation. Transforms state based on block.
## */

    def transform(self, block):
        a, b, c, d = state = self.state

        x = Decode(block, 64)

##  /* Round 1 */
        a = FF (a, b, c, d, x[ 0], S11, 0xd76aa478)#; /* 1 */
        d = FF (d, a, b, c, x[ 1], S12, 0xe8c7b756)#; /* 2 */
        c = FF (c, d, a, b, x[ 2], S13, 0x242070db)#; /* 3 */
        b = FF (b, c, d, a, x[ 3], S14, 0xc1bdceee)#; /* 4 */
        a = FF (a, b, c, d, x[ 4], S11, 0xf57c0faf)#; /* 5 */
        d = FF (d, a, b, c, x[ 5], S12, 0x4787c62a)#; /* 6 */
        c = FF (c, d, a, b, x[ 6], S13, 0xa8304613)#; /* 7 */
        b = FF (b, c, d, a, x[ 7], S14, 0xfd469501)#; /* 8 */
        a = FF (a, b, c, d, x[ 8], S11, 0x698098d8)#; /* 9 */
        d = FF (d, a, b, c, x[ 9], S12, 0x8b44f7af)#; /* 10 */
        c = FF (c, d, a, b, x[10], S13, 0xffff5bb1)#; /* 11 */
        b = FF (b, c, d, a, x[11], S14, 0x895cd7be)#; /* 12 */
        a = FF (a, b, c, d, x[12], S11, 0x6b901122)#; /* 13 */
        d = FF (d, a, b, c, x[13], S12, 0xfd987193)#; /* 14 */
        c = FF (c, d, a, b, x[14], S13, 0xa679438e)#; /* 15 */
        b = FF (b, c, d, a, x[15], S14, 0x49b40821)#; /* 16 */

## /* Round 2 */
        a = GG (a, b, c, d, x[ 1], S21, 0xf61e2562)#; /* 17 */
        d = GG (d, a, b, c, x[ 6], S22, 0xc040b340)#; /* 18 */
        c = GG (c, d, a, b, x[11], S23, 0x265e5a51)#; /* 19 */
        b = GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa)#; /* 20 */
        a = GG (a, b, c, d, x[ 5], S21, 0xd62f105d)#; /* 21 */
        d = GG (d, a, b, c, x[10], S22,  0x2441453)#; /* 22 */
        c = GG (c, d, a, b, x[15], S23, 0xd8a1e681)#; /* 23 */
        b = GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8)#; /* 24 */
        a = GG (a, b, c, d, x[ 9], S21, 0x21e1cde6)#; /* 25 */
        d = GG (d, a, b, c, x[14], S22, 0xc33707d6)#; /* 26 */
        c = GG (c, d, a, b, x[ 3], S23, 0xf4d50d87)#; /* 27 */
        b = GG (b, c, d, a, x[ 8], S24, 0x455a14ed)#; /* 28 */
        a = GG (a, b, c, d, x[13], S21, 0xa9e3e905)#; /* 29 */
        d = GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8)#; /* 30 */
        c = GG (c, d, a, b, x[ 7], S23, 0x676f02d9)#; /* 31 */
        b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8a)#; /* 32 */

##  /* Round 3 */
        a = HH (a, b, c, d, x[ 5], S31, 0xfffa3942)#; /* 33 */
        d = HH (d, a, b, c, x[ 8], S32, 0x8771f681)#; /* 34 */
        c = HH (c, d, a, b, x[11], S33, 0x6d9d6122)#; /* 35 */
        b = HH (b, c, d, a, x[14], S34, 0xfde5380c)#; /* 36 */
        a = HH (a, b, c, d, x[ 1], S31, 0xa4beea44)#; /* 37 */
        d = HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9)#; /* 38 */
        c = HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60)#; /* 39 */
        b = HH (b, c, d, a, x[10], S34, 0xbebfbc70)#; /* 40 */
        a = HH (a, b, c, d, x[13], S31, 0x289b7ec6)#; /* 41 */
        d = HH (d, a, b, c, x[ 0], S32, 0xeaa127fa)#; /* 42 */
        c = HH (c, d, a, b, x[ 3], S33, 0xd4ef3085)#; /* 43 */
        b = HH (b, c, d, a, x[ 6], S34,  0x4881d05)#; /* 44 */
        a = HH (a, b, c, d, x[ 9], S31, 0xd9d4d039)#; /* 45 */
        d = HH (d, a, b, c, x[12], S32, 0xe6db99e5)#; /* 46 */
        c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8)#; /* 47 */
        b = HH (b, c, d, a, x[ 2], S34, 0xc4ac5665)#; /* 48 */

##  /* Round 4 */
        a = II (a, b, c, d, x[ 0], S41, 0xf4292244)#; /* 49 */
        d = II (d, a, b, c, x[ 7], S42, 0x432aff97)#; /* 50 */
        c = II (c, d, a, b, x[14], S43, 0xab9423a7)#; /* 51 */
        b = II (b, c, d, a, x[ 5], S44, 0xfc93a039)#; /* 52 */
        a = II (a, b, c, d, x[12], S41, 0x655b59c3)#; /* 53 */
        d = II (d, a, b, c, x[ 3], S42, 0x8f0ccc92)#; /* 54 */
        c = II (c, d, a, b, x[10], S43, 0xffeff47d)#; /* 55 */
        b = II (b, c, d, a, x[ 1], S44, 0x85845dd1)#; /* 56 */
        a = II (a, b, c, d, x[ 8], S41, 0x6fa87e4f)#; /* 57 */
        d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0)#; /* 58 */
        c = II (c, d, a, b, x[ 6], S43, 0xa3014314)#; /* 59 */
        b = II (b, c, d, a, x[13], S44, 0x4e0811a1)#; /* 60 */
        a = II (a, b, c, d, x[ 4], S41, 0xf7537e82)#; /* 61 */
        d = II (d, a, b, c, x[11], S42, 0xbd3af235)#; /* 62 */
        c = II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb)#; /* 63 */
        b = II (b, c, d, a, x[ 9], S44, 0xeb86d391)#; /* 64 */

        self.state = (0xffffffffL & (state[0] + a),
                      0xffffffffL & (state[1] + b),
                      0xffffffffL & (state[2] + c),
                      0xffffffffL & (state[3] + d),)

##  /* Zeroize sensitive information.

        del x

# end of the class. Now the helpers

import struct, string

def Encode(input, len):
    k = len >> 2
    res = apply(struct.pack, ("%iI" % k,) + tuple(input[:k]))
    return string.join(res, "")

def Decode(input, len):
    k = len >> 2
    res = struct.unpack("%iI" % k, input[:len])
    return list(res)

def test():
    print `md5("hallo").digest()`
    from md5 import new
    print `new("hallo").digest()`

if __name__=="__main__":
    test()