## Python, , md5.py

``````import math

def rearrange(bitString32):
"""[summary]
Regroups the given binary string.

Arguments:
bitString32 {[string]} -- [32 bit binary]

Raises:
ValueError -- [if the given string not are 32 bit binary string]

Returns:
[string] -- [32 bit binary string]
>>> rearrange('1234567890abcdfghijklmnopqrstuvw')
'pqrstuvwhijklmno90abcdfg12345678'
"""

if len(bitString32) != 32:
raise ValueError("Need length 32")
newString = ""
for i in [3, 2, 1, 0]:
newString += bitString32[8 * i : 8 * i + 8]
return newString

def reformatHex(i):
"""[summary]
Converts the given integer into 8-digit hex number.

Arguments:
i {[int]} -- [integer]
>>> reformatHex(666)
'9a020000'
"""

hexrep = format(i, "08x")
thing = ""
for i in [3, 2, 1, 0]:
thing += hexrep[2 * i : 2 * i + 2]
return thing

"""[summary]
Fills up the binary string to a 512 bit binary string

Arguments:
bitString {[string]} -- [binary string]

Returns:
[string] -- [binary string]
"""
startLength = len(bitString)
bitString += "1"
while len(bitString) % 512 != 448:
bitString += "0"
lastPart = format(startLength, "064b")
bitString += rearrange(lastPart[32:]) + rearrange(lastPart[:32])
return bitString

def getBlock(bitString):
"""[summary]
Iterator:
Returns by each call a list of length 16 with the 32 bit
integer blocks.

Arguments:
bitString {[string]} -- [binary string >= 512]
"""

currPos = 0
while currPos < len(bitString):
currPart = bitString[currPos : currPos + 512]
mySplits = []
for i in range(16):
mySplits.append(int(rearrange(currPart[32 * i : 32 * i + 32]), 2))
yield mySplits
currPos += 512

def not32(i):
"""
>>> not32(34)
4294967261
"""
i_str = format(i, "032b")
new_str = ""
for c in i_str:
new_str += "1" if c == "0" else "0"
return int(new_str, 2)

def sum32(a, b):
return (a + b) % 2**32

def leftrot32(i, s):
return (i << s) ^ (i >> (32 - s))

def md5me(testString):
"""[summary]
Returns a 32-bit hash code of the string 'testString'

Arguments:
testString {[string]} -- [message]
"""

bs = ""
for i in testString:
bs += format(ord(i), "08b")

tvals = [int(2**32 * abs(math.sin(i + 1))) for i in range(64)]

a0 = 0x67452301
b0 = 0xEFCDAB89
d0 = 0x10325476

s = [
7,
12,
17,
22,
7,
12,
17,
22,
7,
12,
17,
22,
7,
12,
17,
22,
5,
9,
14,
20,
5,
9,
14,
20,
5,
9,
14,
20,
5,
9,
14,
20,
4,
11,
16,
23,
4,
11,
16,
23,
4,
11,
16,
23,
4,
11,
16,
23,
6,
10,
15,
21,
6,
10,
15,
21,
6,
10,
15,
21,
6,
10,
15,
21,
]

for m in getBlock(bs):
A = a0
B = b0
C = c0
D = d0
for i in range(64):
if i <= 15:
# f = (B & C) | (not32(B) & D)
f = D ^ (B & (C ^ D))
g = i
elif i <= 31:
# f = (D & B) | (not32(D) & C)
f = C ^ (D & (B ^ C))
g = (5 * i + 1) % 16
elif i <= 47:
f = B ^ C ^ D
g = (3 * i + 5) % 16
else:
f = C ^ (B | not32(D))
g = (7 * i) % 16
dtemp = D
D = C
C = B
B = sum32(B, leftrot32((A + f + tvals[i] + m[g]) % 2**32, s[i]))
A = dtemp
a0 = sum32(a0, A)
b0 = sum32(b0, B)
c0 = sum32(c0, C)
d0 = sum32(d0, D)

digest = reformatHex(a0) + reformatHex(b0) + reformatHex(c0) + reformatHex(d0)
return digest

def test():
assert md5me("") == "d41d8cd98f00b204e9800998ecf8427e"
assert (
md5me("The quick brown fox jumps over the lazy dog")
== "9e107d9d372bb6826bd81d3542a419d6"
)
print("Success.")

if __name__ == "__main__":
test()
import doctest

doctest.testmod()
``````