"Los hash son algoritmos que consiguen crear a partir de una entrada de datos, una salida alfanumérica de longitud normalmente fija que representa un resumen de toda la información que se le ha dado. Más sobre los hash".

# Algoritmo de Resumen de Mensaje 5 (MD5)

from __future__ import print_function
import math

def rearrange(bitString32):
 if len(bitString32) != 32:
  raise ValueError("Necesita una longitud de 32")
 newString = ""
 for i in [3,2,1,0]:
  newString += bitString32[8*i:8*i+8]
 return newString

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

def pad(bitString):
 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):
 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):
 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):
 bs =''
 for i in testString:
  bs += format(ord(i),'08b')
 bs = pad(bs)

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

 a0 = 0x67452301
 b0 = 0xefcdab89
 c0 = 0x98badcfe
 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():
    mensaje = "mypassword"
    hash_md5 = md5me(mensaje)
    print('"%s" = %s' % (mensaje, hash_md5))

if __name__ == "__main__":
 test()

"mypassword" = 34819d7beeabb9260a5c854bc85b3e44