convert String to MD5

问题:

Ok I am trying to write a basic converter of a string to md5 hash code but when I run my program I keep getting an error that say's:

Traceback (most recent call last):   File "C:\Users\Shane\Documents\Amer CISC\lab4.py", line 30, in <module>     assertEqual (computeMD5hash("The quick brown fox jumps over the lazy dog"),("9e107d9d372bb6826bd81d3542a419d6"))   File "C:\Users\Shane\Documents\Amer CISC\lab4.py", line 27, in computeMD5hash     m.update(string) TypeError: Unicode-objects must be encoded before hashing 

My code looks like this:

def computeMD5hash(string):     import hashlib     from hashlib import md5     m = hashlib.md5()     m.update((string))     md5string=m.digest()     return md5string 

回答1:

As the error suggests, your string must be unicode and you have to encode it. Looking at the call you make (from your stack trace):

computeMD5hash("The quick brown fox jumps over the lazy dog") 

it looks like you must be running Python 3 where strings are unicode objects. To encode to a byte representation which can then be processed by the hashlib, change this

m.update((string)) 

to this (if utf-8 is an appropriate encoding for you to use - it depends how you will be using this):

m.update(string.encode('utf-8')) 

If this is all news to you, you should probably read the excellent Python 3 Unicode HOWTO.

---

Also, while I'm here, your code has some other issues

• some unecessary bits - no need for the from hashlib import line or the temporary md5string.
• it's bad form to import modules from within a function, so import hashlib should be moved to module scope.
• the function is returning the digest() which is raw binary, and from your stack trace it looks like you're expecting the hexdigest() instead which is the same thing represented as a hexadecimal string.

To fix and tidy it all up, try this:

import hashlib  def computeMD5hash(my_string):     m = hashlib.md5()     m.update(my_string.encode('utf-8'))     return m.hexdigest() 

回答2:

Rather than trying to hash the string, you should hash an encoded byte sequence. Instead of

>>> import hashlib >>> hashlib.md5("fred") Traceback (most recent call last):   File "<stdin>", line 1, in <module> TypeError: Unicode-objects must be encoded before hashing 

you should encode it, e.g.:

>>> "fred".encode("utf") b'fred' >>> hashlib.md5("fred".encode("utf")).hexdigest() '570a90bfbf8c7eab5dc5d4e26832d5b1' 

In Python 2 you could get away without doing this, and it led to no end of unnoticed bugs. Fortunately Python 3 has much saner unicode support, and distinguishes between bytes and strings.

回答3:

Seems you have to encode the string before hashing:

http://www.dreamincode.net/forums/topic/246026-generating-string-hash-issue/

回答4:

!/usr/bin/env python

coding=utf-8

import sys, os, stat import pygtk, gtk import zbarpygtk import pycurl from time import strftime, localtime import pango

class qrdat:

def __init__(self):      """ VARIABLES DE CONFIGURACION """     # Prefijo para el nombre de los archivos de registros      prefijo = 'Registro'      # Lugar de almacenamiento de archivos de registros     # Por defecto se guarda en la carpeta personal del usuario     directorio = os.getenv('HOME')      # Descomentar la siguiente linea y digitar la ruta de la carpeta     # donde se guardaran los archivos      #directorio = '/home/olpc/Escritorio'       # Modo de reproduccion de sonido:     # 1 : sonido enviado directamente a la tarjeta de sonido     # 2 : sonido de alerta del sistema      self.beep_mode = 1      # No modificar abajo     self.open_file = None     self.video_device = '/dev/video0'     self.fecha = strftime("%Y-%m-%d",localtime())     self.filename = directorio+'/'+prefijo+'-'+self.fecha+'.csv'      if len(sys.argv) > 1:         self.video_device = sys.argv[1]  def decoded(self, zbar, data):     """funcion invocada cuando un codigo es decodificado por el     control zbar.      """     datos = data.split(':')     qrdata = datos[1]      # guardar datos     self.save(qrdata)              # sonido de recepcion     self.beep(self.beep_mode)      # mostrar datos     buf = self.results.props.buffer     end = buf.get_end_iter()     buf.insert(end, self.hora()+' - '+qrdata+"\n")     self.results.scroll_to_iter(end, 0)  def show(self):     """Funcion que crea muestra la ventana principal """      # threads *must* be properly initialized to use zbarpygtk     gtk.gdk.threads_init()     gtk.gdk.threads_enter()      window = gtk.Window()     window.set_title("Control de Asistencia QR")     window.set_border_width(8)     window.connect("destroy", gtk.main_quit)      # zbar     self.zbar = zbarpygtk.Gtk()     self.zbar.connect("decoded-text", self.decoded)      self.video_device = '/dev/video0'      self.zbar.connect("notify::video-enabled", self.video_enabled)     self.zbar.connect("notify::video-opened", self.video_opened)      self.zbar.set_video_device(self.video_device)      # combine combo box and buttons horizontally     hbox = gtk.HBox(spacing=8)      # text box for holding results     self.results = gtk.TextView()     self.results.set_size_request(320, 128)     self.results.props.editable = self.results.props.cursor_visible = False     self.results.modify_font(pango.FontDescription("monospace 12"))     self.results.set_left_margin(4)      # combine inputs, scanner, and results vertically     vbox = gtk.VBox(spacing=8)     vbox.pack_start(hbox, expand=False)     vbox.pack_start(self.zbar)     vbox.pack_start(self.results, expand=False)      window.add(vbox)     window.set_geometry_hints(self.zbar, min_width=320, min_height=240)     window.show_all()   def run(self):     """Funcion que inicia el funcionamiento de la ventana"""     gtk.main()     gtk.gdk.threads_leave()  def save(self,data):     """ Funcion que guarda el archivo de registro """     f = open(self.filename,'a')     f.write(self.fecha+','+self.hora()+','+data+'\n')     f.close()  def hora(self):     """ Funcion que obtiene la hora local """     return strftime("%H:%M:%S",localtime())  def beep(self, beep_mode):      if os.access('/dev/audio', os.W_OK ) and beep_mode == 1:         """ Genera un sonido enviado a la tarjeta de sonido"""         frequency = 100         amplitude = 200         duration = 2         sample = 8000         half_period = int(sample/frequency/2)         beep = chr(amplitude)*half_period+chr(0)*half_period         beep *= int(duration*frequency)         audio = file('/dev/audio', 'wb')         audio.write(beep)         audio.close()      else:         """ Reproduce sonido del propio sistema """         f=open('/dev/tty','w')         f.write(chr(7))         f.close()   def video_enabled(self, zbar, param):     """callback invoked when the zbar widget enables or disables     video streaming.  updates the status button state to reflect the     current video state     """     enabled = zbar.get_video_enabled()   def video_opened(self, zbar, param):     """callback invoked when the zbar widget opens or closes a video     device.  also called when a device is closed due to error.     updates the status button state to reflect the current video state     """     opened = zbar.get_video_opened()  def video_changed(self, widget):     """callback invoked when a new video device is selected from the     drop-down list.  sets the new device for the zbar widget,     which will eventually cause it to be opened and enabled     """     dev = self.video_list.get_active_text()     if dev[0] == '<':         dev = ''     self.zbar.set_video_device(dev) 

if name == "main":

qr = qrdat() qr.show() qr.run() 

文章来源: convert String to MD5