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remove mention of old ctypes version
author Benjamin Peterson <benjamin@python.org>
date Sat, 23 May 2009 20:59:09 +0000
parents 9815da43a1ce
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2 :mod:`crypt` --- Function to check Unix passwords
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3 =================================================
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5 .. module:: crypt
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6 :platform: Unix
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7 :synopsis: The crypt() function used to check Unix passwords.
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8 .. moduleauthor:: Steven D. Majewski <sdm7g@virginia.edu>
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9 .. sectionauthor:: Steven D. Majewski <sdm7g@virginia.edu>
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10 .. sectionauthor:: Peter Funk <pf@artcom-gmbh.de>
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13 .. index::
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14 single: crypt(3)
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15 pair: cipher; DES
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17 This module implements an interface to the :manpage:`crypt(3)` routine, which is
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18 a one-way hash function based upon a modified DES algorithm; see the Unix man
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19 page for further details. Possible uses include allowing Python scripts to
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20 accept typed passwords from the user, or attempting to crack Unix passwords with
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21 a dictionary.
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23 .. index:: single: crypt(3)
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25 Notice that the behavior of this module depends on the actual implementation of
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26 the :manpage:`crypt(3)` routine in the running system. Therefore, any
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27 extensions available on the current implementation will also be available on
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28 this module.
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31 .. function:: crypt(word, salt)
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33 *word* will usually be a user's password as typed at a prompt or in a graphical
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34 interface. *salt* is usually a random two-character string which will be used
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35 to perturb the DES algorithm in one of 4096 ways. The characters in *salt* must
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36 be in the set ``[./a-zA-Z0-9]``. Returns the hashed password as a string, which
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37 will be composed of characters from the same alphabet as the salt (the first two
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38 characters represent the salt itself).
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40 .. index:: single: crypt(3)
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42 Since a few :manpage:`crypt(3)` extensions allow different values, with
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43 different sizes in the *salt*, it is recommended to use the full crypted
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44 password as salt when checking for a password.
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45
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46 A simple example illustrating typical use::
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47
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48 import crypt, getpass, pwd
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50 def login():
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51 username = raw_input('Python login:')
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52 cryptedpasswd = pwd.getpwnam(username)[1]
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53 if cryptedpasswd:
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54 if cryptedpasswd == 'x' or cryptedpasswd == '*':
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55 raise "Sorry, currently no support for shadow passwords"
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56 cleartext = getpass.getpass()
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57 return crypt.crypt(cleartext, cryptedpasswd) == cryptedpasswd
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58 else:
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59 return 1
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