code.delx.au - monosys/blob - scripts/psi-password.py

   1 #!/usr/bin/env python
   2 # Copyright 2007 James Bunton <jamesbunton@fastmail.fm>
   3 # Licensed for distribution under the GPL version 2, check COPYING for details
   4 # Decodes a password taken from a Psi config.xml file
   5
   6
   7 import sys
   8
   9 def decodePassword(passwd, key):
  10         if not key:
  11                 return passwd
  12
  13         result = ""
  14         n1 = n2 = 0
  15         while n1 < len(passwd):
  16                 x = 0
  17                 if n1 + 4 > len(passwd):
  18                         break
  19                 x += int(passwd[n1+0], 16) * 4096
  20                 x += int(passwd[n1+1], 16) * 256
  21                 x += int(passwd[n1+2], 16) * 16
  22                 x += int(passwd[n1+3], 16) * 1
  23                 result += chr(x ^ ord(key[n2]))
  24                 n1 += 4
  25                 n2 += 1
  26                 if n2 >= len(key):
  27                         n2 = 0
  28
  29         return result
  30
  31 if __name__ == "__main__":
  32         try:
  33                 passwd = sys.argv[1]
  34                 key = sys.argv[2]
  35         except:
  36                 print >> sys.stderr, "Usage: %s passwd jid" % sys.argv[0]
  37                 sys.exit(1)
  38         print decodePassword(passwd, key)
  39