gnu readline – python

September 25, 2008 Leave a comment

This is the very start of our cryptanal program frontend

#!/usr/bin/env python

import readline

"""The shell class is the front end for cryptanal"""

class shell:
  def __init__(self, filename=None):
    print"""
WWW         WW eEeEeEeE LL        CCCCC    OOOO    MMMM    MMMM  eEeEeEeE
 WW         W  EE       LL       Cc      OOO  OOO  MM MM  M  MM  EE
  WW       WW  EeEeE    LL      CC       OO    OO  MM  MMM   MM  EeEeE
  WWw WW  WW   EE       LL       Cc      OOO  OOO  MM        MM  EE
   WWW  WWW    eEeEeEeE LlLlLlL   CCCCC    OOOO    MM        MM  eEeEeEeE

                             TO CRYPTO-SHELL
  (Useful for deciphering what little Susie is writing to little Billy)
"""

    self.filename = filename
    self.crypto = None
    #if self.filename != None:
      #self.crypto = freqcount.subCryptAnal(self.filename)

    #setup the tab completion information here
    self.commands = ["help", "printfreq"]
    readline.set_completer(self.completer)
    readline.parse_and_bind("tab: complete")

  #completer funtion for tab complete
  def completer(self, word, index):
    matches =
    try:
      return matches[index] + " "
    except IndexError:
      pass

  #this is the main event loop
  def mainloop(self):
    while 1:
      command=raw_input('> ').lstrip()
      if command.lower().startswith('help'):
        self.help(command[4:].lstrip())
      else:
        print "Error: command not recognized"

  def help(self, args):
    print "HELP"

if __name__ == '__main__':
  thisshell = shell()
  thisshell.mainloop()

Filed under Security Tools Tagged with

Golay G24

September 8, 2008 Leave a comment

This is a dirty implemenation of Golay correcting code using python.

This is a solution to 18.13 problem 1 from Trappe and Washington’s Crytography book. To run this, you need bash, python, and the numpy libraries. To run, run golay.sh.  The algorithm is located in golay.py

golay.py

#!/usr/bin/env python
 
from numpy import *
import sys
 
geng24 = array([[1,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,1,1,1,0,0,0,1,0],
                [0,1,0,0,0,0,0,0,0,0,0,0,1,0,1,1,0,1,1,1,0,0,0,1],
                [0,0,1,0,0,0,0,0,0,0,0,0,1,1,0,1,1,0,1,1,1,0,0,0],
                [0,0,0,1,0,0,0,0,0,0,0,0,1,0,1,0,1,1,0,1,1,1,0,0],
                [0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,1,0,1,1,0,1,1,1,0],
                [0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,1,0,1,1,0,1,1,1],
                [0,0,0,0,0,0,1,0,0,0,0,0,1,1,0,0,0,1,0,1,1,0,1,1],
                [0,0,0,0,0,0,0,1,0,0,0,0,1,1,1,0,0,0,1,0,1,1,0,1],
                [0,0,0,0,0,0,0,0,1,0,0,0,1,1,1,1,0,0,0,1,0,1,1,0],
                [0,0,0,0,0,0,0,0,0,1,0,0,1,0,1,1,1,0,0,0,1,0,1,1],
                [0,0,0,0,0,0,0,0,0,0,1,0,1,1,0,1,1,1,0,0,0,1,0,1],
                [0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,1,1,1,1,1,1,1]])
 
B = array([[1,1,1,0,1,1,1,0,0,0,1,0],
           [1,0,1,1,0,1,1,1,0,0,0,1],
           [1,1,0,1,1,0,1,1,1,0,0,0],
           [1,0,1,0,1,1,0,1,1,1,0,0],
           [1,0,0,1,0,1,1,0,1,1,1,0],
           [1,0,0,0,1,0,1,1,0,1,1,1],
           [1,1,0,0,0,1,0,1,1,0,1,1],
           [1,1,1,0,0,0,1,0,1,1,0,1],
           [1,1,1,1,0,0,0,1,0,1,1,0],
           [1,0,1,1,1,0,0,0,1,0,1,1],
           [1,1,0,1,1,1,0,0,0,1,0,1],
           [0,1,1,1,1,1,1,1,1,1,1,1]])
 
errorvector = array([0,0,0,0,0,0,0,0,0,0,0,0])
 
def weight(obj):
  wt = 0
  for i in obj:
    wt += i
  return wt
 
geng24_transpose = geng24.transpose()
 
#r = array([1,1,0,1,0,0,0,0,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0])
#r = array([0,1,0,0,0,0,1,1,0,1,0,1,1,0,1,1,0,1,0,0,0,0,1,1])
#r = array([0,0,1,0,1,0,1,0,1,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0])
#r = array([1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1])
 
r = []
for i in sys.argv[1].split(','):
  r.append(int(i))
r = array(r)
 
s = (dot(r,geng24_transpose) % 2 )
 
sdotb = (dot(s,B) % 2 )
 
#e = array([0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0])
e = zeros( (1,24), dtype=int8)
e = e.flat
 
if weight(s) <= 3:
  print "ERROR CORRECTION 3"
  e = array([s, array([0,0,0,0,0,0,0,0,0,0,0,0])])
  e.shape = (1,24)
  e = e.flat
 
if weight(sdotb) <= 3:
  print "ERROR CORRECTION 4"
  e_new = array([array([0,0,0,0,0,0,0,0,0,0,0,0]), sdotb])
  e_new.shape = (1,24)
  e = (e + e_new) % 2
  e = e.flat
 
for j in range(12,24):
  if weight((geng24[:,j] + s)%2) < 2:
    print "ERROR CORRECTION 5"
    e[j] = 1
    e_new = array([(geng24[:,j]+s)%2, array([0,0,0,0,0,0,0,0,0,0,0,0])])
    e_new.shape = (1,24)
    e = (e + e_new) % 2
    e = e.flat
 
for j in range(0,12):
  if weight((sdotb + B[j,:])%2) <= 2:
    print "ERROR CORRECTION 6"
    e[j] = 1
    e_new = array([array([0,0,0,0,0,0,0,0,0,0,0,0]),((sdotb + B[j,:])%2)])
    e_new.shape = (1, 24)
    e = (e + e_new) % 2
    e = e.flat
 
print "\ne =  [",
for i in e:
  print i,
print "]\n"
 
c = ((e + r)%2)
m = array(c[:12])
 
print "r = ", r
print "c = ", c
print "m = ", m

Here is golay.sh

#!/bin/bash
 
echo "Running with Example Problem"
echo "==========================="
./golay.py 1,1,0,1,0,0,0,0,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0
 
echo "
Running with Problem1"
echo "==========================="
./golay.py 0,1,0,0,0,0,1,1,0,1,0,1,1,0,1,1,0,1,0,0,0,0,1,1
 
echo "
Running with Problem2"
echo "==========================="
./golay.py 0,0,1,0,1,0,1,0,1,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0
 
echo "
Running with Problem3"
echo "==========================="
./golay.py 1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1

Filed under Crypto Tagged with , ,

isbn-10 validity identifier

September 1, 2008 Leave a comment

Here’s a program that does the isbn error checking.

#!/usr/bin/env python

#this program checks if isbn-10 numbers are valid

import sys

def usage():
  "You're using it wrong!"

try:
  isbn = sys.argv[1].replace('-','')
except:
  usage()

isbnNum = isbn[0:9]
checksumPassed = int(isbn[9:])

sum = 0
index = 10
for i in isbnNum:
  sum += int(i)* index
  index -= 1
print "sum is ", sum
checksum = 11 - (sum % 11)

print 11 - checksum
if checksum == checksumPassed:
  print "isbn checksum is fine"
else:
  print "isbn checksum error"

Filed under Misc Tagged with

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