source: bin/bletchley-analyze @ 17

#!/usr/bin/env python

# Requires Python 2.7+

'''
Simple script to leverage some of the blobtools features

Copyright (C) 2011-2012 Virtual Security Research, LLC
Author: Timothy D. Morgan

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License, version 3,
 as published by the Free Software Foundation.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
'''


import sys
import argparse
import binascii
from bletchley import blobtools,buffertools


parser = argparse.ArgumentParser(description='Analyzes samples of encrypted data in an attempt to decode samples to binary and identify patterns useful in cryptanalysis.')
parser.add_argument('input_file', nargs='?', default=None,
                    help='File containing encrypted blobs to analyze, one per line. Omit to read from stdin.')
parser.add_argument('-e', dest='encoding_chain', type=str, default=None,
                    help='Comma-separated sequence of formats used to encode the tokens, beginning with the last one applied. (default: auto-detect)')
parser.add_argument('-b', dest='block_size', type=int, default=8,
                    help='The block size displayed and used in highlighting (default: 8)')
parser.add_argument('-p', dest='output_lines', type=int, default=10,
                    help='Number of lines of input to display in decoded form.')
parser.add_argument('-c', action='store_const', const=True, default=False,
                    help='Use color output for decoded highlights.')
parser.add_argument('-c256', action='store_const', const=True, default=False,
                    help='Use 256 color output for decoded highlights.')
options = parser.parse_args()

input_file = sys.stdin
if options.input_file is not None:
    input_file = file(options.input_file, 'rb')


blobs = input_file.read().rstrip('\n').replace('\r', '').split('\n')
#print(repr(blobs))

def terminalHighlightedString(code, s):
    global options
    if code == None:
        return s

    if options.c256:
        fg = code%216+16
        bg = (code^0xffffffff)%216+16
        return "\x1b[0;38;05;%d;48;05;%dm%s\x1b[0m" % (fg,bg,s)
    elif options.c:
        fg = code%6+31
        bg = (code^0xffffffff)%6+41
        return "\x1b[0;%d;%dm%s\x1b[0m" % (fg,bg,s)
    else:
        return "\x1b[7m%s\x1b[0m" % s


def printColoredHexDump(blobs, group_size=8):    
    line_size = 64
    group_size *= 2 # two hex digits per byte
    print(group_size)
    hex_blobs = map(binascii.b2a_hex, blobs)
    color_map = buffertools.blockWiseColorMap(group_size, hex_blobs)

    for k in range(0,len(hex_blobs)):
        hex = hex_blobs[k]
        
        for i in range(0,len(hex),line_size):
            line = '%.4X: ' % i

            if len(hex[i:]) < line_size:
                hex += (line_size-len(hex[i:]))*' '

            for j in range(0,line_size,group_size):
                group = hex[i+j:i+j+group_size]
                line += terminalHighlightedString(color_map.get(group, None), group) + ' ' 
       
            line += '| '
            line += repr(blobs[k][i/2:(i+line_size)/2])
        
            print(line)
        print('')



def analyze(blobs):
    lengths = blobtools.getLengths(blobs)
    print('Unique Lengths: ' + ','.join(map(str, lengths)))

    max_block_size = blobtools.maxBlockSize(lengths)
    print('Maximum Possible Block Size: %d' % max_block_size)

    block_sizes = blobtools.checkCommonBlocksizes(lengths)
    print('Matching Common Block Sizes: %s' % ','.join(map(str, block_sizes)))

    encodings = blobtools.encodingIntersection(blobs)
    print('Possible Encodings: ' + ','.join(encodings))

    encoding = blobtools.bestEncoding(encodings)
    print('Best Encoding: %s' % encoding)

    return encoding,block_sizes

specified_encodings = []
if options.encoding_chain != None:
    specified_encodings = options.encoding_chain.split(',')

encoding_chain = []
encoding = 'dummy'
while encoding != None:
    print('='*80)
    print('Beginning analysis after decoding by chain: %s' % ','.join(encoding_chain))
    encoding,block_sizes = analyze(blobs)
    if len(specified_encodings) > 0:
        encoding = specified_encodings.pop(0)


    blobs_to_print = blobs[:options.output_lines]
    print('First %d Values:' % len(blobs_to_print))

    printColoredHexDump(blobs_to_print, options.block_size)

    if encoding != None:
        encoding_chain.append(encoding)
        blobs = blobtools.decodeAll(encoding, blobs)