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Adding bit diff finder - wip tool to generate dict that can be used for computing crc for novel messages
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2 files changed

+318
-19
lines changed

2 files changed

+318
-19
lines changed

‎analysis/bit_diff_finder.ipynb

+313
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@@ -0,0 +1,313 @@
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{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": 48,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"import pandas as pd\n",
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"%matplotlib inline\n",
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"import matplotlib\n",
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"import numpy as np\n",
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"import matplotlib.pyplot as plt\n",
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"import dateutil\n",
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"import analysis\n",
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"import itertools\n",
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"\n",
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"packets = analysis.parse_packet_file('data/all.txt')\n",
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"packets += analysis.parse_packet_file('data/temp_basals.txt')\n",
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"\n",
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"\n",
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"# Select valid packets of a particular length\n",
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"packets = filter(lambda x: x.is_valid() and x.body_len == 10, packets)\n",
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"\n",
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"# Uncomment if you want to work with less data (faster while developing)\n",
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"packets = packets[0:100]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 49,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"def diff(m1,m2):\n",
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" xored_bytes = [ord(a) ^ ord(b) for a,b in zip(m1,m2)]\n",
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" return xored_bytes\n",
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"\n",
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"def bits(data):\n",
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" return np.unpackbits(np.frombuffer(data, dtype=np.uint8))\n",
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"\n",
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"def join_ints(ints):\n",
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" return ':'.join(str(x) for x in ints)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 61,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class DiffMessage(object):\n",
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"\n",
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" # data is passed in like this: ((m1,c1),(m2,c2))\n",
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" def __init__(self, combination):\n",
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" self.m1 = combination[0][0]\n",
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" self.c1 = combination[0][1]\n",
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" self.m2 = combination[1][0]\n",
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" self.c2 = combination[1][1]\n",
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" \n",
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" # diffs\n",
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" self.dm = diff(self.m1, self.m2)\n",
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" self.dc = diff(self.c1, self.c2)\n",
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" \n",
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" # diff stats\n",
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" diff_bits = np.unpackbits(np.array(self.dm, dtype=np.uint8))\n",
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" self.diff_bits_count = diff_bits.sum()\n",
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" self.diff_bits_key = join_ints(np.where(diff_bits)[0].tolist())\n",
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" \n",
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" self.confirmations = 0\n",
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" self.conflicts = 0\n",
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" \n",
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" def update_observation(self, other):\n",
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" if other.dc == self.dc:\n",
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" self.confirmations += 1\n",
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" else:\n",
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" self.conflicts += 1\n",
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" \n",
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" def __str__(self):\n",
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" return \"%s: msg=%s, crc=%s\" % (self.diff_bits_key, self.dm, self.dc)\n",
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" \n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"2016-06-26T20:33:28.412197 ID1:1f01482a PTYPE:PDM SEQ:13 ID2:1f01482a B9:10 BLEN:3 MTYPE:0e01 BODY:00802c CRC:88\n"
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]
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}
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],
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"source": [
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"print packets[0]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 5,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"1f01482aad1f01482a10030e0100802c88\n"
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]
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}
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],
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"source": [
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"print packets[0].tx_data().encode('hex')"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 67,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"# This expresses our theory about which bits are CRC, and which bits\n",
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"# are included in CRC calculation. Takes a full message and splits it\n",
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"# into message,crc\n",
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"def parts(data):\n",
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" msg = data[5:-3] # Everything except ID1, byte 4 (sequence & flags), packet crc, and 16bit chksum\n",
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" chksum = data[-3:-1]\n",
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" return (msg, chksum)\n",
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"\n",
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"data = [parts(p.tx_data()) for p in packets]\n",
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"#diffs = [DiffMessage(c) for c in itertools.combinations(data, 2)]\n",
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"\n",
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"cracked_bits_dict = {}\n",
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"for c in itertools.combinations(data, 2):\n",
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" d = DiffMessage(c)\n",
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" if d.diff_bits_count == 0:\n",
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" continue\n",
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" if d.diff_bits_key in cracked_bits_dict:\n",
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" cracked_bits_dict[d.diff_bits_key].update_observation(d)\n",
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" else:\n",
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" cracked_bits_dict[d.diff_bits_key] = d\n",
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" \n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 68,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"['36', '35', '34']"
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]
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},
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"execution_count": 68,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"[key for key in cracked_bits_dict.keys() if len(key.split(':')) == 1]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 76,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"36:80:115: msg=[0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 128, 0, 0, 0, 16, 0], crc=[129, 61]\n"
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]
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}
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],
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"source": [
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"print cracked_bits_dict['36:80:115']"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 73,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"['35:36',\n",
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" '35:80',\n",
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" '78:114',\n",
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" '80:116',\n",
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" '80:115',\n",
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" '34:35',\n",
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" '34:36',\n",
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" '35:37',\n",
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" '34:117',\n",
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" '34:116',\n",
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" '36:116',\n",
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" '35:116',\n",
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" '35:117',\n",
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" '36:37']"
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]
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},
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"execution_count": 73,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"[key for key in cracked_bits_dict.keys() if len(key.split(':')) == 2]"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 56,
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"metadata": {
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"collapsed": false,
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"scrolled": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"['36:78:114',\n",
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" '34:37:117',\n",
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" '36:80:116',\n",
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" '36:80:115',\n",
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" '79:115:117',\n",
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" '79:115:116',\n",
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" '35:36:37',\n",
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" '35:115:116',\n",
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" '79:80:114',\n",
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" '34:36:117',\n",
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" '34:36:116',\n",
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" '34:35:80',\n",
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" '36:37:117',\n",
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" '35:37:117',\n",
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" '35:36:80',\n",
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" '34:35:117',\n",
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" '36:79:80',\n",
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" '34:116:117',\n",
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" '79:114:116',\n",
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" '79:114:117',\n",
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" '79:114:115',\n",
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" '34:35:36',\n",
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" '34:36:80',\n",
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" '34:80:115',\n",
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" '34:80:116',\n",
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" '34:80:117',\n",
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" '35:36:116',\n",
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" '35:79:115',\n",
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" '36:116:117',\n",
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" '35:116:117',\n",
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" '36:79:115',\n",
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" '35:80:116',\n",
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" '35:36:117',\n",
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" '80:115:117']"
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]
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},
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"execution_count": 56,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"[key for key in cracked_bits_dict.keys() if len(key.split(':')) == 3]"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 2",
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"language": "python",
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"name": "python2"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 2
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython2",
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"version": "2.7.11"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}

‎analysis/crcplay.ipynb

+5-19
Original file line numberDiff line numberDiff line change
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"import numpy as np\n",
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"import matplotlib.pyplot as plt\n",
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"\n",
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"\n",
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"# Flip a bit in a messsage\n",
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"def flip_bit(msg, idx):\n",
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" bit_offset = idx % 8\n",
@@ -42,18 +41,7 @@
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"'000000000c00000000000000000000000341'"
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]
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},
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"execution_count": 2,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"outputs": [],
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"source": [
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"# 1f014829080a1d1802ad2800002bdfff83c5 xor \n",
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"# 1f014829100a1d1802ad2800002bdfff014b = \n",
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"# 000000000c00000000000000000000000341\n",
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"\n",
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"# C2 = 0341\n",
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"# B1 xor B2 = 000000000c0000000000000000000000 0341\n",
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"diff1 = xor_strings(\"1f02d5af180a1d1801d9180000102fff020a\".decode('hex'), \"1f02d5af140a1d1801d9180000102fff014b\".decode('hex'))\n",
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"diff1.encode('hex')"
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"# B1 xor B2 = 000000000c0000000000000000000000 0341\n"
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]
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},
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{
@@ -82,7 +68,7 @@
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},
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{
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"cell_type": "code",
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"execution_count": 51,
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"execution_count": 3,
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"metadata": {
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"collapsed": false
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},
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},
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{
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"cell_type": "code",
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"execution_count": 56,
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"execution_count": 4,
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"metadata": {
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"collapsed": true
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},
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},
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{
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"cell_type": "code",
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"execution_count": 62,
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"execution_count": 5,
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"metadata": {
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"collapsed": false
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},

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