a2_1.ipynb

a2_2.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 484,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "000100010000FFFF\n",
      "FFFF0000000000010001000100010001\n"
     ]
    }
   ],
   "source": [
    "# input='7fa9 1c37 ffb3 df05'.replace(' ','')\n",
    "# key='5a14 fb3e 021c 79e0 6081 46a0 117b ff03'.replace(' ','')\n",
    "# test input and key from fall 2014\n",
    "# The input  data block is: 0001 0001 0000 FFFF        &\n",
    "# The encryption key is:   FFFF 0000 0000 0001 0001 0001 0001 0001\n",
    "# Answer: 0002 FFFD FFFD  0003\n",
    "input='0001 0001 0000 FFFF'.replace(' ','')\n",
    "key='FFFF 0000 0000 0001 0001 0001 0001 0001'.replace(' ','')\n",
    "\n",
    "\n",
    "print input\n",
    "print key\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 485,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['FFFF', '0000', '0000', '0001', '0001', '0001']\n",
      "16\n",
      "['1111111111111111', '0000000000000000', '0000000000000000', '0000000000000001', '0000000000000001', '0000000000000001']\n"
     ]
    }
   ],
   "source": [
    "# # key\n",
    "# tokenize the key into 6 groups,each 4 hex digits\n",
    "z=[]\n",
    "for i in range(6):\n",
    "    z.append(key[4*i:4*i+4])\n",
    "print z\n",
    "# convert the 4 hex digits to 16 bit binary string\n",
    "for i in range(6):\n",
    "    z[i]=\"{0:016b}\".format(int(z[i], 16))\n",
    "#     z[i]=bin(int(z[i], 16))\n",
    "print len(z[0])\n",
    "print z\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 486,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['0001', '0001', '0000', 'FFFF']\n"
     ]
    }
   ],
   "source": [
    "# plain text\n",
    "x=[]\n",
    "x.append(input[0:4])\n",
    "x.append(input[4:8])\n",
    "x.append(input[8:12])\n",
    "x.append(input[12:16])\n",
    "print x\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 487,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['0000000000000001', '0000000000000001', '0000000000000000', '1111111111111111']\n",
      "['1111111111111111', '0000000000000000', '0000000000000000', '0000000000000001', '0000000000000001', '0000000000000001']\n"
     ]
    }
   ],
   "source": [
    "# hex to binary\n",
    "\n",
    "for i in range(len(x)):\n",
    "#     x[i]=\"{0:016b}\".format(int(x[i], 16))\n",
    "# hex to int, \n",
    "# then int to binary\n",
    "#     bstr=\"{0:016b}\".format(int(x[i], 16))\n",
    "#     x[i]=bin(int(bstr, 2))\n",
    "    x[i]=\"{0:016b}\".format(int(x[i], 16))\n",
    "print x\n",
    "print z\n",
    "\n",
    "# print \"{0:0416b}\".format(int(x[0], 2))+\"{0:016b}\".format(int(x[1], 2))\n",
    "\n",
    "# xa= \"{0:016b}\".format(int('7fa9', 16))\n",
    "# print xa\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 488,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1111111111111111\n",
      "0000000000000001\n",
      "\n",
      "\n",
      "65535 1 0 65535 65535 65534 65535 65533 65533 65532 2 65533 65533 3\n",
      "0x2 0xfffd 0xfffd 0x3\n",
      "16\n"
     ]
    }
   ],
   "source": [
    "print z[0]\n",
    "print x[0]\n",
    "print \n",
    "r1=( int(x[0],2)*int(z[0],2) )%(2**16+1)\n",
    "r2=( int(x[1],2)+int(z[1],2) )%(2**16)\n",
    "r3=( int(x[2],2)+int(z[2],2) )%(2**16)\n",
    "r4=( int(x[3],2)*int(z[3],2) )%(2**16+1)\n",
    "r5=r1^r3\n",
    "r6=r2^r4\n",
    "r7=(r5* int(z[4],2))%(2**16+1)\n",
    "r8= (r6+r7)%(2**16)\n",
    "r9=r8*int(z[5],2)%(2**16+1)\n",
    "r10= (r7+r9)%(2**16)\n",
    "r11= r1^r9\n",
    "r12= r3^r9\n",
    "r13= r2^r10\n",
    "r14= r4^r10\n",
    "print \n",
    "# print r1,r2,r3,r4,r5,r6,r7,r8,r9,r10,r11,r12,r13,r14\n",
    "# Answer for Fall2014: 0002 FFFD FFFD  0003\n",
    "#below is the answer for the given input\n",
    "# choose the input to be the one for FALL2014,I have the same answer\n",
    "# So I believe my answer is correct for FALL2015 input\n",
    "print hex(r11),hex(r12),hex(r13),hex(r14)\n",
    "\n",
    "print len('1111111111111101')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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a2_3.ipynb