Project_Code.ipynb

{
  "nbformat": 4,
  "nbformat_minor": 0,
  "metadata": {
    "colab": {
      "name": "Encryption.ipynb",
      "provenance": [],
      "collapsed_sections": []
    },
    "kernelspec": {
      "name": "python3",
      "display_name": "Python 3"
    },
    "language_info": {
      "name": "python"
    }
  },
  "cells": [
    {
      "cell_type": "markdown",
      "source": [
        "Diffie Hellman"
      ],
      "metadata": {
        "id": "ML349qt08pr4"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "import math\n",
        "\n",
        "# Let A be the sender\n",
        "# Let B be the receiver\n",
        "\n",
        "def key_A_gen(a, p ,g):   # Key generated by the sender A\n",
        "  x = int(pow(g,a,p))\n",
        "  return x\n",
        "\n",
        "def key_B_gen(b, p, g):  # Key generated by the receiver B\n",
        "  y = int(pow(g,b,p))\n",
        "  return y\n",
        "\n",
        "def secret_key_gen_A(a, b, p, g):\n",
        "  y = key_B_gen(b,p,g)           # The key that A will get after key exchange\n",
        "  secret_key = int(pow(y,a,p))   # w.r.t the sender A after key exchange\n",
        "  return secret_key\n",
        "\n",
        "def secret_key_gen_B(a, b, p, g):\n",
        "  x = key_A_gen(a,p,g)           # The key that B will get after key exchange\n",
        "  secret_key = int(pow(x,b,p))   # w.r.t the sender A after key exchange\n",
        "  return secret_key\n",
        "\n",
        "# Both the persons will be agreed upon the public keys p and g\n",
        "# Let p be a prime number\n",
        "# Let g be a primitive root of p\n",
        "p = 13  \n",
        "g = 6\n",
        "\n",
        "# The sender A is allocated a private key a \n",
        "# The receiver B is allocated a private key b\n",
        "a = 4\n",
        "b = 2\n",
        "\n",
        "# Key generated by Sender A\n",
        "key_A = key_A_gen(a, p, g)\n",
        "\n",
        "# Key generated by Receiver B\n",
        "key_B = key_B_gen(b, p, g)\n",
        "\n",
        "# Now the keys generated are exchanged between each other\n",
        "# Therefore, A will be key_B and B will get key_A\n",
        "\n",
        "# Secret key generated by A\n",
        "secret_key_A = secret_key_gen_A(a, b, p, g)\n",
        "\n",
        "# Secret key generated by B\n",
        "secret_key_B = secret_key_gen_B(a, b, p, g)\n",
        "\n",
        "# Testing and outputing the secret_key\n",
        "if(secret_key_A == secret_key_B):\n",
        "  secret_key = secret_key_A\n",
        "else:\n",
        "  secret_key = 0\n",
        "  print(\"Algorithm is wrong\")\n",
        "\n",
        "print(secret_key)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "baGQ0UNv8l-f",
        "outputId": "6c21f29f-88cc-49cc-b85a-26a1c7564450"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "3\n"
          ]
        }
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "Encryption"
      ],
      "metadata": {
        "id": "8g6zmIbspb17"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "import sympy as sym\n",
        "import math\n",
        "import numpy as np6\n",
        "import time\n",
        "from numpy.linalg import norm\n",
        "start = time.time()\n",
        "\n",
        "def func(x, secret_key, ascii):\n",
        "    return secret_key * x * x * x - 2.7 * x - ascii\n",
        "\n",
        "\n",
        "def derivfunc(x):\n",
        "    return 3 * secret_key * x * x - 2.7\n",
        "\n",
        "\n",
        "def bisection(a, b, e, secret_key, ascii):\n",
        "    if (func(a, secret_key, ascii) * func(b,secret_key, ascii) >= 0):\n",
        "        return\n",
        "    c = a\n",
        "    iter=1\n",
        "    while ((b - a) >= e):\n",
        "\n",
        "        # Find middle point\n",
        "        c = (a + b) / 2\n",
        "\n",
        "        # Check if middle point is root\n",
        "        if (func(c, secret_key, ascii) == 0.0):\n",
        "            break\n",
        "        if (func(c, secret_key, ascii) * func(a, secret_key, ascii) < 0):\n",
        "            b = c\n",
        "        else:\n",
        "            a = c\n",
        "        iter+=1\n",
        "    return c, iter\n",
        "    \n",
        "\n",
        "\n",
        "\n",
        "def newton_raphson(x, secret_key, ascii):\n",
        "    h = func(x, secret_key, ascii) / derivfunc(x)\n",
        "    iter = 1\n",
        "    while abs(h) >= 0.0001:\n",
        "        h = func(x, secret_key, ascii) / derivfunc(x)\n",
        "        x = x - h\n",
        "        iter+=1\n",
        "\n",
        "    return x, iter\n",
        "\n",
        "\n",
        "def secant(x1, x2, E, secret_key, ascii):\n",
        "    n = 0\n",
        "    xm = 0\n",
        "    x0 = 0\n",
        "    c = 0\n",
        "    if (func(x1,secret_key,ascii) * func(x2,secret_key,ascii) < 0):\n",
        "        while True:\n",
        "\n",
        "            \n",
        "            x0 = ((x1 * func(x2,secret_key,ascii) - x2 * func(x1,secret_key,ascii)) /\n",
        "                  (func(x2,secret_key,ascii) - func(x1,secret_key,ascii)))\n",
        "\n",
        "\n",
        "            c = func(x1,secret_key,ascii) * func(x0,secret_key,ascii)\n",
        "\n",
        "            \n",
        "            x1 = x2\n",
        "            x2 = x0\n",
        "\n",
        "            \n",
        "            n += 1\n",
        "\n",
        "\n",
        "            if (c == 0):\n",
        "                break\n",
        "            xm = ((x1 * func(x2,secret_key,ascii) - x2 * func(x1,secret_key,ascii)) /\n",
        "                  (func(x2,secret_key,ascii) - func(x1,secret_key,ascii)))\n",
        "\n",
        "            if (abs(xm - x0) < E):\n",
        "                break\n",
        "    return x0,n\n",
        "\n",
        "\n",
        "\n",
        "file = open(\"/content/Group3_Text.txt\", \"r\")\n",
        "\n",
        "characters = []\n",
        "\n",
        "for line in file:\n",
        "    for character in line:\n",
        "        characters.append(character)\n",
        "\n",
        "# print(characters)\n",
        "\n",
        "Ascii = []\n",
        "\n",
        "for i in characters:\n",
        "    Ascii.append(ord(i))\n",
        "\n",
        "# print(Ascii)\n",
        "\n",
        "cipher = []\n",
        "\n",
        "\n",
        "\n",
        "# for i in Ascii:\n",
        "#  x0 = -1\n",
        "#  x1 = 5\n",
        "#  cipher.append(bisection(x0, x1, 0.0001,secret_key, int(i)))\n",
        "\n",
        "# for i in Ascii:\n",
        "#     x0 = -1\n",
        "#     cipher.append(newton_raphson(x0, secret_key, int(i)))\n",
        "\n",
        "for i in Ascii:\n",
        "   x1 = 0\n",
        "   x2 = 5\n",
        "   cipher.append(secant(x1,x2,0.001,secret_key, int(i)))\n",
        "\n",
        "ciptxt=''\n",
        "for i in cipher:\n",
        "\n",
        "    ciptxt+=str(i[0])+'@'\n",
        "\n",
        "fi=open('cipher.txt','w+')\n",
        "fi.write(ciptxt)\n",
        "end = time.time()\n",
        "total_time = end-start\n",
        "print(total_time)"
      ],
      "metadata": {
        "id": "V20ar18YpaUX",
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "outputId": "4f93fa09-128b-4592-c4ff-efaee9f1595d"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "0.0012028217315673828\n"
          ]
        }
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "Decryption"
      ],
      "metadata": {
        "id": "BQCKxzKl7wc1"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "fi=open('cipher.txt','r')\n",
        "\n",
        "def func(x, secret_key):\n",
        "    return secret_key * x * x * x - 2.7 * x\n",
        "\n",
        "msg=[]\n",
        "\n",
        "de=['']\n",
        "c=0\n",
        "\n",
        "for i in fi:\n",
        "    for j in str(i):\n",
        "        if(j=='@'):\n",
        "            c+=1\n",
        "            de.append('')\n",
        "        else:\n",
        "            de[c]+=str(j)\n",
        "\n",
        "de.pop()\n",
        "for i in de:\n",
        "  msg.append(chr(round(func(float(i), secret_key))))\n",
        "\n",
        "pltxt=''\n",
        "for i in msg:\n",
        "    pltxt+=i\n",
        "\n",
        "fid=open('decrypted.txt','w+')\n",
        "fid.write(pltxt)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "VYSz7neF1MEx",
        "outputId": "9a0df182-eeea-4a07-8518-f54949b1646a"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "execute_result",
          "data": {
            "text/plain": [
              "9"
            ]
          },
          "metadata": {},
          "execution_count": 15
        }
      ]
    }
  ]
}