Security-App/index.html at main · khalidkaram22/Security-App · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>playfair Cipher</title>
  <link rel="icon" type="image/svg+xml" href="favicon.svg" />

  <!-- Tailwind CSS -->
  <link href="https://cdn.jsdelivr.net/npm/tailwindcss@2.2.19/dist/tailwind.min.css" rel="stylesheet">

  <style>
    body {
      font-family: Arial, sans-serif;
      background-color: #f3f4f6;
    }
  </style>
</head>
<body class="min-h-screen flex flex-col">
  <!-- Navbar -->
  <nav class="bg-gray-800 p-4">
    <div class="max-w-7xl mx-auto flex justify-around">
      <a href="trasposition.html" class="text-white text-lg hover:text-blue-400">Transposition </a>
      <a href="rsaImplementation.html" class="text-white text-lg hover:text-blue-400">RSA</a>
      <a href="polyalphabetic.html" class="text-white text-lg hover:text-blue-400">polyalphabetic</a>
      <a href="index.html" class="text-white text-lg hover:text-blue-400">playfair</a>
    </div>
  </nav>

  <!-- Main Content -->
  <div class="bg-white p-8 rounded-lg shadow-lg w-full max-w-xl mx-auto mt-6">
    <h1 class="text-2xl font-bold mb-6 text-center">playfair Cipher</h1>

    <div class="mb-4">
      <label for="input" class="block text-sm font-medium text-gray-700">Plain Text</label>
      <textarea id="input" rows="4" class="mt-1 block w-full border border-gray-300 rounded-md p-2 focus:outline-none focus:ring-2 focus:ring-blue-500"></textarea>
    </div>

    <div class="mb-4">
      <label for="key" class="block text-sm font-medium text-gray-700">Key</label>
      <input type="text" id="key" class="mt-1 block w-full border border-gray-300 rounded-md p-2 focus:outline-none focus:ring-2 focus:ring-blue-500">
    </div>

    <div class="flex justify-between mb-4">
      <button id="encryptBtn" class="bg-blue-500 text-white px-4 py-2 rounded-md hover:bg-blue-600 w-1/2 mr-2">Encrypt</button>
      <button id="decryptBtn" class="bg-green-500 text-white px-4 py-2 rounded-md hover:bg-green-600 w-1/2 ml-2">Decrypt</button>
    </div>

    <div class="mb-4">
      <label for="output" class="block text-sm font-medium text-gray-700">Output</label>
      <textarea id="output" rows="4" readonly class="mt-1 block w-full border border-gray-300 rounded-md p-2 bg-gray-100"></textarea>
    </div>
  </div>

  <script>
    function generateMatrix(key) {
      key = key.toUpperCase().replace(/J/g, "I").replace(/[^A-Z]/g, '');
      let matrix = [];
      let used = new Set();

      for (let char of key + "ABCDEFGHIKLMNOPQRSTUVWXYZ") {
        if (!used.has(char)) {
          matrix.push(char);
          used.add(char);
        }
      }

      let grid = [];
      for (let i = 0; i < 5; i++) {
        grid.push(matrix.slice(i * 5, i * 5 + 5));
      }

      return grid;
    }

    function findPosition(matrix, char) {
      for (let i = 0; i < 5; i++) {
        for (let j = 0; j < 5; j++) {
          if (matrix[i][j] === char) return [i, j];
        }
      }
      return null;
    }

    function prepareText(text) {
      text = text.toUpperCase().replace(/J/g, "I").replace(/[^A-Z]/g, '');
      let prepared = "";
      for (let i = 0; i < text.length; i++) {
        prepared += text[i];
        if (text[i] === text[i + 1]) {
          prepared += 'X';
        }
      }
      if (prepared.length % 2 !== 0) {
        prepared += 'X';
      }

      let pairs = [];
      for (let i = 0; i < prepared.length; i += 2) {
        pairs.push([prepared[i], prepared[i + 1]]);
      }
      return pairs;
    }

    function playfairEncrypt(text, key) {
      const matrix = generateMatrix(key);
      const pairs = prepareText(text);
      let result = "";

      for (let [a, b] of pairs) {
        let [row1, col1] = findPosition(matrix, a);
        let [row2, col2] = findPosition(matrix, b);

        if (row1 === row2) {
          result += matrix[row1][(col1 + 1) % 5];
          result += matrix[row2][(col2 + 1) % 5];
        } else if (col1 === col2) {
          result += matrix[(row1 + 1) % 5][col1];
          result += matrix[(row2 + 1) % 5][col2];
        } else {
          result += matrix[row1][col2];
          result += matrix[row2][col1];
        }
      }

      return result;
    }

    function playfairDecrypt(text, key) {
      const matrix = generateMatrix(key);
      const pairs = prepareText(text);
      let result = "";

      for (let [a, b] of pairs) {
        let [row1, col1] = findPosition(matrix, a);
        let [row2, col2] = findPosition(matrix, b);

        if (row1 === row2) {
          result += matrix[row1][(col1 + 4) % 5];
          result += matrix[row2][(col2 + 4) % 5];
        } else if (col1 === col2) {
          result += matrix[(row1 + 4) % 5][col1];
          result += matrix[(row2 + 4) % 5][col2];
        } else {
          result += matrix[row1][col2];
          result += matrix[row2][col1];
        }
      }

      return result;
    }

    document.getElementById('encryptBtn').addEventListener('click', () => {
      const text = document.getElementById('input').value;
      const key = document.getElementById('key').value;
      if (key.trim()) {
        document.getElementById('output').value = playfairEncrypt(text, key);
      } else {
        alert('Please enter a valid text key.');
      }
    });

    document.getElementById('decryptBtn').addEventListener('click', () => {
      const text = document.getElementById('input').value;
      const key = document.getElementById('key').value;
      if (key.trim()) {
        document.getElementById('output').value = playfairDecrypt(text, key);
      } else {
        alert('Please enter a valid text key.');
      }
    });
  </script>

</body>
</html>