CHIPER/polyalphabetic_cipher.html at main · KIRAN-KUMAR-K3/CHIPER · 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>Polyalphabetic Cipher</title>
    <link href="https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600&display=swap" rel="stylesheet">
    <style>
        /* General styling */
        body {
            font-family: 'Poppins', sans-serif;
            margin: 0;
            padding: 0;
            background: linear-gradient(135deg, #6a11cb, #2575fc);
            color: #fff;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            height: 100vh;
        }

        h1 {
            font-size: 2.5rem;
            text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.3);
            margin-bottom: 20px;
        }

        /* Container for input area */
        .container {
            background: rgba(0, 0, 0, 0.7);
            padding: 30px;
            border-radius: 15px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.4);
            width: 100%;
            max-width: 600px;
            text-align: center;
        }

        textarea {
            width: 100%;
            height: 150px;
            padding: 15px;
            border-radius: 10px;
            border: none;
            font-size: 1.1rem;
            color: #264653;
            background-color: #f1faee;
            margin-bottom: 20px;
            resize: none;
        }

        input[type="text"] {
            padding: 10px;
            width: 100%;
            font-size: 1rem;
            margin-top: 10px;
            border-radius: 8px;
            border: none;
            background-color: #f1faee;
            color: #264653;
        }

        button {
            padding: 10px 20px;
            background-color: #e9c46a;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            font-size: 1.1rem;
            color: #264653;
            transition: background-color 0.3s, transform 0.3s;
        }

        button:hover {
            background-color: #f4a261;
            transform: scale(1.05);
        }

        .result {
            margin-top: 20px;
            font-size: 1.3rem;
            background: #264653;
            padding: 15px;
            border-radius: 10px;
            color: #f1faee;
            min-height: 50px;
            word-wrap: break-word;
        }
    </style>
</head>
<body>
  <h1>Polyalphabetic Cipher</h1>
  <div class="container">
    <textarea id="inputText" placeholder="Enter text..."></textarea>
    <input type="text" id="keyInput" placeholder="Enter cipher key" value="KEY">
    <br>
    <button onclick="encryptText()">Encrypt</button>
    <button onclick="decryptText()">Decrypt</button>
    <div class="result" id="result"></div>
    <div class="time" id="timeTaken"></div>
  </div>

  <script>
    const alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    const base = alphabet.length; // 62 characters

    function encryptText() {
      processText(true);
    }

    function decryptText() {
      processText(false);
    }

    function processText(isEncrypt) {
      let key = document.getElementById("keyInput").value.replace(/[^A-Za-z0-9]/g, "");
      let inputText = document.getElementById("inputText").value;
      let resultText = "";
      let keyIndex = 0;

      if (key === "") {
        document.getElementById("result").innerText = "Please enter a valid key.";
        return;
      }

      let startTime = performance.now();

      for (let i = 0; i < inputText.length; i++) {
        let char = inputText[i];
        let charPos = alphabet.indexOf(char);

        if (charPos === -1) {
          // Non-alphanumeric → keep as is
          resultText += char;
        } else {
          let keyChar = key[keyIndex % key.length];
          let keyShift = alphabet.indexOf(keyChar);
          if (isEncrypt) {
            resultText += alphabet[(charPos + keyShift) % base];
          } else {
            resultText += alphabet[(charPos - keyShift + base) % base];
          }
          keyIndex++;
        }
      }

      let endTime = performance.now();
      let timeTaken = (endTime - startTime).toFixed(4);

      document.getElementById("result").innerText = resultText || "Please enter valid text.";
      document.getElementById("timeTaken").innerText = "Time taken: " + timeTaken + " ms";
    }
  </script>
</body>
</html>