Encryption/starter.html at master · CS3550/Encryption · GitHub

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<!doctype html>
<html>

<head>
  <title>Javascript Practice</title>
  <style>
    html{
        text-align:center;
      }
      h1{
        border-radius:10px;
        padding:1rem;
        width:25%;
        margin-left:auto;
        margin-right:auto;
        box-shadow: 0px 0px 10px grey;
      }

      .main-content{
        border-radius:10px;
        padding:1rem;
        width:25%;
        margin-left:auto;
        margin-right:auto;
        box-shadow: 0px 0px 10px grey;
      }

      textarea{
        margin:1rem;
      }

      .explanation{
        color:gray;
        margin:.5rem;
        font-family:sans-serif;
        font-size:.8rem;
      }
    </style>
</head>

<body>
  <h1>Encryption</h1>
  <div class="main-content">
    <div>Insert your text to convert:</div>

    <div><textarea type="text" id="plainText">STarting Text !@#$%^&*(){</textarea></div>

      <div>Insert your encryption key</div>
      <div><textarea type="text" id="key1">1,2,3</textarea></div>
      <div>Insert your decryption key</div>
      <div><textarea type="text" id="key2">0,0,0</textarea></div>


    <div><button id="convertButton" onclick="clickEvent()">Start</button></div>

    <div class="explanation">Remove non-alpha characters and convert to lower case.</div>

    <div><p id="convertedText">?</p></div>

    <div class="explanation">Convert letters to numbers [0-25].</div>

    <div><p id="numericArray">?</p></div>

    <div class="explanation">Add the key to each number and mod 26.</div>

    <div><p id="encryptedNumbers">?</p></div>

    <div class="explanation">Convert encrypted numbers back to letters a-z.</div>

    <div><p id="encryptedCharacters">?</p></div>

    <div class="explanation">---</div>
    <div class="explanation">Reverse the process to get the plain text</div>
    <div class="explanation">---</div>

    <div class="explanation">Convert the letters to numbers [0-25]</div>

    <div><p id="postencryptionNumbers">?</p></div>

    <div class="explanation">Subtract the key and mod 26.</div>

    <div><p id="decryptedNumbers">?</p></div>

    <div class="explanation">Convert the numbers to letters a-z.</div>

    <div><p id="decryptedCharacters">?</p></div>
  </div>
  <script>

    function clickEvent() {
      var startText;
      var key1;
      var key2;
      var cleanText = "";
      var numeric = [];
      var encryptedNumbers = [];
      var encryptedCharacters = "";
      var postencryptionNumbers = [];
      var decryptedNumbers = [];
      var decryptedCharacters = "";

      var key = 3;

      //Do stuff

      startText = document.getElementById("plainText").value.toLowerCase();
      key1 = document.getElementById("key1").value.split(",");
      key2 = document.getElementById("key2").value.split(",");

      for (var i = 0; i < startText.length; i++) {
        var c = startText[i];
        if (/[a-z]/.test(c)) {
          cleanText += c;
        }
      }

      console.log("start:" + startText);
      console.log("end:" + cleanText);

      document.getElementById("convertedText").innerHTML = cleanText;

      var numeric = [];

      for (var i = 0; i < cleanText.length; i++) {
        numeric.push(cleanText.charCodeAt(i) - "a".charCodeAt(0));
      }

      document.getElementById("numericArray").innerHTML = numeric;

      var keyInc = 0;
      for (var i = 0; i < numeric.length; i++) {

        encryptedNumbers.push((numeric[i] + (+key1[keyInc])) % 26);
        keyInc++;
        if(keyInc >= key1.length)
          keyInc = 0;

      }

      document.getElementById("encryptedNumbers").innerHTML = encryptedNumbers;

      for (var i = 0; i < encryptedNumbers.length; i++) {
        encryptedCharacters += String.fromCharCode(encryptedNumbers[i] + "a".charCodeAt(0));
      }

      document.getElementById("encryptedCharacters").innerHTML = encryptedCharacters;


      for (var i = 0; i < encryptedCharacters.length; i++) {
        postencryptionNumbers.push(encryptedCharacters.charCodeAt(i) - "a".charCodeAt(0));
      }

      document.getElementById("postencryptionNumbers").innerHTML = postencryptionNumbers;

      keyInc = 0;
      for (var i = 0; i < postencryptionNumbers.length; i++) {

        var decryptedNumber = postencryptionNumbers[i] + (+key2[keyInc]);
        if(decryptedNumber < 0)
          decryptedNumber += 26;
        if(decryptedNumber >=26)
          decryptedNumber -= 26;

        keyInc++;
        if(keyInc >= key2.length)
          keyInc = 0;

        decryptedNumbers.push(decryptedNumber);
      }

      document.getElementById("decryptedNumbers").innerHTML = decryptedNumbers;

      for (var i = 0; i < decryptedNumbers.length; i++) {
        decryptedCharacters += String.fromCharCode(decryptedNumbers[i] + "a".charCodeAt(0));
      }

      document.getElementById("decryptedCharacters").innerHTML = decryptedCharacters;
    }

  </script>
</body>

</html>