avsmithy/paxton-covert.html

## paxton-covert.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Paxton Fob converter</title>
<style>
table, th, td, div {
  border: 1px solid black;
}
td {
  min-width: 100px;
}
input, select,div, form, table  {
  margin:  5px;
  padding:  5px;
}
</style>
</head>
<body>
  <h1>Paxton Fob Conversion</h1>

  <p>
    This page can be used to convert the data on a paxton fob to a 8 byte id suitable for emulating as a EM41X id and vice versa. It was written by natmchugh https://github.com/natmchugh. It uses only client side JavaScript and so you can use the page here or save it and run it locally, enjoy!
  </p>
  <p>
    The source code for this page can be found at https://gist.githubusercontent.com/natmchugh/e8f08350a606dc68bbffbc0f6c44017b/raw/paxton-covert.html
  </p>
  <div>
    <h2>Convert page 4 and 5 of data from a paxton tag to an ID</h2>
    <form onsubmit="convertToEm41x()">
        <label for="page4">Page 4:</label><br>
        <input id="page4"><br>
        <label for="page5">Page 5:</label><br>
        <input id="page5"><br>
      <input type="submit" value="Convert"><br>
    </form>
      <table style="border:1px solid black">
      <tr>
        <td>Decimal</td><td id="em41x_dec"></td>
      </tr>
      <tr>
        <td>Hex</td><td id="em41x_hex"></td>
      </tr>
    </table>
    <br/>
  </div>

  <div>
  <h2>Convert from an ID to the equivalent data on page 4 and 5 of a paxton fob</h2>
  <form onsubmit="convertPaxton()">
      <label for="id">Id:</label><br>
      <input id="id"><br>
      <label for="type">Type:</label><br>
      <select id="type">
          <option value="6">iso card</option>
          <option value="3">fob</option>
          <option value="2">iso magstripe</option>
      </select><br>
    <input type="submit" value="Convert">
  </form>
    <table style="border:1px solid black">
    <tr>
      <td>Page 4</td><td id="page4_result"></td>
    </tr>
    <tr>
      <td>Page 5</td><td id="page5_result"></td>
    </tr>
  </table>
  </div>
</body>
</html>

<script>
  function convertToEm41x() {
  const page4 = document.getElementById('page4').value.replace(/ /g,'');
  const page5 = document.getElementById('page5').value.replace(/ /g,'');
  let  hex = BigInt('0x'+page4+page5);
  let num = i = 0n;
  let output = 0n;
  let skip = 64n;
  let digit = '';
  let mask = BigInt('0xF800000000000000');
  while (i < 8n) {
    num = hex & mask;
    skip -= 5n;
    mask = mask >> 5n;
    digit = (num >> skip & 15n);
    output = (output * 10n ) + digit;
    if (i === 5n)
    {
       skip -= 2n;
       mask = mask >> 2n;
    }
    i++;
}
  document.getElementById('em41x_dec').innerHTML = (output.toString(10));
  document.getElementById('em41x_hex').innerHTML = (output.toString(16));
  event.preventDefault();
}
function getParity(n)
{
  return ~(((BigInt(n) * BigInt("0x0101010101010101")) & BigInt("0x8040201008040201")) % BigInt("0x1FF")) & 1n;
}

function convertPaxton() {
  event.preventDefault();
  const em41x = document.getElementById('id').value.replace(/ /g,'').padStart(8, 0);
  const type = document.getElementById('type').value;
  let result = 0n;
  em41x.split('').forEach(
    (digit, index) => {
      dec = BigInt(digit)
      dec = (getParity(dec) << 4n) + dec;
      result = (result << 5n) + BigInt(dec);
      if (index == 5) { result = result << 2n; }
    }
  );
  result = (result << 22n) + 4128768n + BigInt(type);

  document.getElementById('page4_result').innerHTML = result.toString(16).substr(0, 8);
  document.getElementById('page5_result').innerHTML = result.toString(16).substr(8, 16);
  event.preventDefault();
}

</script>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width">
	<title>Paxton Fob converter</title>
	<style>
	table, th, td, div {
	border: 1px solid black;
	}
	td {
	min-width: 100px;
	}
	input, select,div, form, table {
	margin: 5px;
	padding: 5px;
	}
	</style>
	</head>
	<body>
	<h1>Paxton Fob Conversion</h1>

	<p>
	This page can be used to convert the data on a paxton fob to a 8 byte id suitable for emulating as a EM41X id and vice versa. It was written by natmchugh https://github.com/natmchugh. It uses only client side JavaScript and so you can use the page here or save it and run it locally, enjoy!
	</p>
	<p>
	The source code for this page can be found at https://gist.githubusercontent.com/natmchugh/e8f08350a606dc68bbffbc0f6c44017b/raw/paxton-covert.html
	</p>
	<div>
	<h2>Convert page 4 and 5 of data from a paxton tag to an ID</h2>
	<form onsubmit="convertToEm41x()">
	<label for="page4">Page 4:</label><br>
	<input id="page4"><br>
	<label for="page5">Page 5:</label><br>
	<input id="page5"><br>
	<input type="submit" value="Convert"><br>
	</form>
	<table style="border:1px solid black">
	<tr>
	<td>Decimal</td><td id="em41x_dec"></td>
	</tr>
	<tr>
	<td>Hex</td><td id="em41x_hex"></td>
	</tr>
	</table>
	<br/>
	</div>

	<div>
	<h2>Convert from an ID to the equivalent data on page 4 and 5 of a paxton fob</h2>
	<form onsubmit="convertPaxton()">
	<label for="id">Id:</label><br>
	<input id="id"><br>
	<label for="type">Type:</label><br>
	<select id="type">
	<option value="6">iso card</option>
	<option value="3">fob</option>
	<option value="2">iso magstripe</option>
	</select><br>
	<input type="submit" value="Convert">
	</form>
	<table style="border:1px solid black">
	<tr>
	<td>Page 4</td><td id="page4_result"></td>
	</tr>
	<tr>
	<td>Page 5</td><td id="page5_result"></td>
	</tr>
	</table>
	</div>
	</body>
	</html>

	<script>
	function convertToEm41x() {
	const page4 = document.getElementById('page4').value.replace(/ /g,'');
	const page5 = document.getElementById('page5').value.replace(/ /g,'');
	let hex = BigInt('0x'+page4+page5);
	let num = i = 0n;
	let output = 0n;
	let skip = 64n;
	let digit = '';
	let mask = BigInt('0xF800000000000000');
	while (i < 8n) {
	num = hex & mask;
	skip -= 5n;
	mask = mask >> 5n;
	digit = (num >> skip & 15n);
	output = (output * 10n ) + digit;
	if (i === 5n)
	{
	skip -= 2n;
	mask = mask >> 2n;
	}
	i++;
	}
	document.getElementById('em41x_dec').innerHTML = (output.toString(10));
	document.getElementById('em41x_hex').innerHTML = (output.toString(16));
	event.preventDefault();
	}
	function getParity(n)
	{
	return ~(((BigInt(n) * BigInt("0x0101010101010101")) & BigInt("0x8040201008040201")) % BigInt("0x1FF")) & 1n;
	}

	function convertPaxton() {
	event.preventDefault();
	const em41x = document.getElementById('id').value.replace(/ /g,'').padStart(8, 0);
	const type = document.getElementById('type').value;
	let result = 0n;
	em41x.split('').forEach(
	(digit, index) => {
	dec = BigInt(digit)
	dec = (getParity(dec) << 4n) + dec;
	result = (result << 5n) + BigInt(dec);
	if (index == 5) { result = result << 2n; }
	}
	);
	result = (result << 22n) + 4128768n + BigInt(type);

	document.getElementById('page4_result').innerHTML = result.toString(16).substr(0, 8);
	document.getElementById('page5_result').innerHTML = result.toString(16).substr(8, 16);
	event.preventDefault();
	}

	</script>