129 lines
2.9 KiB
PHP
129 lines
2.9 KiB
PHP
|
<?php
|
||
|
|
|
||
|
|
function generateCodeword($l) {
|
||
|
|
$codeword = "";
|
||
|
|
for ($i = 0; $i < $l; $i++){
|
||
|
|
$rand = rand(65, 116);
|
||
|
|
if ($rand > 90) {
|
||
|
|
$rand += 6;
|
||
|
|
}
|
||
|
|
$codeword .= chr($rand);
|
||
|
|
}
|
||
|
|
return $codeword;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function getLetterValue($char) {
|
||
|
|
return ord($char) - 33;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function getNumberValue($nr) {
|
||
|
|
return chr((($nr + 94) % 94) + 33);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function encodeChar($char, $offset) {
|
||
|
|
return getNumberValue(getLetterValue($char) + getLetterValue($offset));
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function decodeChar($char, $offset) {
|
||
|
|
return getNumberValue(getLetterValue($char) - getLetterValue($offset));
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function encode($codeword, $message) {
|
||
|
|
$encrypted = "";
|
||
|
|
for ($i = 0; $i < strlen($message); $i++) {
|
||
|
|
$encrypted .= encodeChar(substr($message, $i, 1), substr($codeword, $i % strlen($codeword), 1));
|
||
|
|
}
|
||
|
|
return $encrypted;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function hideCodeword($codeword, $message) {
|
||
|
|
$len = strlen($codeword);
|
||
|
|
$hidden = "";
|
||
|
|
for ($i = 0; $i < $len; $i++) {
|
||
|
|
$hidden .= substr($message, $i, 1);
|
||
|
|
$hidden .= substr($codeword, $i, 1);
|
||
|
|
}
|
||
|
|
$hidden .= substr($message, $len, strlen($message) - $len - 1);
|
||
|
|
$hidden .= chr(64 + $len);
|
||
|
|
$hidden .= substr($message, -1);
|
||
|
|
return $hidden;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function encrypt($message) {
|
||
|
|
$cw = generateCodeword(rand(7, 14));
|
||
|
|
return hideCodeword($cw, encode($cw, $message));
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
function decrypt($code) {
|
||
|
|
$len = ord(substr($code, -2, 1)) - 64;
|
||
|
|
$code = substr($code, 0, -2) . substr($code, -1);
|
||
|
|
$codedMessage = "";
|
||
|
|
$codeword = "";
|
||
|
|
for ($i = 0; $i < (2 * $len); $i += 2) {
|
||
|
|
$codedMessage .= substr($code, $i, 1);
|
||
|
|
$codeword .= substr($code, $i + 1, 1);
|
||
|
|
}
|
||
|
|
$codedMessage .= substr($code, 2 * $len);
|
||
|
|
$decrypted = "";
|
||
|
|
for ($i = 0; $i < strlen($codedMessage); $i++) {
|
||
|
|
$decrypted .= decodeChar(substr($codedMessage, $i, 1), substr($codeword, $i % strlen($codeword), 1));
|
||
|
|
}
|
||
|
|
return $decrypted;
|
||
|
|
}
|
||
|
|
|
||
|
|
?>
|
||
|
|
|
||
|
|
|
||
|
|
<?php
|
||
|
|
|
||
|
|
if(isset($_POST['encode'])) {
|
||
|
|
$encode = $_POST['encode'];
|
||
|
|
if (strlen($encode) < 16) {
|
||
|
|
$decode = "An input string must at least be 16 characters...";
|
||
|
|
} else {
|
||
|
|
$decode = encrypt($encode);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
?>
|
||
|
|
<!DOCTYPE html>
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<title>Encryption/Decryption tool</title>
|
||
|
|
<meta author="Benjamin Ver"/>
|
||
|
|
<!-- Kudos to 16yo Benjamin for this site and the idea for the encryption. -->
|
||
|
|
<style type="text/css">
|
||
|
|
.FFCG { font-family: "Century Gothic"; }
|
||
|
|
#decode { <?php if (strlen($encode) < 16) { echo 'color: red;'; } ?> }
|
||
|
|
</style>
|
||
|
|
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<table align="center">
|
||
|
|
<th colspan="2" class="FFCG">Encryption/Decryption tool</th>
|
||
|
|
<tr>
|
||
|
|
<td class="FFCG">Coderen:</td>
|
||
|
|
<td class="FFCG">Decoderen:</td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<form action="decrypt.php" method="POST">
|
||
|
|
<td><textarea name="encode" style="width: 500px; height: 150px" class="FFCG"><?php echo $encode; ?></textarea></td>
|
||
|
|
<td><textarea id="decode" name="decode" style="width: 500px; height: 150px" class="FFCG" readonly><?php echo $decode; ?></textarea></td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<td colspan="2">
|
||
|
|
<input type="submit" value="encode" class="FFCG"></td>
|
||
|
|
</tr>
|
||
|
|
</form>
|
||
|
|
</table>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|