What are the differences between the ROT13 and Caesar Algorithm in PHP encryption?

The ROT13 algorithm is a simple letter substitution cipher that replaces a letter with the letter 13 positions down the alphabet. The Caesar algorithm, on the other hand, allows for a customizable shift value for letter substitution. In PHP, the ROT13 algorithm is commonly implemented using the str_rot13() function, while the Caesar algorithm can be implemented by manually shifting the letters based on a specified key. 

// Implementing ROT13 encryption in PHP
$text = "Hello, World!";
$encrypted_text = str_rot13($text);
echo $encrypted_text;

// Implementing Caesar encryption with a shift of 3 in PHP
function caesarEncrypt($text, $shift){
    $result = "";
    $length = strlen($text);
    for($i = 0; $i < $length; $i++){
        $char = $text[$i];
        if(ctype_alpha($char)){
            $offset = ord(ctype_upper($char) ? 'A' : 'a');
            $result .= chr(fmod((ord($char) + $shift - $offset), 26) + $offset);
        } else {
            $result .= $char;
        }
    }
    return $result;
}

$text = "Hello, World!";
$encrypted_text = caesarEncrypt($text, 3);
echo $encrypted_text;

Keywords

ROT13 Caesar Algorithm PHP encryption cryptography security

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