arc4 encryption and decryption in php

ARC4.php

<?php
// RC4 encryption function
function ARC4($data, $key) {

    $s = array();
    $keyLength = strlen($key);

    if ($keyLength == 0) {
        return "";
    }

    $dataLength = strlen($data);
    $final = '';

    for ($i = 0; $i < 256; $i++) {
        $s[$i] = $i;
    }

    $j = 0;
    for ($i = 0; $i < 256; $i++) {
        $j = ($j + $s[$i] + ord($key[$i % $keyLength])) % 256;
        $temp = $s[$i];
        $s[$i] = $s[$j];
        $s[$j] = $temp;
    }

    $i = 0;
    $j = 0;
    for ($k = 0; $k < $dataLength; $k++) {
        $i = ($i + 1) % 256;
        $j = ($j + $s[$i]) % 256;
        $temp = $s[$i];
        $s[$i] = $s[$j];
        $s[$j] = $temp;
        $final .= $data[$k] ^ chr($s[($s[$i] + $s[$j]) % 256]);
    }

    return $final;

}


// Example usage
$data = "Hello, World!";
$key = "SecretKeyaaa";

// Encrypt the data using RC4
$encryptedData = ARC4($data, $key);

// Encode the encrypted data using Base64
$encodedData = base64_encode($encryptedData);

echo "Original Data: " . $data . "\n";
echo "Encrypted Data: " . $encryptedData . "\n";
echo "Encoded Data: " . $encodedData . "\n";

$decodedString = base64_decode($encodedData);
$decryptedData = ARC4($decodedString, $key);

echo "Original Data: " . $data . "\n";
echo "Decrypted Data: " . $decryptedData . "\n";

?>