I can encrypt data but cannot decrypt - php

Question

I can successfully encrypt passed data but sadly cannot decrypt it. What is wrong with my decrypt() function? Maybe it is something with my Initialization Vector(iv). Here is my code:
function pad($data, $size) {
$length = $size - strlen($data) % $size;
return $data . str_repeat(chr($length), $length);
}
function unpad($data) {
return substr($data, 0, -ord($data[strlen($data) - 1]));
}
//CORRECT ENCRYPTION METHOD
function encrypt($data) {
$key = "SiadajerSiadajer";
$iv_size = 16;
$iv = openssl_random_pseudo_bytes($iv_size, $strong);
$encryptedData = openssl_encrypt(pad($data, 16), 'AES-256-CBC', $key, OPENSSL_RAW_DATA, $iv);
$joinedData = hex2bin(bin2hex($iv).bin2hex($encryptedData));
$encodedJoinedData = base64_encode($joinedData);
return $encodedJoinedData;
}
//WRONG DECRYPTION FUNCTION
function decrypt($encodedJoinedData){
$key = "SiadajerSiadajer";
$DecodedData = base64_decode($encodedJoinedData);
$size = strlen($DecodedData);
$cipheredsize = $size - 16;
$iv = substr($DecodedData, 0, 16);
$halfDecryptedData = substr($DecodedData, 16, $size);
$decryptedData = openssl_decrypt(unpad($halfDecryptedData, 16), 'AES-256-CBC', $key, OPENSSL_RAW_DATA, $iv);
return $decryptedData;
}
$test = encrypt("sssss");
print $test;
$test2 = decrypt($test);
print $test2;

Answer 1

In the encrypt-method replace the line
$joinedData = hex2bin(bin2hex($iv).bin2hex($encryptedData));
with
$joinedData = $iv.$encryptedData;
because the conversions in the previous expression are unnecessary. This replacement doesn't change the result.
A possible solution for the decryption-part could be:
function decrypt($encodedJoinedData) {
$joinedData = base64_decode($encodedJoinedData);
$iv = substr($joinedData, 0, 16);
$encryptedData = substr($joinedData, 16);
$key = "SiadajerSiadajer";
$decryptedData = openssl_decrypt($encryptedData, 'AES-256-CBC', $key, OPENSSL_RAW_DATA, $iv);
$unpaddedData = unpad($decryptedData);
return $unpaddedData;
}