Decryption is not working with AES 128 bit CBC in PHP

Question

I'm trying to encrypt and decrypt a token with the AES 128 bit CBC encryption in PHP. If I try to encrypt and decrypt a token, the result is not the original token. Here is my code:

$decrKey = "123456789abcdefg";
$decrIV = "xyz123456789abcd";

function encryptAES($data,$key,$iv)
{
$decr= mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, base64_encode($data), MCRYPT_MODE_CBC, $iv);    
return $decr;   
}    

function decryptAES($data,$key,$iv)
{
$decr= mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($data), MCRYPT_MODE_CBC, $iv);    
return $decr;   
}      

$token = "abcdefghijk";
echo $token;

$tokenEncrypt = encryptAES($token,$decrKey,$decrIV);
echo "encrypt: ".$tokenEncrypt ;

$tokenDecrypt = decryptAES($tokenEncrypt,$decrKey,$decrIV);
echo "decrypt: ".$tokenDecrypt ;

What do i miss?

Answer 1

You should base 64 encode the result of the encryption method (called the ciphertext), and decode it again before decryption. You are currently base 64 encoding the plain text in the encryption function instead of the ciphertext. Encoding the plain text is not necessary. It would be however a good idea to use a well defined character-encoding for the plain text.

$encr = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv));
return $encr