mcrypt_decrypt在解密文本末尾添加null

Question

I used Rijndael algorithm to encrypt and decrypt my database password. I kept encoded password in another file. Here I reduced the code to get relevant :

$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, PASSWORD_SALT, 'mypassword', MCRYPT_MODE_ECB);    
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, PASSWORD_SALT, $encrypted, MCRYPT_MODE_ECB);
// !! The value of $decrypted is "mypassword      " i.e. "mypasswordNULLNULLNULLNULLNULL"

'mypassword' is converted to 'mypassword' + 6xNULL. The decrypted code is containing null.

I wrote this code 1 year ago and everything was working fine. But now, when version of all technologies have changed, I am having problem.

Answer 1

It was always so.

According to documentation:

The data that will be decrypted with the given cipher and mode. If the size of the data is not n * blocksize, the data will be padded with '\0'.

So either you trim your data with \0, or you have to store the original length anywhere and then cut the padded 0 off.