PHP script for DES/CBC/ with PKCS5Padding encryption and decryption

Question

I would like to know in the following code if PKCS#5 padding is added ? If not how to add ?

$message = \"insert plaintext message here\";

$iv  = pack(\'H*\'         


        

Answer 1

No, it is not added. Unfortunately PHP / mcrypt uses zero padding until the message is N times the block size.

To add PKCS#5 padding, use the formula:

p = b - l % b

Where l is the message length, b is the block size and % is the remainder operation. Then add p bytes with the value p to the end before performing the encryption.