How to do AES256 decryption in PHP?

Question

I have an encrypted bit of text that I need to decrypt. It\'s encrypted with AES-256-CBC. I have the encrypted text, key, and iv. However, no matter what I try I just can\'t

Answer 1

I'm not terribly familiar with this stuff, but it seems like trying MCRYPT_RIJNDAEL_256 in place of MCRYPT_RIJNDAEL_128 would be an obvious next step...

Edit: You're right -- this isn't what you need. MCRYPT_RIJNDAEL_128 is in fact the right choice. According to the link you provided, your key and IV are twice as long as they should be:

// How do you do 256-bit AES encryption in PHP vs. 128-bit AES encryption???
// The answer is:  Give it a key that's 32 bytes long as opposed to 16 bytes long.
// For example:
$key256 = '12345678901234561234567890123456';
$key128 = '1234567890123456';

// Here's our 128-bit IV which is used for both 256-bit and 128-bit keys.
$iv =  '1234567890123456';