AES-256 encryption in Java without changing policy files

Question

I am trying to encrypt some data with AES in java.
Till now I have successfully encrypted the data with a 128 bit key.

For 256 bit encryption I need to change my policy files which is not an option for me.
I referred this SO Q/A too.
Tried BouncyCastle but it seems they don't have any provision for 256 bit keys( 1st question here ).
Had a look at JNCryptor. But don't know if its a good source or not.(BouncyCastle is approved by FIPS)

Also Reflection is not an option since it violates JAVA licence agreement.
So if someone could guide me to the relevant question or share a possible solution I'll be glad.

Answer 1

There is nothing wrong or insecure about a 128-bit AES key, it is not brute forcible. A 256-bit is not going to provide anymore security, a successful attack will be in another area.

The thing to make sure of is the quality of the key, use a cryptographically secure random number generator (CSPRNG) or derive the key from a really good password with PBKDF2.

Properly authenticate the encryption: encrypt and then MAC.

Use a random IV in CBC mode and do not report padding errors.