invalid AES key length error

Question

this code give invalid AES key length error. how can i correct it ? ( i want 128 bit key AES encryption )

package org.temp2.cod1;
import java.security.*;

im         


        

Answer 1

You can't typically use any arbitrary key length (such as you're doing here with "supernova") for a block cipher like AES. You must use a supported key length (128, 192, 256, etc) appropriate for your algorithm of choice.

One common way to do this is to hash your passphrase (e.g., via SHA) and extract the first N bytes. This is better anyhow, as it allows you to "salt" your password with an initialization value such that no two users' "keys" are identical even if their passphrases are the same. If you're really interested in this stuff, the seminal work is Applied Cryptography by Bruce Schneier.

For practical implementation details, see