AES buffer size

I'm trying to adapt this DES encrypting example to AES, so I made the changes, and it try to run this:

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;

// Adapted from http://www.exampledepot.com/egs/javax.crypto/DesFile.html
public class AesEncrypter {

    private Cipher ecipher;
    private Cipher dcipher;

    // Buffer used to transport the bytes from one stream to another
    private byte[] buf = new byte[1024];

    public AesEncrypter(SecretKey key) throws Exception {
 // Create an 8-byte initialization vector
 byte[] iv = new byte[] { (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A };
 AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);

 ecipher = Cipher.getInstance("AES/CBC/NoPadding");
 dcipher = Cipher.getInstance("AES/CBC/NoPadding");

 // CBC requires an initialization vector
 ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
 dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
    }

    public void encrypt(InputStream in, OutputStream out) throws Exception {
 // Bytes written to out will be encrypted
 out = new CipherOutputStream(out, ecipher);

 // Read in the cleartext bytes and write to out to encrypt
 int numRead = 0;
 while ((numRead = in.read(buf)) >= 0) {
     out.write(buf, 0, numRead);
 }
 out.close();
    }

    public void decrypt(InputStream in, OutputStream out) throws Exception {
 // Bytes read from in will be decrypted
 in = new CipherInputStream(in, dcipher);

 // Read in the decrypted bytes and write the cleartext to out
 int numRead = 0;
 while ((numRead = in.read(buf)) >= 0) {
     out.write(buf, 0, numRead);
 }
 out.close();
    }

    public static void main(String[] args) throws Exception {
 System.out.println("Starting...");

 SecretKey key = KeyGenerator.getInstan开发者_高级运维ce("AES").generateKey();

 InputStream in = new FileInputStream(new File("/home/wellington/Livros/O Alienista/speechgen0001.mp3/"));
 OutputStream out = System.out;

 AesEncrypter encrypter = new AesEncrypter(key);
 encrypter.encrypt(in, out);

 System.out.println("Done!");
    }

}

but I got the Exception:

InvalidAlgorithmParameterException: Wrong IV length: must be 16 bytes long

So I tried to solve by changing the

AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);

for

AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv, 0, 16);

but results in

IV buffer too short for given offset/length combination

I can just go trying till it works, but I would like to hear from who work with AES what is the commonly used buffer size?

Your main question has been answered, but I'd like to add that you should not in general be using a fixed string IV unless you know what you're doing. You maybe also want to use PKCS5Padding instead of NoPadding.

I think it's saying it wants 16 bytes, but this is only 8 bytes:

byte[] iv = new byte[] {
  (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A
};

Maybe try this?

byte[] iv = new byte[] {
  (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A,
  (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A
};