If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption. But the AES cipher can not. The following program demonstrates this.


import java.io.PrintStream;
import java.security.*;
import java.security.spec.*;
import java.util.Random;

import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.Provider;
import com.sun.advcrypto.provider.SunAES;

public class test {

     public static void main( String argv[] ) {
     try{
    
byte[] iv = null;
         String algorithm = "AES";
     String mode = "CBC";
    String padding = "NoPadding";
  int keyStrength=128;
  AlgorithmParameterSpec aps = null;
 
  Cipher ci = Cipher.getInstance( algorithm + "/" + mode + "/" + padding, "SunAES" );
 
  KeyGenerator kg = KeyGenerator.getInstance( algorithm, "SunAES" );
     kg.init(keyStrength);
     SecretKey key = kg.generateKey();

     ci.init( Cipher.ENCRYPT_MODE, key, aps);

     }catch(Exception ex){
     System.out.println("FAILED");
     ex.printStackTrace();
    
     }
     }
}


lwang:/home/lw129730/AES/testcode/test( 172 )%java test
FAILED
java.security.InvalidAlgorithmParameterException: Wrong parameter type: IV expected
        at cryptix.jce.provider.cipher.SunAES_j.b(DashoA6275)
        at cryptix.jce.provider.cipher.SunAES_i.a(DashoA6275)
        at cryptix.jce.provider.cipher.SunAES_h.a(DashoA6275)
        at cryptix.jce.provider.cipher.BlockCipher.engineInit(DashoA6275)
        at javax.crypto.Cipher.init(DashoA6275)
        at test.main(test.java:30)