public static byte[] ivCipherConcat(byte[] iv,byte[] cipherText){
  byte[] combined=new byte[iv.length + cipherText.length];
  System.arraycopy(iv,0,combined,0,iv.length);
  System.arraycopy(cipherText,0,combined,iv.length,cipherText.length);
  return combined;
}

public static byte [ ] ivCipherConcat ( byte [ ] iv , byte [ ] cipherText ) { byte [ ] combined = new byte [ iv . length + cipherText . length ] ; System . arraycopy ( iv , 0 , combined , 0 , iv . length ) ; System . arraycopy ( cipherText , 0 , combined , iv . length , cipherText . length ) ; return combined ; }
concatinate the iv to the ciphertext using array copy . this is used e . g . before computing mac .
