question: public static CipherParameters makePBEParameters ( PBEKeySpec keySpec , int type , int hash , int keySize , int ivSize ) { PBEParametersGenerator generator = makePBEGenerator ( type , hash ) ; byte [ ] key ; CipherParameters param ; key = convertPassword ( type , keySpec ) ; generator . init ( key , keySpec . getSalt ( ) , keySpec . getIterationCount ( ) ) ; if ( ivSize != 0 ) { param = generator . generateDerivedParameters ( keySize , ivSize ) ; } else { param = generator . generateDerivedParameters ( keySize ) ; } for ( int i = 0 ; i != key . length ; i ++ ) { key [ i ] = 0 ; } return param ; }
target:  construct a key and iv (if necessary) suitable for use with a  Cipher.