question: public void init ( boolean forEncryption , CipherParameters param ) { core . init ( forEncryption , param ) ; if ( param instanceof ParametersWithRandom ) { ParametersWithRandom rParam = ( ParametersWithRandom ) param ; key = ( RSAKeyParameters ) rParam . getParameters ( ) ; random = rParam . getRandom ( ) ; } else { key = ( RSAKeyParameters ) param ; random = new SecureRandom ( ) ; } }
target:  initialise the RSA engine.