question: public static byte [ ] decode ( byte [ ] data ) { int len = data . length / 4 * 3 ; ByteArrayOutputStream bOut = new ByteArrayOutputStream ( len ) ; try { encoder . decode ( data , 0 , data . length , bOut ) ; } catch ( Exception e ) { throw new DecoderException ( "unable to decode base64 data: " + e . getMessage ( ) , e ) ; } return bOut . toByteArray ( ) ; }
target:  decode the base 64 encoded input data. It is assumed the input data is valid.