if( log.level >= 5 ) {
            log.println( "update: " + updates + " " + offset + ":" + len );
            Hexdump.hexdump( log, input, offset, Math.min( len, 256 ));
            log.flush();
        }
        if( len == 0 ) {
            return; /* CRITICAL */
        }
        digest.update( input, offset, len );
        updates++;
    }
    public byte[] digest() {
        byte[] b;