private static byte[] expandHrp(final String hrp) {
        int hrpLength = hrp.length();
        byte ret[] = new byte[hrpLength * 2 + 1];
        for (int i = 0; i < hrpLength; ++i) {
            int c = hrp.charAt(i) & 0x7f; // Limit to standard 7-bit ASCII
            ret[i] = (byte) ((c >>> 5) & 0x07);
            ret[i + hrpLength + 1] = (byte) (c & 0x1f);
        }
        ret[hrpLength] = 0;
        return ret;
    }
private static byte [ ] expandHrp ( final String hrp ) { int hrpLength = hrp . length ( ) ; byte ret [ ] = new byte [ hrpLength * 2 + 1 ] ; for ( int i = 0 ; i < hrpLength ; ++ i ) { int c = hrp . charAt ( i ) & 0x7f ; ret [ i ] = ( byte ) ( ( c > > > 5 ) & 0x07 ) ; ret [ i + hrpLength + 1 ] = ( byte ) ( c & 0x1f ) ; } ret [ hrpLength ] = 0 ; return ret ; }
Expand a HRP for use in checksum computation.