Method padding

security/src/main/java/pro/tools/security/sm/SM3.java:69–85

(byte[] source)

    }

    private static byte[] padding(byte[] source) throws IOException {
        long l = source.length * 8;
        long k = 448 - (l + 1) % 512;
        if (k < 0) {
            k = k + 512;
        }
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        baos.write(source);
        baos.write(FirstPadding);
        long i = k - 7;
        while (i > 0) {
            baos.write(ZeroPadding);
            i -= 8;
        }
        baos.write(long2bytes(l));
        return baos.toByteArray();
    }

    private static byte[] long2bytes(long l) {
        byte[] bytes = new byte[8];