public static byte[] HMACSHA512(byte[] key, byte[] data)
{
var mac = new LushCoin.BouncyCastle.Crypto.Macs.HMac(new Sha512Digest());
mac.Init(new KeyParameter(key));
mac.Update(data);
byte[] result = new byte[mac.GetMacSize()];
mac.DoFinal(result, 0);
return(result);
}