private static bool HasInvalidTimestamp(TransactionViewModel transactionViewModel) { if (transactionViewModel.GetAttachmentTimestamp() == 0) { return(transactionViewModel.GetTimestamp() < MinTimestamp && transactionViewModel.GetHash() != Hash.NullHash || transactionViewModel.GetTimestamp() > (TimeStamp.Now() / 1000) + MaxTimestampFuture); } return(transactionViewModel.GetAttachmentTimestamp() < MinTimestampMs || transactionViewModel.GetAttachmentTimestamp() > TimeStamp.Now() + MaxTimestampFutureMs); }