using System;

using System.Text;

using System.Security.Cryptography;

public class Program

{

    public static void Main()

    {

        // operationReference = hex(md5(systemId + recordId + epoch))

​

        int systemId = 7;

        string recordId = "73194257";

        long epoch = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();

​

​

        var valueAsBytes = Encoding.UTF8.GetBytes($"{systemId}{recordId}{epoch}");

        using var md5 = MD5.Create();

        var hashBytes = md5.ComputeHash(valueAsBytes);

​

        var asHex = string.Join(string.Empty, Array.ConvertAll(hashBytes, b => b.ToString("x2")));

​

        Console.WriteLine(asHex);

    }

}