using System;

using System.Security.Cryptography;

using System.Text;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        const string PublicKey = "eQQR7oqFcO3JqpYPJzla";

        const string PrivateKey = "1W4iZHuS93WqBzuzGEiT";

        var CustomerAccountNumber = "01";

        var MSISDN = "201220247177";

        var OperatorCode = "60201";

        var SubscriptionPlanId = 82283;

        var InitialPaymentProductId = "EgyMob-RE";

        var InitialPaymentDate = "2021-09-15 12:00:00Z";

        var ExecuteInitialPaymentNow = false;

        var RecurringPaymentProductId = "EgyMob-RE";

        var ProductCatalogName = "orangedirectbilling192021";

        var ExecuteRecurringPaymentNow = false;

        var ContractStartDate = "2021-09-15 12:00:00Z";

        var ContractEndDate = "2022-09-15 12:00:00Z";

        var AutoRenewContract = true;

        var Language = 1;

        var SendVerificationSMS = true;

        var allowMultipleFreeStartPeriods = true;

        var HeaderEnrichmentReferenceCode = "";

        var SmsId = "";

        var message = CustomerAccountNumber + MSISDN + OperatorCode + SubscriptionPlanId.ToString() + InitialPaymentProductId + InitialPaymentDate + ExecuteInitialPaymentNow.ToString().ToLower() + RecurringPaymentProductId + ProductCatalogName + ExecuteRecurringPaymentNow.ToString().ToLower() + ContractStartDate + ContractEndDate + AutoRenewContract.ToString().ToLower() + Language.ToString() + SendVerificationSMS.ToString().ToLower() + allowMultipleFreeStartPeriods.ToString().ToLower() + HeaderEnrichmentReferenceCode + SmsId;

        var digest = CalculateDigest(PublicKey, PrivateKey, message);

        Console.WriteLine(digest);

​

    }

​

    public static string CalculateDigest(string publicKey, string privateKey, string message)

    {

        var digest = "";

        var hash = new System.Security.Cryptography.HMACSHA256(System.Text.Encoding.UTF8.GetBytes(privateKey));

        var correctHash = string.Join(string.Empty, hash.ComputeHash(System.Text.Encoding.UTF8.GetBytes(message)).Select(b => b.ToString("x2")));

        digest = publicKey + ":" + correctHash;

        return digest;

    }

}