[c#] how to generate a unique token which expires after 24 hours?

I like Guffa's answer and since I can't comment I will provide the answer Udil's question here.

I needed something similar but I wanted certein logic in my token, I wanted to:

  1. See the expiration of a token
  2. Use a guid to mask validate (global application guid or user guid)
  3. See if the token was provided for the purpose I created it (no reuse..)
  4. See if the user I send the token to is the user that I am validating it for

Now points 1-3 are fixed length so it was easy, here is my code:

Here is my code to generate the token:

public string GenerateToken(string reason, MyUser user)
{
    byte[] _time     = BitConverter.GetBytes(DateTime.UtcNow.ToBinary());
    byte[] _key      = Guid.Parse(user.SecurityStamp).ToByteArray();
    byte[] _Id       = GetBytes(user.Id.ToString());
    byte[] _reason   = GetBytes(reason);
    byte[] data       = new byte[_time.Length + _key.Length + _reason.Length+_Id.Length];

    System.Buffer.BlockCopy(_time, 0, data, 0, _time.Length);
    System.Buffer.BlockCopy(_key , 0, data, _time.Length, _key.Length);
    System.Buffer.BlockCopy(_reason, 0, data, _time.Length + _key.Length, _reason.Length);
    System.Buffer.BlockCopy(_Id, 0, data, _time.Length + _key.Length + _reason.Length, _Id.Length);

    return Convert.ToBase64String(data.ToArray());
}

Here is my Code to take the generated token string and validate it:

public TokenValidation ValidateToken(string reason, MyUser user, string token)
{
    var result = new TokenValidation();
    byte[] data     = Convert.FromBase64String(token);
    byte[] _time     = data.Take(8).ToArray();
    byte[] _key      = data.Skip(8).Take(16).ToArray();
    byte[] _reason   = data.Skip(24).Take(2).ToArray();
    byte[] _Id       = data.Skip(26).ToArray();

    DateTime when = DateTime.FromBinary(BitConverter.ToInt64(_time, 0));
    if (when < DateTime.UtcNow.AddHours(-24))
    {
        result.Errors.Add( TokenValidationStatus.Expired);
    }
    
    Guid gKey = new Guid(_key);
    if (gKey.ToString() != user.SecurityStamp)
    {
        result.Errors.Add(TokenValidationStatus.WrongGuid);
    }

    if (reason != GetString(_reason))
    {
        result.Errors.Add(TokenValidationStatus.WrongPurpose);
    }

    if (user.Id.ToString() != GetString(_Id))
    {
        result.Errors.Add(TokenValidationStatus.WrongUser);
    }
    
    return result;
}

private static string GetString(byte[] reason) => Encoding.ASCII.GetString(reason);

private static byte[] GetBytes(string reason) => Encoding.ASCII.GetBytes(reason);

The TokenValidation class looks like this:

public class TokenValidation
{
    public bool Validated { get { return Errors.Count == 0; } }
    public readonly List<TokenValidationStatus> Errors = new List<TokenValidationStatus>();
}

public enum TokenValidationStatus
{
    Expired,
    WrongUser,
    WrongPurpose,
    WrongGuid
}

Now I have an easy way to validate a token, no Need to Keep it in a list for 24 hours or so. Here is my Good-Case Unit test:

private const string ResetPasswordTokenPurpose = "RP";
private const string ConfirmEmailTokenPurpose  = "EC";//change here change bit length for reason  section (2 per char)

[TestMethod]
public void GenerateTokenTest()
{
    MyUser user         = CreateTestUser("name");
    user.Id             = 123;
    user.SecurityStamp  = Guid.NewGuid().ToString();
    var token   = sit.GenerateToken(ConfirmEmailTokenPurpose, user);
    var validation    = sit.ValidateToken(ConfirmEmailTokenPurpose, user, token);
    Assert.IsTrue(validation.Validated,"Token validated for user 123");
}

One can adapt the code for other business cases easely.

Happy Coding

Walter

Examples related to c#

How can I convert this one line of ActionScript to C#? Microsoft Advertising SDK doesn't deliverer ads How to use a global array in C#? How to correctly write async method? C# - insert values from file into two arrays Uploading into folder in FTP? Are these methods thread safe? dotnet ef not found in .NET Core 3 HTTP Error 500.30 - ANCM In-Process Start Failure Best way to "push" into C# array

Examples related to asp.net

RegisterStartupScript from code behind not working when Update Panel is used You must add a reference to assembly 'netstandard, Version=2.0.0.0 No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization How to use log4net in Asp.net core 2.0 Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state How to create roles in ASP.NET Core and assign them to users? How to handle Uncaught (in promise) DOMException: The play() request was interrupted by a call to pause() ASP.NET Core Web API Authentication Could not load file or assembly 'CrystalDecisions.ReportAppServer.CommLayer, Version=13.0.2000.0 WebForms UnobtrusiveValidationMode requires a ScriptResourceMapping for jquery

Examples related to wcf

Create a asmx web service in C# using visual studio 2013 WCF Exception: Could not find a base address that matches scheme http for the endpoint WCF Service, the type provided as the service attribute values…could not be found WCF error - There was no endpoint listening at How can I pass a username/password in the header to a SOAP WCF Service The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'NTLM' Content Type application/soap+xml; charset=utf-8 was not supported by service The content type application/xml;charset=utf-8 of the response message does not match the content type of the binding (text/xml; charset=utf-8) maxReceivedMessageSize and maxBufferSize in app.config how to generate a unique token which expires after 24 hours?

Examples related to authentication

Set cookies for cross origin requests How Spring Security Filter Chain works What are the main differences between JWT and OAuth authentication? http post - how to send Authorization header? ASP.NET Core Web API Authentication Token based authentication in Web API without any user interface Custom Authentication in ASP.Net-Core Basic Authentication Using JavaScript Adding ASP.NET MVC5 Identity Authentication to an existing project LDAP: error code 49 - 80090308: LdapErr: DSID-0C0903A9, comment: AcceptSecurityContext error, data 52e, v1db1

Examples related to token

Sending the bearer token with axios JWT (JSON Web Token) library for Java Python requests library how to pass Authorization header with single token best practice to generate random token for forgot password syntax error: unexpected token < What is the difference between a token and a lexeme? how to generate a unique token which expires after 24 hours? Parse (split) a string in C++ using string delimiter (standard C++) How do I fix a "Expected Primary-expression before ')' token" error? How can a Jenkins user authentication details be "passed" to a script which uses Jenkins API to create jobs?