How to Store Tokens in ASP.NET Core Identity

How To Store Tokens in ASP.NET Core Identity Database Table

In this article, I will discuss How to Store Tokens in ASP.NET Core Identity Database Table. Please read our previous article discussing How to Implement the Forgot Password in ASP.NET Core Identity.

Why are the Generate Password Reset Tokens not stored in the AspNetUserTokens Table?

The password reset tokens in ASP.NET Core Identity are not stored in the AspNetUserTokens table for a few key reasons:

  • Security and Privacy: Password reset tokens are sensitive pieces of information. Storing them in a database, even temporarily, increases the risk of them being accessed by unauthorized parties. In the event of a database breach, having these tokens stored could lead to account compromise.
  • One-Time Use and Expiry: Password reset tokens are typically designed for one-time use and have a short expiration period. Once used or expired, they no longer hold any value. Therefore, storing them in the database isn’t necessary and would only add overhead in managing their lifecycle (i.e., creating, reading, and then deleting them after use or expiration).
  • Stateless Design: ASP.NET Identity often adopts a stateless approach for generating and validating tokens. This means the system can validate the token without referring to a stored copy. This is typically achieved through cryptographic methods, where the token contains all the necessary information for validation (like user ID, timestamp, and a cryptographic signature).
  • Simplicity and Performance: Not storing these tokens reduces the system’s complexity and improves performance. It avoids the need for additional database read/writes, which can be a performance bottleneck, especially in systems with a high volume of password reset requests.
How do you store and delete the Forgot Password Token in the AspNetUserTokens table?

Storing and deleting a “Forgot Password” token in the AspNetUserTokens table in ASP.NET Core Identity involves a slightly different approach compared to the basic handling of these tokens. Here’s how you can do it:

Storing the Token in AspNetUserTokens

First, we must generate the Password Reset Token using the GeneratePasswordResetTokenAsync(user) method of the UserManager<TUser> service.

You need to remember that ASP.NET Core Identity manages the AspNetUserTokens table automatically. However, if you want to store the token explicitly, you need to use the following method of the UserManager<TUser> service.

SetAuthenticationTokenAsync(user, loginProvider, tokenName, tokenValue)

Here, loginProvider and tokenName are strings that you can define. For example, loginProvider could be “PasswordReset” and tokenName could be “ResetToken”. tokenValue is the token generated in the previous step.

In our example, the SendForgotPasswordEmail private method generates the token. So, modify the SendForgotPasswordEmail method of the Account Controller as follows:

private async Task SendForgotPasswordEmail(string? email, ApplicationUser? user)
{
    // Generate the reset password token
    var token = await userManager.GeneratePasswordResetTokenAsync(user);

    //save the token into the AspNetUserTokens database table
    await userManager.SetAuthenticationTokenAsync(user, "ResetPassword", "ResetPasswordToken", token);

    // Build the password reset link which must include the Callback URL
    // Build the password reset link
    var passwordResetLink = Url.Action("ResetPassword", "Account",
            new { Email = email, Token = token }, protocol: HttpContext.Request.Scheme);

    //Send the Confirmation Email to the User Email Id
    await emailSender.SendEmailAsync(email, "Reset Your Password", $"Please reset your password by <a href='{HtmlEncoder.Default.Encode(passwordResetLink)}'>clicking here</a>.", true);
}
Deleting the Token from AspNetUserTokens

After the token is used or expires, you might want to remove it from the AspNetUserTokens table. When the user resets their password using the token, you should remove it from the database. You need to use the RemoveAuthenticationTokenAsync(user, loginProvider, tokenName) of the UserManager<TUser> service to remove the token from the AspNetUserTokens table. The loginProvider and tokenName should match what you used when storing the token.

In our example, the ResetPassword Post action method is used to reset the user password. So, once the password is reset successfully, we need to delete the token from the AspNetUserTokens database table. So, modify the ResetPassword Post action method of the Account Controller as follows:

[HttpPost]
[AllowAnonymous]
public async Task<IActionResult> ResetPassword(ResetPasswordViewModel model)
{
    if (ModelState.IsValid)
    {
        // Find the user by email
        var user = await userManager.FindByEmailAsync(model.Email);

        if (user != null)
        {
            // reset the user password
            var result = await userManager.ResetPasswordAsync(user, model.Token, model.Password);

            if (result.Succeeded)
            {
                //Once the Password is Reset, remove the token from the database
                await userManager.RemoveAuthenticationTokenAsync(user, "ResetPassword", "ResetPasswordToken");
                return RedirectToAction("ResetPasswordConfirmation", "Account");
            }

            // Display validation errors. For example, password reset token already
            // used to change the password or password complexity rules not met
            foreach (var error in result.Errors)
            {
                ModelState.AddModelError("", error.Description);
            }
            return View(model);
        }

        // To avoid account enumeration and brute force attacks, don't
        // reveal that the user does not exist
        return RedirectToAction("ResetPasswordConfirmation", "Account");
    }
    // Display validation errors if model state is not valid
    return View(model);
}

With the above changes in place, run the application, go to the Login page, and click on the Forgot Password link, as shown in the below image.

How do you store and delete the Forgot Password Token in the AspNetUserTokens table?

From the next screen, enter Email and click the Submit button, as shown in the image below.

How To Store Tokens in ASP.NET Core Identity

Once the User Enter the Email address and clicks on the Submit button, an email is sent to the above Email ID. At the same time, it should have entered the AspNetUserTokens table, as shown in the image below.

Why are the Generate Password Reset Tokens not stored in the AspNetUserTokens Table?

The user will receive the Password Reset Email in his email address, like the one below.

How To Store Tokens in ASP.NET Core Identity

Once the user clicks on the above link, it will open the following Password Reset page. The user needs to enter the Password, Confirm Password, and click on the Reset button, as shown in the image below.

Why are the Generate Password Reset Tokens not stored in the AspNetUserTokens Table?

Once the user provides the Password and Confirm Password and clicks the Reset button, the password will reset, and you will get the following message.

How do you store and delete the Forgot Password Token in the AspNetUserTokens table?

Once the password is reset successfully, if you verify the AspNetUserTokens table, you will see the record should be deleted, as shown in the image below.

How To Store Tokens in ASP.NET Core Identity

Note: It is an assignment for you guys to Save and Delete the Confirmation Email Token from the AspNetUserTokens table. The most important point you need to remember is not to store these tokens in the database for security reasons. Only for testing purposes, you can do this.

How to Set Token Lifetime in ASP.NET Core Identity?

By default, the token lifetime is 24 hours or 1 day. But if you want, you can change this default time period. To set the token lifetime in ASP.NET Core Identity, we need to use the TokenOptions class. This class provides various properties we can configure to specify the lifespan of different types of tokens used in the identity system, such as email confirmation tokens, password reset tokens, etc. ASP.NET Core, we need to configure Token lifetime in the Program class as follows:

// Configure token lifespan
builder.Services.Configure<DataProtectionTokenProviderOptions>(options =>
{
    // Set token lifespan to 2 hours
    options.TokenLifespan = TimeSpan.FromHours(2);
});

Note: If you are using a custom token provider, you should configure its options in a similar manner, replacing DataProtectionTokenProviderOptions with the options class for your custom provider.

Token Providers in ASP.NET Core Identity

Token providers in ASP.NET Core Identity are components responsible for generating and validating tokens, typically used in scenarios like email confirmation, password resets, and two-factor authentication (2FA). These tokens are usually short-lived and act as a security measure to ensure the request is valid and comes from the expected user.

Here’s a brief overview of some common token providers in ASP.NET Core Identity:

  • Data Protection Token Provider: This is the default token provider for generating tokens for email confirmation, password resets, and other identity-related operations. It uses the ASP.NET Core’s Data Protection system to encrypt and decrypt tokens.
  • Email Confirmation Token Provider: Specifically used for generating tokens for email confirmation. It’s usually a specialized instance of the Data Protection Token Provider configured for email confirmation purposes.
  • Password Reset Token Provider: Similar to the Email Confirmation Token Provider, this is tailored for generating tokens for password reset operations. It ensures that the tokens are valid only for a short period.
  • Two-Factor Authentication (2FA) Token Provider: This provider generates tokens used in 2FA processes. These tokens are often time-sensitive and are used in conjunction with a second factor like an email, phone number, or authenticator app.
  • Custom Token Providers: Developers can create custom token providers by implementing the IUserTokenProvider interface. This allows for extending the token generation and validation logic to suit specific needs not covered by the default providers.
Token Creation in ASP.NET Core Identity:

ASP.NET Core Identity generates a password reset token for the user. This token is created using a secure data protection mechanism provided by the IDataProtector interface. It involves several elements:

  • User Identifier: To ensure the token is user-specific.
  • Timestamp: To enforce token expiration.
  • Security Stamp: A unique value stored in the user’s record that changes whenever security-related information (like password or email) changes.
  • Purpose String: A specific purpose string like “PasswordReset” to distinguish the token’s intent.
Token Validation in ASP.NET Core Identity:

ASP.NET Core Identity validates the token using the UserManager class. This validation checks:

  • If the token matches the user identifier.
  • If it’s not expired (based on the timestamp).
  • If the user’s security stamp has not changed since the token was issued.

If the token is valid, the user is allowed to reset their password. If not, an error is shown, and the process may need to be restarted.

Security Considerations
  • Encryption and Security: The data protection system in ASP.NET Core Identity encrypts and securely hashes the tokens, making them hard to tamper with.
  • Expiration: Tokens are time-limited, usually expiring in a short time frame (like 24 hours), to reduce the window of opportunity for misuse.
  • One-Time Use: Ideally, once a token is used or expired, it should be considered invalid.

In the next article, I will discuss Change Password in ASP.NET Core Identity. In this article, I explain How to Store Tokens in ASP.NET Core Identity. I hope you enjoy this article, How to Store Tokens in ASP.NET Core Identity.

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