What is API key authentication in .NET Core Web API?

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Aryan Kumar · Answer

API key authentication is a type of authentication that uses a secret key to authorize access to an API. The secret key is typically sent in the header of the HTTP request.

In a .NET Core web API, API key authentication can be implemented using the ApiKeyMiddleware class. The ApiKeyMiddleware class allows you to customize the following aspects of API key authentication:

The header that the API key is sent in.
The format of the API key.
The way that the API key is validated.
The way that unauthorized requests are handled.

To use the ApiKeyMiddleware class, you need to add it to the middleware pipeline in your application. You can do this by adding the following code to your Startup class:

C#

app.UseMiddleware<ApiKeyMiddleware>();

You can then customize the behavior of the ApiKeyMiddleware class by setting the appropriate properties. For example, to change the header that the API key is sent in, you can set the HeaderName property.

The following code shows how to change the header that the API key is sent in:

C#

app.UseMiddleware<ApiKeyMiddleware>(
    options => options.HeaderName = "X-Api-Key");

You can also customize the format of the API key by setting the KeyFormat property. The KeyFormat property can be set to one of the following values:

PlainText: The API key is sent in plain text.
Hashed: The API key is hashed before it is sent.
Encrypted: The API key is encrypted before it is sent.

The following code shows how to change the format of the API key:

C#

app.UseMiddleware<ApiKeyMiddleware>(
    options => options.KeyFormat = ApiKeyFormat.Hashed);

Finally, you can customize the way that unauthorized requests are handled by setting the OnUnauthorized property. The OnUnauthorized property can be set to a delegate that will be called when an unauthorized request is received.

The following code shows how to change the way that unauthorized requests are handled:

C#

app.UseMiddleware<ApiKeyMiddleware>(
    options => options.OnUnauthorized =
        (context, exception) => context.Response.StatusCode = 401);

By customizing the behavior of the ApiKeyMiddleware class, you can tailor API key authentication to the specific needs of your application.

Here are some additional considerations when using API key authentication in a .NET Core web API:

The header that the API key is sent in: The header that the API key is sent in should be a header that is not commonly used by other applications.
The format of the API key: The format of the API key should be secure and difficult to guess.
The way that the API key is validated: The API key should be validated against a secure store.
The way that unauthorized requests are handled: Unauthorized requests should be handled in a way that does not compromise the security of the application.

By following these considerations, you can ensure that API key authentication is secure and effective.

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What is API key authentication in .NET Core Web API?

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