ASP.NET Web API Role-Based and Policy-Based Authorization

Introduction: ASP.NET Web API is a powerful framework designed for building RESTful web services. Security is a critical aspect of any application, and ensuring that only authorized users can access certain resources is essential. In ASP.NET Web API, authorization can be achieved through different mechanisms, such as role-based and policy-based authorization. These mechanisms provide flexible and granular ways to control access to resources.

1. Role-Based Authorization:

Role-based authorization is a common approach to controlling access based on the user's role within an organization. In this model, permissions are grouped into roles, and users are assigned to these roles.

How It Works:

• User Assignment: When a user logs into the application, they are assigned specific roles.
• Role Authorization: Controllers or actions can be decorated with [Authorize(Roles = "RoleName")] attribute to restrict access to users who belong to the specified role.

Example:

[Authorize(Roles = "Admin, Manager")]
public class OrdersController : ApiController
{
    public IEnumerable<Order> Get()
    {
        // Only users in the Admin or Manager role can call this action
        return new List<Order>();
    }
}

Advantages:

• Simplicity: Easily understand and implement.
• Scalability: Roles can be scaled across multiple users efficiently.

Disadvantages:

• Static: Changes in role permissions can be cumbersome and require changes to the code or configuration.
• Limited Flexibility: Not suitable for complex authorization logic.

2. Policy-Based Authorization:

Policy-based authorization provides a more flexible and granular approach to access control. Unlike role-based authorization, policies can be defined based on complex logic and custom requirements.

How It Works:

• Define Policies: Create policies in the Startup class using the services.AddAuthorization() method.
• Apply Policies: Decorate controllers or actions with [Authorize(Policy = "PolicyName")] to apply the policy.

Creating Policies:

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthorization(options =>
    {
        options.AddPolicy("CanEditOrders",
            policy => policy.RequireClaim("Permission", "EditOrders"));
        options.AddPolicy("ManageUsers",
            policy => policy.RequireRole("Admin").RequireClaim("Department", "HR"));
    });
}

Applying Policies:

[Authorize(Policy = "CanEditOrders")]
public class OrdersController : ApiController
{
    public IHttpActionResult Put(int id, [FromBody] Order order)
    {
        // Only users with the EditOrders claim can call this action
        return Ok(order);
    }
}

Advantages:

• Flexibility: Policies can be defined based on any custom logic.
• Scalability: Policies can scale across multiple resources and users efficiently.
• Modular: Policies can be easily updated and managed.

Disadvantages:

• Complexity: More complex to implement and manage compared to role-based authorization.
• Configuration Overhead: Policies require additional configuration and maintenance.

Combining Role-Based and Policy-Based Authorization:

Role-based and policy-based authorization can be combined to create a more robust security model. For instance, you can use role-based authorization for basic access control and policy-based authorization for more granular and complex logic.

Example:

[Authorize(Roles = "Admin", Policy = "CanEditOrders")]
public class OrdersController : ApiController
{
    [HttpGet]
    public IEnumerable<Order> Get()
    {
        // Only users in the Admin role with the EditOrders claim can call this action
        return new List<Order>();
    }
}

3. Key Points:

• Role-Based Authorization: Best suited for simple and static role requirements.
• Policy-Based Authorization: Ideal for more flexible and complex scenarios with custom logic.
• Combining Both: Provides a comprehensive and scalable security model.

Conclusion: ASP.NET Web API offers robust mechanisms for securing web services through role-based and policy-based authorization. Role-based authorization is simple and easy to implement, making it suitable for straightforward scenarios. Policy-based authorization, on the other hand, offers flexibility and scalability for complex requirements. By understanding and leveraging these mechanisms, developers can create secure and efficient web APIs that meet their application's specific needs.

Certainly! Below is a comprehensive guide that will walk you through setting up and running an ASP.NET Web API application with Role-Based and Policy-Based Authorization, along with an explanation of the data flow. This guide will be suitable for beginners.

Step 1: Setting Up the ASP.NET Web API Project

Step 1.1: Create a New Project

1. Open Visual Studio.
2. Go to File > New > Project.
3. Select the ASP.NET Core Web Application template.
4. Give your project a name and click Create.
5. Choose the API template, and set the Framework to the latest .NET version (e.g., .NET 6.0 or .NET 7.0).
6. Ensure Enable Docker Support is unchecked unless you plan to use Docker.
7. Click Create.

Step 1.2: Add Authentication and Authorization

1. Open the Program.cs file.
2. Add authentication and authorization services:

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

// Configure Authentication and Authorization
builder.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options =>
{
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true,
        ValidIssuer = builder.Configuration["Jwt:Issuer"],
        ValidAudience = builder.Configuration["Jwt:Audience"],
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(builder.Configuration["Jwt:Key"]))
    };
});

builder.Services.AddAuthorization();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthentication(); // Use Authentication
app.UseAuthorization(); // Use Authorization

app.MapControllers();

app.Run();

3. Add the JWT settings in appsettings.json:

{
  "Jwt": {
    "Key": "your-very-very-secret-token-which-shouldnt-be-shared", // Use a strong key in production
    "Issuer": "yourdomain.com",
    "Audience": "yourdomain.com"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Step 2: Create the User Model and Dummy Data

1. Create a Models folder in the project.
2. Add a User.cs file inside the Models folder:

namespace YourProjectName.Models
{
    public class User
    {
        public int Id { get; set; }
        public string Username { get; set; }
        public string Password { get; set; }
        public string Role { get; set; }
    }
}

3. Create a DummyData.cs file inside the Models folder for storing some dummy data:

using System.Collections.Generic;

namespace YourProjectName.Models
{
    public static class DummyData
    {
        public static List<User> Users = new List<User>
        {
            new User { Id = 1, Username = "admin", Password = "password", Role = "Admin" },
            new User { Id = 2, Username = "user", Password = "password", Role = "User" }
        };
    }
}

Step 3: Create the Authentication Controller

1. Create a Controllers folder if it doesn’t already exist.
2. Add an AuthenticationController.cs file inside the Controllers folder:

using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using YourProjectName.Models;

namespace YourProjectName.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class AuthenticationController : ControllerBase
    {
        private readonly IConfiguration _configuration;

        public AuthenticationController(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        [HttpPost("login")]
        public IActionResult Login([FromBody] User loginModel)
        {
            var user = DummyData.Users.FirstOrDefault(u => u.Username == loginModel.Username && u.Password == loginModel.Password);

            if (user is not null)
            {
                var authClaims = new List<Claim>
                {
                    new Claim(ClaimTypes.Name, user.Username),
                    new Claim(ClaimTypes.Role, user.Role)
                };

                var authSigninKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration["Jwt:Key"]));

                var token = new JwtSecurityToken(
                    issuer: _configuration["Jwt:Issuer"],
                    audience: _configuration["Jwt:Audience"],
                    expires: DateTime.Now.AddMinutes(10), // Token will expire in 10 minutes
                    claims: authClaims,
                    signingCredentials: new SigningCredentials(authSigninKey, SecurityAlgorithms.HmacSha256)
                    );

                return Ok(new
                {
                    token = new JwtSecurityTokenHandler().WriteToken(token),
                    expiration = token.ValidTo
                });
            }
            return Unauthorized();
        }
    }
}

Note: This example uses in-memory dummy data for simplicity. For production, consider using a database.

Step 4: Role-Based Authorization

Step 4.1: Define Roles in the JWT Claim

In the Login method in the AuthenticationController, we already added the role claim.

Step 4.2: Create a Controller to Test Role-Based Authorization

1. Create an EmployeesController.cs file inside the Controllers folder:

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace YourProjectName.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class EmployeesController : ControllerBase
    {
        [HttpGet("{id}")]
        [Authorize(Roles = "Admin")] // Only Admins can access this endpoint
        public IActionResult GetEmployeeById(int id)
        {
            // This will retrieve and return employee details
            return Ok($"Details of employee with ID {id}");
        }

        [HttpPost]
        [Authorize(Roles = "Admin")] // Only Admins can access this endpoint
        public IActionResult CreateEmployee()
        {
            return Ok("Employee Created");
        }
    }
}

Step 5: Policy-Based Authorization

Step 5.1: Define a Custom Authorization Policy

1. Add the following code to the Program.cs file after configuring AddAuthentication:

builder.Services.AddAuthorization(options =>
{
    options.AddPolicy("MinimumRoleRequirement", policy =>
        policy.RequireRole(new[] { "Admin", "User", "Guest" }));

    options.AddPolicy("AdminOnlyPolicy", policy =>
        policy.RequireRole("Admin"));

    options.AddPolicy("AdvancedUserPolicy", policy =>
        policy.RequireRole("Admin", "User"));
});

Step 5.2: Create a Controller to Test Policy-Based Authorization

1. Create a RolesController.cs file inside the Controllers folder:

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace YourProjectName.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class RolesController : ControllerBase
    {
        [HttpGet("admin-only")]
        [Authorize(Policy = "AdminOnlyPolicy")] // Only Admins can access this endpoint
        public IActionResult AdminOnlyEndpoint()
        {
            return Ok("This is an admin-only policy-based endpoint");
        }

        [HttpGet("advanced-users")]
        [Authorize(Policy = "AdvancedUserPolicy")] // Only Admins and Users can access this endpoint
        public IActionResult AdvancedUsersEndpoint()
        {
            return Ok("This is an advanced users policy-based endpoint");
        }
    }
}

Step 6: Run the Application and Test the Endpoints

1. Press F5 to run the application.
2. The Swagger UI will pop up, which allows you to easily test the endpoints.
3. Use the POST /api/authentication/login endpoint to log in with one of the usernames and passwords from DummyData.cs.
4. Copy the token returned from the login endpoint.
5. For endpoints that require authorization, click on the "Authorize" button in the Swagger UI, paste the token, and then hit "Authorize."
6. Test the EmployeesController and RolesController endpoints to ensure they work as expected based on the roles and policies.

Data Flow Explanation

1. Client Request: A client makes a request to the /api/authentication/login endpoint with login credentials.
2. Authentication Controller: The Login action method checks the provided credentials against the dummy data.
3. Token Generation: If the credentials are valid, a JWT token is generated and returned to the client.
4. Client Storage: The client stores the token in memory or local storage.
5. Authorized Requests: When making requests to protected endpoints, the client includes the token in the Authorization header.
6. Authentication Middleware: The token is validated by the JwtBearer middleware.
7. Authorization Middleware: Based on the role claims in the token, the Authorization middleware decides whether the request is authorized.
8. Access Granted/Denied: If the request is authorized, the controller action method is invoked. If not, the client receives a 401 Unauthorized response.

This guide should provide a solid foundation for setting up and testing Role-Based and Policy-Based Authorization in an ASP.NET Web API application. Happy coding!

Top 10 Questions and Answers on ASP.NET Web API Role-Based and Policy-Based Authorization

1. What is the difference between Role-Based Authorization and Policy-Based Authorization in ASP.NET Web API?

Answer: Role-Based Authorization is a straightforward security model that restricts access to specific users based on their role within an organization. For example, only users with the "Admin" role can access certain endpoints. Policy-Based Authorization offers a more flexible approach by allowing the definition of policies that encapsulate business logic. Policies can be composed of multiple requirements, making it easier to enforce complex access rules. For instance, a policy might combine both role and claim-based checks to determine if a user can access a resource.

2. How do I implement Role-Based Authorization in ASP.NET Web API?

Answer: To implement Role-Based Authorization in ASP.NET Web API, follow these steps:

1. Configure Authentication Services:

   • Register authentication services in the Startup.cs file using services.AddAuthentication() and specify the default authentication scheme.

2. Configure Authorization Services:

   • Register authorization services using services.AddAuthorization() and specify the default policy if needed.

3. Assign Roles to Users:

   • When registering or assigning roles to users, store the roles in your user store database.

4. Use the [Authorize] Attribute:

   • Apply the [Authorize] attribute to controllers or actions to enforce role-based access. Example: [Authorize(Roles = "Admin, Manager")]

5. Check Roles in Your Business Logic:

   • Use the User.IsInRole("RoleName") method within your business logic to perform role checks.

Here's a sample snippet to illustrate how to implement Role-Based Authorization:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    })
    .AddJwtBearer(options =>
    {
        // JWT bearer configuration
    });

    services.AddAuthorization(options =>
    {
        options.DefaultPolicy = new AuthorizationPolicyBuilder(JwtBearerDefaults.AuthenticationScheme)
            .RequireAuthenticatedUser()
            .Build();
    });
}

3. How can I create and use a custom authorization policy in ASP.NET Web API?

Answer: Creating and using custom policies in ASP.NET Web API enhances the flexibility of access control by allowing you to define complex rules beyond simple roles.

1. Define Requirements:

   • Create a class that inherits from IAuthorizationRequirement to specify requirements that policies must meet.

2. Implement Authorization Handlers:

   • Implement authorization handlers by creating a class that inherits from AuthorizationHandler<TRequirement> where TRequirement is the requirement defined earlier.

3. Define Policies:

   • Use services.AddAuthorization() to register and define your policies within the ConfigureServices() method.

4. Apply Policies to Resources:

   • Use the [Authorize(Policy = "PolicyName")] attribute on controllers or actions to apply the policy.

Here's an example of creating and using a custom policy:

public class MustBeFromContosoRequirement : IAuthorizationRequirement { }

public class MustBeFromContosoHandler : AuthorizationHandler<MustBeFromContosoRequirement>
{
    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, MustBeFromContosoRequirement requirement)
    {
        if (context.User.HasClaim(c => c.Type == "domain" && c.Value == "contoso.com"))
        {
            context.Succeed(requirement);
        }

        return Task.CompletedTask;
    }
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddAuthorization(options =>
    {
        options.AddPolicy("ContosoOnly", policy =>
            policy.Requirements.Add(new MustBeFromContosoRequirement()));
    });

    services.AddSingleton<IAuthorizationHandler, MustBeFromContosoHandler>();
}

And in your controller:

[ApiController]
[Route("api/[controller]")]
[Authorize(Policy = "ContosoOnly")]
public class ValuesController : ControllerBase
{
    // Your actions here
}

4. Can I use both Role-Based and Policy-Based Authorization simultaneously in ASP.NET Web API?

Answer: Yes, you can use both Role-Based and Policy-Based Authorization simultaneously. This approach can be beneficial when you need a combination of simple role checks alongside more complex business logic.

In fact, role-based authorization is essentially a specialized form of policy-based authorization, where the policy is implicitly defined by the presence of a role claim.

Example:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddAuthorization(options =>
    {
        options.AddPolicy("AdminsAndContosoUsers", policy =>
            policy.RequireRole("Admin")
                  .AddRequirements(new MustBeFromContosoRequirement()));
    });

    services.AddSingleton<IAuthorizationHandler, MustBeFromContosoHandler>();
}

In this example, a policy named AdminsAndContosoUsers combines both role-based and custom policy-based authorization.

5. How can I handle dynamic or context-based authorization checks in ASP.NET Web API?

Answer: Handling dynamic or context-based authorization checks typically involves integrating with business logic or data storage that provides the necessary context. Here are a few ways to achieve this:

• Custom Authorization Handlers:

  • Extend AuthorizationHandler<TRequirement> to perform checks against dynamic contexts.

• Accessing Request Data:

  • Handlers can access data such as the HttpContext, request parameters, and other services through the AuthorizationHandlerContext.

• Database Queries:

  • Implement logic in authorization handlers that query the database to retrieve data necessary for making authorization decisions.

Here's an example using a custom handler that checks if a user can view a specific resource based on a context-sensitive rule:

public class ViewResourceRequirement : IAuthorizationRequirement
{
    public int ResourceId { get; }
    public ViewResourceRequirement(int resourceId)
    {
        ResourceId = resourceId;
    }
}

public class ViewResourceHandler : AuthorizationHandler<ViewResourceRequirement>
{
    private readonly IResourceService _resourceService;

    public ViewResourceHandler(IResourceService resourceService)
    {
        _resourceService = resourceService;
    }

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ViewResourceRequirement requirement)
    {
        var userId = int.Parse(context.User.FindFirstValue(ClaimTypes.NameIdentifier));
        if (_resourceService.UserCanViewResource(userId, requirement.ResourceId))
        {
            context.Succeed(requirement);
        }

        return Task.CompletedTask;
    }
}

// In ConfigureServices
services.AddScoped<ViewResourceHandler>();
services.AddAuthorization(options =>
{
    options.AddPolicy("CanViewResource", policy =>
        policy.Requirements.Add(new ViewResourceRequirement(123 /* resource ID */)));
});

6. How do I handle authorization failures in ASP.NET Web API?

Answer: Handling authorization failures is crucial for providing meaningful feedback to clients about why access was denied. Here's how you can handle authorization failures:

• Custom Error Responses:

  • Customize the error response by handling the AuthorizationFailed event in AuthorizationOptions.

• Exception Handling Middleware:

  • Use middleware to catch and process authorization failures to return custom error messages.

Here's an example of customizing the authorization failure response:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddAuthorization(options =>
    {
        options.FallbackPolicy = new AuthorizationPolicyBuilder()
            .RequireAuthenticatedUser()
            .Build();

        options.AuthorizationFailedFallbackPolicy = new AuthorizationPolicyBuilder()
            .RequireAssertion(context => false) // Always fail for demonstration purposes
            .Build();

        options.AuthorizationFailedFallbackPolicy.RequireAssertion(context =>
        {
            context.fail(new AuthorizationFailureReason("Failed authorization check"));
            return false;
        });
    });
}

7. Can I use Authorization Filters in ASP.NET Web API for Role-Based or Policy-Based Authorization?

Answer: Authorization Filters provide an alternative to the [Authorize] attribute. They can be used for both Role-Based and Policy-Based Authorization. Authorization filters are suitable when you need to inject logic before the execution of the action method or when you are working with action filters or result filters.

Example of using an authorization filter:

public class CustomAuthFilter : IAuthorizationFilter
{
    private readonly IAuthorizationService _authorizationService;

    public CustomAuthFilter(IAuthorizationService authorizationService)
    {
        _authorizationService = authorizationService;
    }

    public void OnAuthorization(AuthorizationFilterContext context)
    {
        if (!context.HttpContext.User.Identity.IsAuthenticated)
        {
            context.Result = new UnauthorizedResult();
            return;
        }

        var authorizeData = context.Filters
            .OfType<IAuthorizationFilterMetadata>()
            .SelectMany(af => af.Policy)
            .Distinct();

        var combinedPolicy = new AuthorizationPolicyBuilder()
            .RequireAuthenticatedUser();

        foreach (var policyName in authorizeData)
        {
            combinedPolicy.AddRequirements(_authorizationService.GetPolicy(policyName).Requirements);
        }

        var result = _authorizationService.AuthorizeAsync(context.HttpContext.User, combinedPolicy.Build()).Result;
        if (!result.Succeeded)
        {
            context.Result = new ForbidResult();
        }
    }
}

// Registration in Startup.cs
services.AddControllers(options =>
{
    options.Filters.Add(new CustomAuthFilter(authorizationService));
});

8. How can I unit test the authorization logic in ASP.NET Web API?

Answer: Unit testing authorization logic ensures that security rules are properly implemented and maintained over time. To unit test authorization logic, you can:

• Mocking Authorization Services:

  • Use mocking frameworks like Moq to create test doubles for IAuthorizationService and other dependencies.

• Creating Test Contexts:

  • Simulate different user contexts by configuring ClaimsPrincipal with different roles and claims.

• Testing Handlers:

  • Directly invoke authorization handlers to verify their behavior under various conditions.

Example of unit testing an authorization handler:

public class MustBeFromContosoHandlerTests
{
    [Fact]
    public async Task HandleRequirementAsync_WithContosoUser_Succeeds()
    {
        // Arrange
        var requirement = new MustBeFromContosoRequirement();
        var claims = new[] { new Claim("domain", "contoso.com") };
        var user = new ClaimsPrincipal(new ClaimsIdentity(claims));
        var context = new AuthorizationHandlerContext(new[] { requirement }, user, null);
        var handler = new MustBeFromContosoHandler();

        // Act
        await handler.HandleAsync(context);

        // Assert
        Assert.True(context.HasSucceeded);
    }
}

9. What are the best practices for implementing and maintaining authorization in ASP.NET Web API?

Answer: Following best practices ensures that your authorization implementation is secure, maintainable, and scalable. Here are some key best practices:

• Keep Policies and Handlers Organized:

  • Group related requirements and handlers in logical namespaces or folders.

• Avoid Hardcoding Roles:

  • Centralize role definitions and avoid hardcoding them throughout the application, which facilitates changes and maintenance.

• Leverage Middleware for Consistency:

  • Use middleware for global authorization checks to ensure consistent application security.

• Document and Audit Authorization Logic:

  • Maintain documentation for authorization policies and regularly audit the codebase to ensure security rules are not inadvertently bypassed.

• Test Authorization Logic Regularly:

  • Unit test authorization handlers, policies, and filters to catch potential issues early.

• Stay Updated with Security Practices:

  • Stay informed about the latest security practices and updates to libraries and framework version to minimize vulnerabilities.

10. How do I integrate external authorization services in ASP.NET Web API?

Answer: Integrating external authorization services can enhance security by leveraging external providers that manage user identity and access. Common external authorization services include Azure Active Directory, Auth0, and Okta.

1. Configure External Authentication Handlers:

   • Use AddAuthentication() to configure the external authentication handler for your chosen provider.

2. Set Up Client Credentials:

   • Provide client credentials such as application IDs and secrets to authenticate with the external provider.

3. Define Policies for External Users:

   • Create policies and handlers that understand how to interpret tokens and claims issued by the external provider.

4. Secure Token Storage:

   • Implement secure storage and handling of tokens received from external services to prevent theft or misuse.

Here's an example of integrating Azure Active Directory:

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(AzureADDefaults.BearerAuthenticationScheme)
        .AddAzureADBearer(options =>
        {
            Configuration.Bind("AzureAd", options);
        });

    services.AddAuthorization(options =>
    {
        options.AddPolicy("AzureAdPolicy", policy =>
            policy.RequireRole("Admin").RequireAuthenticatedUser());
    });
}

In your appsettings.json:

{
  "AzureAd": {
    "Instance": "https://login.microsoftonline.com/",
    "Domain": "yourdomain.onmicrosoft.com",
    "ClientId": "your-client-id"
  }
}

By following these steps, you can effectively integrate external authorization services to secure your ASP.NET Web API.

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These 10 questions cover a comprehensive range of topics related to Role-Based and Policy-Based Authorization in ASP.NET Web API, providing actionable insights and best practices for implementing and maintaining secure web services.