When it comes to developing a secure REST API, authentication is essential. Imagine your application as a party; authentication acts like the door that decides which guests can enter—or, more precisely, which requests are allowed in and out.
You want to make sure you can trust the identity of each request made so only authorized users have access to sensitive data or privileged operations. Luckily, various options exist for authenticating requests.
This blog post will explain four popular methods: API Keys, OAuth 2.0, HTTP Authentication Schemes, and JWT Authentication. Now let's dive into these technologies one by one to get our virtual “party” running securely.
API Authentication Overview
Before jumping into API authentication methods, let's look at the bigger picture. API authentication is based on two principles: authentication and authorization.
API Authentication vs. Authorization
Authentication is the process of verifying a user's identity. After that, we can move forward with API authorization —the process of granting API access to the authenticated user. While an API might verify your identity (authenticate), it may not grant you permission to make a certain request (authorize).
Now that you have an API authentication overview let's look at the four API authentication methods.
4 Secure API Authentication Methods
1. API Keys
API Keys are secret tokens used to authenticate API requests. They usually consist of a public key and a private key, and they help API providers identify the API consumer and grant them access to API resources. API Keys are generally sent as an HTTP header in API requests. API Keys are used for API authentication in a wide range of applications, from mobile apps to enterprise SaaS products.
How do API Keys work? API Keys are generated in API management systems and can be sent as a header/query parameter in API requests. The API provider validates the API keys for authentication before granting access to API resources.
Why use API keys? API Keys are fast and easy to use, and they provide flexibility. API providers can easily revoke API keys when needed, and API consumers can generate new API keys if the existing ones become compromised or outdated.
What are the disadvantages of API Keys? API Keys are great for API authentication but offer no inherent security. API providers need to take extra steps to ensure API requests are secure, such as API key rotation and API rate limiting.
2. OAuth 2.0
OAuth 2.0 is an authorization protocol that gives API users access to a service without sharing their passwords. It's often used for authentication in web, mobile, and desktop applications. OAuth 2.0 is based on the 'token' concept, which allows API users to show they are authenticated without sending the API their username and password every time they request.
How does OAuth 2.0 work? API consumers use authorization grants (e.g., code, password) to obtain access tokens. API providers use scopes to define API access permissions (e.g., read, write). API consumers can then use the tokens to access API resources corresponding to authorization grants and API scopes.
Why use OAuth 2.0? OAuth 2.0 is an industry-standard protocol for API authentication with many advantages, such as improved security, better user experience, and scalability. Additionally, API providers and API consumers do not need to share credentials to authenticate API requests using OAuth 2.0.
What are the disadvantages of OAuth 2.0? The main disadvantage of this API authentication method is its complexity; it requires multiple steps to grant API access securely and set up API authentication.
3. HTTP Authentication Schemes (Basic & Bearer)
Basic and Bearer authentication schemes are widely used API authentication methods. They both use HTTP headers to authenticate API users, and they can be used in combination with API Keys for added security.
HTTP Basic Authentication: API consumers send API requests with a username and password in an HTTP header. API providers then validate the credentials to authenticate API users. This simple API authentication method lacks security, as API requests can be intercepted easily.
HTTP Bearer Authentication: API consumers send API requests with a unique API access token in an HTTP header. API providers then validate the API access token to authenticate API users. This API authentication method is more secure than Basic, as API requests cannot be intercepted easily.
Why use HTTP authentication schemes? HTTP authentication schemes are fast and easy to implement, and they provide a higher level of security than API Keys. API providers can also enable API rate limiting to prevent malicious API requests.
What are the disadvantages of HTTP authentication schemes? The main disadvantage of this API authentication method is its complexity; it requires multiple steps to grant API access securely and set up API authentication. Additionally, API users need to store their credentials in a secure place.
4. JWT Authentication (JSON Web Token)
JSON Web Token (JWT) authentication is an API authentication method that uses tokens to authenticate API consumers. This API authentication method uses JSON data structures to store authentication information for API users, such as usernames and expiration dates.
How does JWT work? API consumers send API requests with a valid username and password to the API provider. The API provider then generates an encrypted token with the user's credentials, which is sent back to the consumer in response. API users can then use this token in subsequent API requests to authenticate themselves.
Why use JWT Authentication? JWT Authentication provides advanced security measures because tokens are cryptographically signed and encrypted, making them virtually impossible to intercept or decode. Additionally, JWT is a flexible API authentication method that can be used across multiple API requests and API providers.
What are the disadvantages of JWT Authentication? Storing API users' credentials in tokens can be risky, as they may become compromised if the API provider does not store them securely. Furthermore, tokens need to be refreshed periodically for additional security, which can be difficult to manage.
By understanding authentication and authorization concepts and the four API authentication methods outlined in this post, you can confidently develop a secure API against malicious requests. Plus, you can ensure your API guests get to your party safely.
How to select the right API Authentication Method?
Picking the right API authentication method depends upon your project requirements. API keys are suitable for simple API requests or where a high-security level is not needed, whereas OAuth 2.0 and JWT offer more out-of-the-box features for API authentication, such as token revocation and refresh tokens. Ultimately, weighing up each API authentication method to select the best solution for your API authentication needs is important.
Finally, API authentication is essential in keeping API requests secure and ensuring users get access to the data they need. By understanding API authentication concepts and the various API authentication methods available, you can confidently protect your API and keep API users safe.