OAuth and API Security

Why Should Companies Bank on OAuth Frameworks to Fortify their API Servers?

Connectivity and convergence are what the quintessential technologies such as the Internet of Things (IoT) have fretted into this digital-driven world. It is indeed the power that drives future explorations, but at the same time, it puts at peril the authenticity, authority, and of course, privacy of enterprise data, services, and users.

Most often, we tend to use the same credentials to access many different websites and apps. And that is when, knowingly or unknowingly, we allow complete access to our contacts, social media accounts, messages, photographs, and more to third-parties. In short, we become susceptible to risks of connectivity and convergence. 

And this is exactly the problem, which OAuth (Open Authorization) resolves. Back in the year 2006-2007, researchers found that API (Application Programming Interface) lacked an open standard that could have allowed access to user’s information by third-parties, without revealing their passwords and with limitations. OAuth was developed to boost the security of API servers. 

Let’s know more about the API and OAuth Framework and how the latter boosts the security of the former.  

APIs and the Need for Security

API, in simple terms, refers to a method or piece of code written in any technology to establish communication between two or more software systems. While APIs help to unlock data from legacy systems, expose data and services to both internal and external partners, it is crucial that they are scalable, reliable, and most importantly secure.

It is obvious that the organizations should have a clear idea of what kind of data is being exchanged through APIs and anticipate in advance the APIs usage and status, prospective partners/clients, and the level of security required. With the ever-increasing cyber-attacks and security vulnerability discoveries such as SSL Poodle and more, poor design in the API security or insufficient planning could result in potential threats and attacks on the organization’s data and resources and may even cause monetary losses.

API Security deals with the authentication and authorization aspects of API. Authentication means determining the identity of the end-user and authorization means determining the eligibility of the end-user to access that specific data.
APIs can be secured using multiple security mechanisms such as Basic Authentication, Digestive Authentication, and more. However, each mechanism has its own limitations such as vulnerability for the Man-in-the-Middle attacks, implementation complexity, and limitations of compatibility across different software platforms. These limitations impediment businesses from achieving true scalability and load balancing capabilities.

OAuth Aids API Security
OAuth stands for Open Authorization. It is a token-based security mechanism, which secures API access delegation. Here’s a diagram depicting OAuth’s workflow.

Today, OAuth 2.0 is widely used by digital-born tech-giants such as Google, Twitter, and more to protect user’s data from being exploited by third-parties. It enables secured-delegated access to protect resources.
chartOAuth Framework uses tokens to addresses all issues by introducing an authorization layer and separating the role of the client from that of the resource owner.
So, what is a token?

The token is a unique secure string associated with each request from the client to the server that will authenticate and authorize the client against the server resource or service. Tokens support the key principle of being stateless and of the RESTful services (used to build lightweight and scalable web services)—just like the Basic Auth. It delegates authorization and defines the scope and the ability to expire or revoke.

Tokens are of two types:

  1. Bearer Token:

    Whoever possesses a valid bearer token will have access to the protected server resources (OAuth 2.0 follows the Bearer token approach). Bearer token does not require a bearer to prove possession of cryptographic material. It is created by the Authorization server. 

  2. HOK (Holder of Key) Token:

    Along with the validity of the token, it is also important to validate the client who holds the token. In the case of HOK token, it is not possible for any other party other than the legitimate party to use the token as they will not know the asymmetric key pair.

How does OAuth 2.0 Work?

OAuth enables a third-party application to obtain limited access to an HTTP service either on behalf of resource owners (by orchestrating an approving interaction between resource owners and the HTTP service) or by allowing the third-party applications to obtain access on their own behalf (Delegated Authorization). The resource owners do not have to share their credentials with the client.
OAuth defines the following roles and grant types, which are part of the OAuth authorization hand-shake and the different grant types are used for different purposes as indicated below:


  • Resource Owner: An entity capable of granting access to a protected resource. When a resource owner is a person, it is referred to as an end-user.
  • Resource Server: The server that hosts protected resources and is capable of accepting and responding to protected resource requests using access tokens.
  • Client: An application that makes protected resource requests on behalf of resource owners. The term "client" does not imply any particular implementation characteristics (i.e., the application can be executed on a server, a desktop, or on other devices as well).
  • Authorization Server: The server issuing access tokens to the client after successfully authenticating resource owners and obtaining authorization.


  • Authorization Code Grant is used for confidential clients such as server-based clients.
  • Implicit Grant is used for public clients such as browser-based clients.
  • Resource Owner Credentials Grant is used when the client has access to the resource owner’s credentials.
  • Client Credentials Grant is used when registered clients want to obtain a token for themselves.
  • Refresh Token Grant is used to refresh expired access tokens, releasing fresh ones.

In the case of bearer tokens, the OAuth tokens are usually meant to be short-lived for ensuring security and avoiding replay attacks. The refresh token is used for exchanging tokens for a new access token. Therefore, in case of unauthorized access to the API server by any third-party, the token will allow access only until the time it expires.
Tech-giants Bank on OAuth to Boost API Security, You Can Too

Frameworks such as OAuth play an imperative role in ensuring the security of data in a world that is predominantly driven by it. Tech-giants such as Amazon, Google and more have embraced the OAuth framework to build ramparts and moats to allow restricted access and deliver maximum security to the user’s data.

With its token system, OAuth—an open-source standard to data sharing—adds a multi-layer authentication process to the APIs, thus preventing the user’s data from being compromised.
At a time when digitization runs rife and evolving technologies force open the door of opportunities for businesses, security boosting frameworks such as OAuth can be a credibility determiner.