The Different Token Types and Formats Explained

The Different Token Types and Formats Explained
The Different Token Types and Formats Explained

Authentication tokens are like the digital version of a ticket to an event. The user holding the token is allowed access to a website or account until they log out or until the session expires.

Tokens securely transmit user identity information between applications, websites and APIs to allow access to them. They also allow for scalable, secure and flexible access management across systems, networks and accounts.

Different token types are used are verify user identity based on usage, environment and account type. Read on to learn more about the types of authentication tokens.

Types Of Authentication Tokens

Token-based authentication types can either be hardware or software-based and the token type used in a given scenario is often assumed rather than outlined. This simply means different types of authentication tokens are used based on different scenarios.

Token Types

  • Hardware Tokens

Hardware tokens are physical tools that store authentication credentials for a user’s verification and identification.

If the token is a USB, then it needs to be inserted into the computer. This USB will require the user to enter a safety code or PIN to generate an OTP. This OTP will then authenticate your identity and authorise you to access the device.

Since these tokens demand possession as a primary need, they are capable of resisting various cyber threats like phishing attacks.

This is one of the reasons why these hardware tokens are usually utilised by giant corporation networks or government agency systems, as they maintain a high security standard.

Contactless, disconnected, and connected tokens come under this category of token types as well.

  • Access or API Tokens

Access tokens are the most common token type. These tokens bypass the traditional username-password credential system and provide credentials that enable a secure exchange of information.

Usually, authentication processes generate API tokens, and their format depends on the authentication protocol that is used by the system or network.

The system can transmit API tokens in HTTP headers, request bodies, or query parameters according to the API authentication mechanism used by the network.

Their lifetime is usually quite short to maintain security, however, if an attacker gains access to them they can gain access to the user account to which it was issued.

  • Refresh Tokens

The authorisation server provides refresh tokens to provide new access tokens to the users in order to authenticate and identify them. Once the old access token expires, the server generates a new key in the form of a refresh token.

These refresh tokens look like a random string of numbers or alphabets in a system-generated order that you need to enter in the system to produce an access token.

So, we can define refresh tokens as a mode of renewal for the actual password the authorisation server will generate for the user authentication.

  • ID Tokens

As the name suggests, the ID tokens signify the user’s identity information utilised to authorise access. This identity information is encrypted in the ID token by the authorisation server that is used as an identifier by the server.

The ID tokens contain information like standard properties, who issued the token, what happens to it when it expires and all the other authenticated user data.

  • Bearer Tokens

Bearer tokens are just access tokens that the user utilises to access authorised resources without needing further user identification. So, the bearer of the access token will be granted access to authorised departments of the network or application.

This cannot be deemed as the best or the safest type of token since there is no guarantee that the bearer of the access token is the one performing further activities. In cases of network hijack, a bearer token can prove to be very insecure.

  • Sender Constrained Tokens

The authorisation server creates a constrained relation between the token and the application using cryptographic keys. When the user issues the token, the server uses cryptographic keys to bind the token and the application or network.

Since the token is constrained to the sender, it is named a sender-constrained token. These sender-constrained tokens are usually very safe since the authorisation information is in cryptographic format and is only known to the server.

Token Formats

  • Opaque Tokens

Opaque means something that is not see-through. So, we can say that all the types of opaque tokens are not transparent. The reason behind this is that this format of tokens is presented in the form of unique yet random strings of alphabets of numbers.

The format of the tokens is the reason why these tokens do not convey any user information to the application or the API. There is no way for the application to accidentally or intentionally leak the user’s information.

  • JSON Web Token (JWT)

JWTs are simple and compact yet versatile tokens for the secure exchange of information. JWTs use JSON objects in order to transfer and exchange data.

These tokens are generally used for authenticating and authorising where they identify the user, handle permissions, and store expiration times of the sessions.

There are three parts of a JWT and those are header, payload, and signature.

  • Header - The header specifies the type of the token sent to the user,
  • Payload - The payload contains the abovementioned data and claims, and
  • Signature - The signature keeps the integrity of that token.

These are highly efficient and self-contained and, hence, are widely used in web applications and single sign-on networks.

Token-Based Authentication Types – The Best Of Both Worlds

Token-based Authentication in itself is an optimal mode to authenticate a user’s identity in order to authorise access for them. However, a collaboration of two different kinds of tokens can maximise the benefits they provide. Let’s look at some of these combinations!

Phantom tokens

Phantom tokens combine the benefits of two token formats: opaque tokens as well as the JWT with public applications. The API gateway exchanges the opaque token into JWT for higher-level consumption, i.e., the upstream API. This helps prevent the user’s information from getting to the application, but it reaches the API for authentication.

Split tokens

With split tokens, we get to experience the flexibility of JWTs and the confidentiality of opaque tokens’ cryptographic nature, both alike. Like phantom tokens, these split tokens allow the server to access session information without leaking any information or user authentication data to the public client.

Token handler

Secure Password Authentication (SPA) is a protocol that is supposed to protect passwords while authenticating user identity. However, due to the stringency in browser cookie policies, it has become difficult to secure tokens, even with SPAs.

This is where a token handler enters the conversation. While it is not a token type, a token handler enables security in the entire process of forwarding the cookie to SPA (that is converted into a token by the token handler) and the token to the API.

Benefits of Token-Based Authentication

Enhanced Security

Tokens provide robust security while authenticating the user’s identity. Unlike traditional forms of authentication, token-based authentication systems mitigate and minimise risks of exposing sensitive credentials.

Tokens are also short-lived since they are time-based. This reduces the window of opportunity for attackers to breach and misuse data while in exchange.

Flexible and Versatile

The different types of authentication tokens provide versatile solutions for different authorisation scenarios. They are suitable for various tools like web applications, single sign-on networks, access, control, API security, etc.

This also displays the flexibility of these portable units. Not only that, but they also possess interoperability. This feature ensures that these tokens can be easily exchanged, fostering compatibility, flexibility and versatility.


Scalability is an essential and non-negotiable feature for any digital tool since one expects the network to grow and expand. Token authentication provides scalability for networks, particularly in environments with high transaction volumes.

In systems where multiple services need to interact securely, token authentication enables seamless communication without the need for continual or constant synchronisation with the central authentication server.

Improved Performance

With easy-to-perform and all-inclusive solutions for authentication, token authentication offers a seamless authorisation experience for its users. This improved and top-notch performance usually enhances the user experience.

Token types also eliminate the need to store session data because all the necessary information is encapsulated within the token. This reduces the complexity and required time and increases the ability to perform better.

Drawbacks Of Token-Based Authentication

Token Management Overhead

There are a lot of management duties that follow the implementation of Token Authentication.

It comes with tasks like token management distribution, including their generations, expiration, and revocation. This can be a lot of administrative overhead in order to handle the token lifecycle.

Token Theft Risk

Token security can be a big issue after implementing token-based authentication. Since these portable units are temporary credentials or PINs, they are susceptible to theft or at least interception.

Unauthorised access to the token types can lead to attackers impersonating the authorised user. To avoid this, other layers of security must be added.

Resource Consumption

The token authentication system can also consume additional network resources, such as CPU, memory, storage and bandwidth, during token validation and cryptographic transactions.

This impacts the system’s performance and its ability to scale according to the requirements.

Token Replay Attacks

This is when the attacker intervenes and reuses the valid token provided by the system for authentication to get unauthorised access. Hence, the implementation of various measures like token expiration is essential.

Ending Notes

We can end our blog by saying that the token authentication landscape consists of numerous compact, simple, complex, and secure modes for authentication in the form of tokens.

Considering the benefits of each token-based authentication type, we can say that they are valuable digital solutions for securing your system.

Navigating the different types of authentication tokens can be overwhelming, but token-based authentication that supports Multi-Factor Authentication is always a good option!

You can find several other security solutions at Instasafe,  in addition to MFA, like zero-trust network access (ZTNA).

Frequently Asked Questions (FAQs)

  1. What is token-based authentication?

Token Based Authentication is the process of authenticating a user’s identity to authorise access using portable units called tokens. These tokens can come in various types and they mitigate the need for sole reliance on static APIs like passwords.

2. What should one consider before implementing a token-based authentication procedure?

Before implementing token-based authentication, one should carefully consider all the determining and influencing factors. Some factors that can influence the decision are token security, transmission over secure channels, and expiration policies.

3. In the age of software-based authentication, are hardware tokens still relevant?

Yes! Hardware tokens remain relevant due to their security-intensive qualities. It is highly recommended in places with high standards for security since possession is the primary need of this token type.