Hello Seekers! In this blog, We will get an overview of PASETO – a secured alternative for JWT and how it solves the security issues of the widely used token based authentication, JWT.

Token Based Authentication

It is an authentication mechanism where the client will first make a request to the server for login, with a username and password. Server checks if the credentials are correct and sends back a response with a signed token. Servers uses a secret key stored on the server to create this signed token. This authentication mechanism is more popular in web and mobile application development.

JSON web token (JWT) is the most popular token-based authentication. However, many security threats have been exposed in recent years, causing people to migrate to other types of tokens.

Platform Agnostic Security Token or PASETO is one such token which is being accepted as the best secured alternative for JWT. 

PASETO vs JWT

JWT is a base64 string divided into three parts with dots. First part is the header while the second part is the payload data and the last part holds the digital signature. JWT uses weak signing algorithms and a poor implementation can make the whole system vulnerable. Also, it is easy to extract the signing algorithm from JWT’s header.

PASETO successfully addresses all these issues. PASETO provides a strong cipher suite with each version. This resolves the JWT’s weak algorithm issues. Moreover, users just need to choose a version of PASETO and the library will take care of the encryption. On top of that, PASETO also makes token forgery a lot more difficult and users will not be able retrieve any algorithm related data from the token headers.

PASETO Structure

Now, let’s take a look at the structure of the PASETO token. Each token has four parts, separated by dots. First part will hold the token version and the second part holds the purpose of the token. It can be either local or public.

If the token’s purpose is local, it means that PASETO is using a symmetric-key digital signature algorithm to sign the token while it is an asymmetric-key algorithm in public’s case. Now, the third part of the token is the encrypted payload. Finally, the fourth part of the token is the token footer. It is an optional part of the token which we can use to share unencrypted base64 encoded public data.

If we decrypt the encrypted payload part of the token, we will find three sub parts in the payload. First is the payload body which stores data and expiration time. Second sub part is the nonce value. The nonce value is useful in authentication and encryption processes. Final sub part of the payload is the authentication tag, used for authenticating the message.

Everything in the PASETO token is authenticated with the AEAD algorithm. Hence, it is not possible to tamper with the token without the server’s secret key. This token implementation is not just safer but is also easier than the JWT.

PASETO is more secure than JWT and offers a simpler implementation. As a result, many developer communities started accepting it as a better alternative to JWT. Now that you too know the advantages of using PASETO over JWT, what are you going to use for your next project ? Choose wisely. Have a great day.