What is a token?

A token is a small piece of data representing an object or a right, without revealing its internal structure or content. In the context of information technology, tokens are used for various purposes, such as:

• Authentication and authorization: A token is issued to a user after successful authentication and serves to confirm their identity and access rights to resources. Examples include JWT (JSON Web Token), OAuth tokens.

  {
    "sub": "1234567890", // subject (user identifier)
    "name": "John Doe", // user's name
    "iat": 1516239022 // issued at (token issuance time)
  }
  

• Cryptography: A token can represent a cryptographic value used to confirm data integrity or authenticity.

• Data tokenization: Replacing sensitive data (e.g., credit card number) with non-sensitive equivalents (tokens). This enhances security, as leaked tokens do not reveal real data.

• Blockchain: A digital asset representing some value or ownership right.

Token type	Main purpose	Example of use
Authentication token	Confirming user authenticity	API access, web applications
Authorization token	Granting access rights to resources	Access to specific functions or data
Data token	Replacing confidential information	Payment processing
Blockchain token	Representing a digital asset or ownership right	Cryptocurrencies, governance tokens

Thus, a token is a universal mechanism for representing entities or rights in a compact and secure form.