JWTtodennus

JWTtodennus refers to authentication using JSON Web Tokens. A JSON Web Token is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs are commonly used in web applications to transmit user identity information between a client and a server.

The structure of a JWT is typically composed of three parts separated by dots: a header, a payload, and a signature. The header usually contains information about the type of token and the signing algorithm used. The payload contains the claims, which are statements about an entity (typically, the user) and additional data. The signature is used to verify that the sender of the JWT is who it says it is and to ensure that the message was not changed along the way.

When a user logs into an application, the server can generate a JWT containing user information and send it back to the client. The client then stores this token, typically in local storage or a cookie. On subsequent requests to protected resources, the client includes the JWT in the request header. The server can then verify the signature of the JWT. If the signature is valid, the server trusts the claims in the payload and grants access to the requested resource. This process eliminates the need for the server to repeatedly query a database for user authentication on every request, improving performance and scalability.