Online JWT Decoder

A JSON Web Token (JWT) is a compact and URL-safe format for securely transferring claims between two parties. The claims in a JWT are encoded as a JSON object, which serves as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure. This enables the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and encrypted. JWTs are commonly utilized for authentication and authorization purposes, ensuring the secure transmission of information between parties.

JWT（JSON Web Token）通常包含三个部分：

• - 标头：这通常由两部分组成：令牌类型（即JWT）和正在使用的签名算法，如HMAC SHA256或RSA。
• - Payload: This contains the claims. Claims are statements about an entity (typically, the user) and additional data. There are three types of claims: registered, public, and private claims. Registered claims include predefined claims such as iss (issuer), exp (expiration time), sub (subject), and aud (audience). Public claims can be defined at will by those using JWTs. Private claims are custom claims created to share information between parties that agree on using them.
• - Signature: To create the signature part, you have to take the encoded header, the encoded payload, a secret, the algorithm specified in the header, and sign that. The signature is used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way.

The JWT Decoder is a convenient online tool for decoding and verifying JSON Web Tokens. Simply paste a JWT into the input field, and the tool will decode the header and payload, displaying their contents as JSON objects. This tool is helpful for understanding the structure, claims, and signature of JWTs, which is crucial for secure authentication and authorization in web applications.

JSON Web Tokens (JWTs) are frequently utilized for authentication and authorization in web applications. They serve as access tokens, enabling a user to access particular resources on a server following successful authentication. Moreover, JWTs can facilitate single sign-on (SSO) processes, allowing a user to log in to multiple services with a single authentication event. Additionally, JWTs can securely transmit information between two parties, guaranteeing the integrity and authenticity of the data.

在使用 JWT 时，确保其安全处理和存储至关重要。需要记住的一些安全考虑包括：

• - 始终使用HTTPS传输JWT以防止窃听和中间人攻击。
• - 在客户端安全存储JWT，例如存储在HttpOnly cookie中，以防止跨站脚本（XSS）攻击。
• - 实施适当的令牌过期和撤销机制以防止未经授权的访问。
• - 使用强大的签名算法，如RS256（RSA与SHA-256），以防止伪造。
• - 验证JWT负载中的所有声明以确保其正确性和真实性。