To prevent the substitution of important parameters in ONLYOFFICE Document Server requests an encrypted signature is added to it in the form of token.
The token is added in the configuration when initializing Document Editor and during the exchange of commands between document storage service and document editing service, document command service, document conversion service and document builder service.
The token is generated using the JWT (JSON Web Tokens) standard. The tokens are signed by the server's key, so the client is able to verify that the token is legitimate.
JSON Web Tokens consist of three parts separated by dots (.), which are: header, payload, signature. The header consists of two parts: the type of the token (JWT), and the hashing algorithm (HMAC SHA256). The second part of the token is the payload, which contains the claims in JSON format. 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.
ONLYOFFICE Document Server validates the token. The data from the payload is considered valid and is used instead of the corresponding data from the main parameters. If the token is invalid, the command is not executed.
See the Signature configuration section to find more.