# Appendix F: Hidden service directory format [HIDSERVDIR-FORMAT] This appendix section specifies the contents of the HiddenServiceDir directory: - "hostname" [FILE] This file contains the onion address of the onion service. - "private_key_ed25519" [FILE] This file contains the private master ed25519 key of the onion service. [TODO: Offline keys] ```text - "./authorized_clients/" [DIRECTORY] "./authorized_clients/alice.auth" [FILE] "./authorized_clients/bob.auth" [FILE] "./authorized_clients/charlie.auth" [FILE] ``` If client authorization is enabled, this directory MUST contain a ".auth" file for each authorized client. Each such file contains the public key of the respective client. The files are transmitted to the service operator by the client. See section [CLIENT-AUTH-MGMT] for more details and the format of the client file. (NOTE: client authorization is implemented as of 0.3.5.1-alpha.)