Running the agent --debug 4096 --debug-level guru --daemon --min-passphrase-len 0
$ ssh my-vm gpg-agent[29336]: ssh handler 0x------------ for fd 8 started gpg-agent[29336]: ssh request handler for request_identities (11) started gpg-agent[29336]: ssh request handler for request_identities (11) ready gpg-agent[29336]: ssh request handler for sign_request (13) started gpg-agent[29336]: DBG: agent_get_cache '4B9XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXA' (mode 4) ... gpg-agent[29336]: DBG: ... miss gpg-agent[29336]: starting a new PIN Entry gpg-agent[29336]: DBG: connection to PIN entry established ** Message: Remote error from secret service: org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.secrets was not provided by any .service files Failed to lookup password for key s/4B9XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXA with secret service: The name org.freedesktop.secrets was not provided by any .service files #### here ssh key PINentry popup => just enter (no passphrase) #### gpg-agent[29336]: DBG: error calling pinentry: No passphrase given <GPG Agent> gpg-agent[29336]: failed to unprotect the secret key: No passphrase given gpg-agent[29336]: failed to read the secret key I guess there may be something "special" against passphrase-less ssh keys, but couldn't find any documentation/hints about this.
