The following <key> names are defined:
+ - "accountname": the account name of a client (can't be empty)
+ - "certfp": the certificate fingerprint of a client (can't be empty)
+ - "cloakhost": the cloaked hostname of a client
- "host": the hostname of a client (can't be empty)
- "info": info text ("real name") of a client
- "user": the user name of a client (can't be empty)