SSH Command Authenticator
authprogs is an SSH command authenticator. It is invoked on an ssh server and decides if the command requested by the ssh client should be run or rejected based on logic in the authprogs configuration file.
Passwordless SSH using ssh identies or pubkeys can enable all sorts of wonderful automation, for example running unattended batch jobs, slurping down backups, or pushing out code. Unfortunately a key, once trusted, is allowed by default to run anything on that system, not just the small set of commands you actually need. If the key is compromised, you are at risk of a security breach. This could be catastrophic, for example if the access is to the root account.
Authprogs is run on the SSH server and compares the requested command against the authprogs configuration file/files. This enables authprogs to make intelligent decisions based on things such as the command itself, the SSH key that was used, the client IP, and such.
authprogs is enabled by using the command= option in the authorized_keys file.