The SSH agent unlocks your key once and signs for you so the key never leaves memory. ssh-add, where it lives on each OS, and why the socket needs guarding. Originally published at termal.in . If you've protected your SSH key with a passphrase — and you should have — you've met the annoyance the agent exists to solve: type that passphrase for every single connection, or leave the key unprotected. The SSH agent is the third option. Unlock the key once , and the agent handles every auth...