Seahorse Password and Keys
Seahorse is the GNOME (and Cinnamon) keyring, which managers passwords and SSH keys.
It will load your private keys into memory, protected by a password which is the same password you use to log in,
If you set a password on the private key, seahorse will ask you for the password, and give you the option to unlock the private key at login time. I think this only has to be done once.