To provision additional security keys, restore the master key backup and repeat the [Configure Smartcard](#configure-smartcard) procedure.
@ -2192,7 +2192,7 @@ On the remote host, type `ssh-add -l` - if you see the ssh key, that means forwa
**Note** Agent forwarding may be chained through multiple hosts - just follow the same [protocol](#remote-host-configuration) to configure each host.
# Multiple Keys
# Using Multiple Keys
To use a single identity with multiple YubiKeys - or to replace a lost card with another - issue this command to switch keys:
@ -2364,7 +2364,7 @@ Admin PIN: 12345678
- If it still fails, it may be useful to stop the background `sshd` daemon process service on the server (e.g. using `sudo systemctl stop sshd`) and instead start it in the foreground with extensive debugging output, using `/usr/sbin/sshd -eddd`. Note that the server will not fork and will only process one connection, therefore has to be re-started after every `ssh` test.
- If you receive the error, `Please insert the card with serial number: *` see [management of multiple keys](#multiple-keys).
- If you receive the error, `Please insert the card with serial number: *` see [using of multiple keys](#using-multiple-keys).
- If you receive the error, `There is no assurance this key belongs to the named user` or `encryption failed: Unusable public key` use `gpg --edit-key` to set `trust` to `5 = I trust ultimately`.