Canon LBP6780x Manual page 698

Click [Browse...] to select the key/certificate file or enter the directory for the saved key/certificate file.
NOTE
About the name of the key/certificate file
Except for the extension up to 20 alphanumeric characters can be specified in [File Path] for the file name.
Specify the file name so that its length is 20 characters or less.
4
Click [Start Installation].
The installation of the key/certificate file starts.
To specify the key pair (the public key and private key) and its certificate in a key/certificate file installed on this printer so
that you can use them in the printer, see
public key and private key) and its certificate in the printer after installing the key/certificate file.
"Registering a Key and Its Certificate in the Printer " and register the key pair (the