https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9600/software/release/17-6/configuration_guide/sec/b_176_sec_9600_cg/x_509v3_certificates_for_ssh_authentication.html
Security Configuration Guide, Cisco IOS XE Bengaluru 17.6.x (Catalyst 9600 Switches) - X.509v3...
X.509v3 Certificates for SSH Authentication