This document describes the support for performing SSH authentication with X.509 certificates. Authentication to SSH can be completed using a number of different methods. Public key, password and keyboard interactive are supported in EOS. Certificate login is a type of public key authentication in which the public key does not have to be stored on the server. Instead trusted certificate authorities are installed. A presented certificate must be signed either directly or indirectly by one of these trusted certificate authorities to allow authentication to the device. Support for OpenSSH certificates (also known as SSH Certificates) was added in 4.22.1F.