SSH is probably the most secure way of connecting remotely to your servers and virtual machines. However, no matter how strong the protocol is, the user and their credentials is usually the weak spot. That's why a lot of companies (the bigger, the more likely) require Multi-Factor Authentication by policy where ever possible. Here's how to set up and configure MFA with keypair and server-side password, or server-side password and Google Authenticator for SSH in FreeBSD.