As of 2016, RSA is still considered strong, but the recommended key length has increased over time. Originally, with SSH protocol version 1 (now deprecated) only the RSA algorithm was supported. The SSH client and key agent are enabled and available by default and the SSH server is an optional Feature-on-Demand.
OpenSSH-based client and server programs have been included in Windows 10 since version 1803. These keys differ from keys used by the related tool GNU Privacy Guard. To provide for unattended operation, the passphrase can be left empty, albeit at increased risk. With the help of the ssh-keygen tool, a user can create passphrase keys for any of these key types. Ssh-keygen is able to generate a key using one of three different digital signature algorithms. The ssh-keygen utility is used to generate, manage, and convert authentication keys. Ssh-keygen is a standard component of the Secure Shell (SSH) protocol suite found on Unix, Unix-like and Microsoft Windows computer systems used to establish secure shell sessions between remote computers over insecure networks, through the use of various cryptographic techniques. Protocol suite found on Unix, Unix-like and Microsoft Windows computer systems used ssh-keygen Developer(s)
