Quick Guide to ssh Keys

A quick guide for using ssh keys instead of passwords for ssh login.

ssh-keygen

generate a new ssh key with ssh-keygen command. Since RSA is being depricated use ecdsa or

ssh-keygen -f ~/.ssh/mynewkey-ecdsa -t ecdsa -b 521

It asks for adding password to it, leave it blank. If not managing lots of keys, but only using one, just use default filename without the -f

ssh-keygen -t ecdsa -b 521

ssh-copy-id

To copy the key to other linux hosts authorized_keys file

ssh-copy-id -i ~/.ssh/mynewkey-ecdsa bob@192.168.33.44

in Windows the ssh-copy-id command does not exist, so instead you can use this workaround

and then you can reference the keys in your ssh config file, for even easier login. If using default keyname then this is not required.

Example ~/.ssh/config

Host myserver1 myserver1.mydomain
   Hostname 192.168.33.44
   user bob
   IdentityFile ~/.ssh/mynewkey-ecdsa

Host myserver2 myserver2.mydomain
   Hostname 192.168.33.55
   user bob
   IdentityFile ~/.ssh/mynewkey-ecdsa

Test the configuration

then you can login using the key simply with

ssh myserver1

Further Reading

For more info on using ssh-keygen and ssh-copy see Redhat RHEL9 admin guide or Ubuntu24 openssh-server guide