If you are rebuilding the ssh keys for a user who has accidentally destroyed their files inside .ssh directory
Step 1: Generate the Private Key
# ssh-keygen -t rsa
Step 2: Generate the Public Key from Private Key
# ssh-keygen -y -f ~/.ssh/id_rsa > ~/.ssh/id_rsa.pub
Step 3: Generate the Authorized Key
# cat .ssh/id_rsa.pub >> .ssh/authorized_keys
Step 4: Generate Config File
# touch ~/.ssh/config
StrictHostKeyChecking no