How to setup SSH in AIX to communicate with HMC

Download authorized_keys2 file from HMC
scp hscroot@HMC:/home/hscroot/.ssh/authorized_keys2 authorized_keys2_HMC

Add public key of your user on host:
cat ~/.ssh/id_rsa.pub >> authorized_keys2_HMC

Upload authorized_keys2_HMC file back to HMC
scp authorized_keys2_HMC hscroot@HMC:/home/hscroot/.ssh/authorized_keys2

SSH to HMC to add HMC to known hosts
ssh hscroot@HMC