Setup public key based authentication for windows

Please note key based authentication is not supported for AAD users. Refer to https://github.com/PowerShell/Win32-OpenSSH/issues/1787.

On the client machine, create the public/private key pair.

1. cd to <openssh_binary_folder>

2. Create the key pair.

   ssh-keygen.exe -t rsa -f $env:USERPROFILE\.ssh\id_rsa

   Enter the passphrase (or) hit enter to skip the passphrase.

On the server machine, execute the below commands.

1. Open the PowerShell window. Admin users require elevated PowerShell window.

2. Manually copy the public key to the server machine.

3. If you are an admin user and using default sshd_config then

   i. Copy the public key

   cp <public_key_absolute_path> "$env:programdata\ssh\administrators_authorized_keys"

   Please note administrators_authorized_keys is the file name without any extension.

   ii. set the right ACLs using one of the host private key file.

   get-acl "$env:programdata\ssh\ssh_host_rsa_key" | set-acl "$env:programdata\ssh\administrators_authorized_keys"

4. For non-admin users,

   copy the public key to authorized_keys file (without any extension).

   cp <public_key_absolute_path> $env:USERPROFILE\.ssh\authorized_keys
   

   If you don't have .ssh folder under $env:USERPROFILE folder then manually create it

From the client machine, try the key-based authentication

ssh user@domain@ip -i <private_key_absolute_path> (Domain users)
ssh user@ip -i <private_key_absolute_path> (local users)

Please note, if you have private_key in "$env:USERPROFILE\.ssh" directory then you don't need to pass the private_key_absolute_path

_If you are using your own keys (instead of generating new ssh keys) then please make sure the file encoding is set to UTF-8