OpenSSH : SSH Key-Pair Authentication2022/01/07
Configure SSH server to login with Key-Pair Authentication.
Create a private key for client and a public key for server to do it.
|||Create Key-Pair by each user, so login with a common user on SSH Server Host and work like follows.|
# create key-pair
Generating public/private rsa key pair. Enter file in which to save the key (/home/cent/.ssh/id_rsa): # Enter or input changes if you want Created directory '/home/cent/.ssh'. Enter passphrase (empty for no passphrase): # set passphrase (if set no passphrase, Enter with empty) Enter same passphrase again: Your identification has been saved in /home/cent/.ssh/id_rsa Your public key has been saved in /home/cent/.ssh/id_rsa.pub The key fingerprint is: SHA256:yYOKaIcT25Jd0ZaOOYLa+rgrU0c/M/rVmJx4q4MVZB0 email@example.com The key's randomart image is: ..... .....[cent@dlp ~]$
total 8 -rw-------. 1 cent cent 2655 Jan 7 19:07 id_rsa -rw-r--r--. 1 cent cent 575 Jan 7 19:07 id_rsa.pub[cent@dlp ~]$
mv ~/.ssh/id_rsa.pub ~/.ssh/authorized_keys
|||Transfer the private key created on the Server to a Client, then it's possbile to login with Key-Pair authentication.|
# transfer the private key to the local ssh directory
scp firstname.lastname@example.org:/home/cent/.ssh/id_rsa ~/.ssh/
email@example.com's password: id_rsa 100% 1876 193.2KB/s 00:00[cent@node01 ~]$
Enter passphrase for key '/home/cent/.ssh/id_rsa': # passphrase if you set[cent@dlp ~]$
|||If you set [PasswordAuthentication no], it's more secure.|
# line 65 : change to [no]
# line 69 : if it's enabled, change it to [no], too
# Change to no to disable s/key passwords
systemctl restart sshd
SSH Key-Pair Authentication on Windows Client #1
This is the example to login to SSH server from Windows Client.
On this example, it uses Putty.
Before it, Transfer a private key to Windows Client.
|||Run [Puttygen.exe] that is included in [Putty]. (placed in the same folder with [Putty.exe])
If not included, Download it from the official site (www.chiark.greenend.org.uk/~sgtatham/putty/).
After starting [Puttygen.exe], Click [Load] button on the following window.
|||Specify the private key that you transfered from SSH server, then passphrase is required like follows, answer it. (if not set passphrase, this step is skipped)|
|||Click the [Save private key] button to save it under a folder you like with any file name you like.|
|||Start Putty and Open [Connection] - [SSH] - [Auth] on the left pane, then specify your private key on the [Private key file] field.|
|||Back to the [Session] on the left pane and specify your SSH server host to Connect.|
|||When SSH key-pair is set, the passphrase if it is set is required to login like follows, then answer it.|
SSH Key-Pair Authentication on Windows #2
|||If you are using Windows 11 like here , OpenSSH Client has been implemented as a Windows feature, so it's possbile to authenticate with SSH Key-Pair without Putty and other 3rd party softwares. Transfer your private key to your Windows and put it under the [(logon user home).ssh] folder like follows, then it's ready to use Key-Pair authentication.|