Contents
SSH connection with authentication using public key
Creation of public and private key pairs
Create a public/private key pair for a user connecting to the Linux server using OpenSSH.
Use ssh-keygen to create key pairs.
Creation of public/private key pairs is performed with remote login user privileges.
If you do not specify the destination and file name, id_ed25519 and id_ed25519.pub will be created in /home/(user name)/.ssh/. On the way, enter the password for the key.
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# su - huong [huong@Lepard ~]$ ssh-keygen -t ed25519 Generating public/private ed25519 key pair. Enter file in which to save the key (/home/huong/.ssh/id_ed25519): Created directory '/home/huong/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/huong/.ssh/id_ed25519 Your public key has been saved in /home/huong/.ssh/id_ed25519.pub The key fingerprint is: SHA256:nyMTMTY7dRG3wjOpYWNetDJ52yxsMRDeF5AEYLfenKM huong@Lepard The key's randomart image is: +--[ED25519 256]--+ | o.=+*+o | | . o B.= o | | = % # o | | . @ & % | | S + X o | | + + o | | o E | | o . | | | +----[SHA256]-----+ |
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$ cat ~/.ssh/id_ed25519.pub >> ~/.ssh/authorized_keys $ chmod 600 ~/.ssh/authorized_keys $ chmod 700 ~/.ssh/ |
Save the generated private key id_ed25519 to the Windows directory c:\USERS\user\.ssh\ using winSCP
Start Winscp
Host name : Server IP Address
Port number : SSH Port
User name : Server Login User
Password : Password for the same user
and then "Save".
Site name : Any name
Click "OK"
After confirming the server, click "Login".
Click "Update" when the following screen appears
Password of the logged-in user in the Password field
Once connected, the left pane shows the server side, and the right pane shows the PC (Windows) side.
Copy the "id_ed25519" file located in the .ssh directory to the Windows directory [c:\USERS\user\.ssh] on the right side.
Editing SSH Configuration File
Edit the SSH configuration file to disable password authentication.
This time, instead of being an ordinary user, su - to become root.
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$ su - Password: # vi /etc/ssh/sshd_config # Line 65 : Changed to no password authentication PasswordAuthentication no # systemctl restart sshd |
How to connect using Tabby Terminal
Specify the key using the option [-i c:\USERS\xxxxx\.ssh\id_ed25519]
C:\Users\xxxxx>ssh huong@192.168.11.83 -p 2244 -i c:\USERS\xxxxx\.ssh\id_ed25519
Enter passphrase for key 'c:\USERS\xxxxx\.ssh\id_ed25519': [The password created when generating the public key]
Web console: https://Lepard:9090/ or https://192.168.11.83:9090/
Last login: Mon Dec 8 13:23:17 2025 from 192.168.11.6
huong@Lepard:~$
Creating a private key using PuTTYgen
Start Winscp and launch [Run Puttygen] from [Tools].
Select the appropriate server
Click Load
The [ Open File Dialog ] will open, change the file type to [ All Files (*. Change the file type to [ All Files (*. *) ] and load the private key id_ed25519 that was transferred from the Linux server.
The password is the password set in "Creating a public and private key pair" above
Click on "Save private key"
Save the file with the extension ".ppk" in the same place as "id_ed25519" saved earlier on the Windows side under the name "id_ed25519.ppk".
Select the appropriate server and click "Edit"
Click on "Advanced"
Open the "Authentication" menu and specify "id_ed25519.ppk" saved in Windows for "Private key file
Click "Save"
Click on "Login"
The password is the password set in "Creating a public and private key pair" above
When connecting via Tabby Terminal, do the following:
C:\Users\xxxxx>ssh huong@192.168.11.83 -p 2244 -i c:\USERS\xxxxx\.ssh\id_ed25519.ppk
Enter passphrase for key 'c:\USERS\xxxxx\.ssh\id_ed25519.ppk': ←The password specified when creating the public key
Web console: https://Lepard:9090/ or https://192.168.11.83:9090/
Last login: Sat Nov 29 11:12:15 2025 from 192.168.11.6
If you encounter an error like the one below, convert your private key to OpenSSH format.
C:\Users\xxxxx>ssh huong@192.168.11.83 -p 2244 -i c:\USERS\xxxxx\.ssh\id_ed25519.ppk
Load key "c:\USERS\xxxxx\.ssh\id_ed25519.ppk": invalid format
huong@192.168.11.83: Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
Launch [WinSCP] > [Run PuTTygen], then import the private key under [Import key] in the [Conversions] tab.
Convert the imported private key to OpenSSH format and save it under a different name
The password specified when creating the public key
Can be connected as follows
C:\Users\xxxxx>ssh huong@192.168.11.83 -p 2244 -i c:\USERS\xxxxx\.ssh\id_ed25519_2.ppk
Enter passphrase for key 'c:\USERS\xxxxx\.ssh\id_ed25519_2.ppk': ←The password specified when creating the public key
Web console: https://Lepard:9090/ or https://192.168.11.83:9090/
Last login: Mon Dec 8 13:24:05 2025 from 192.168.11.6
