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AlmaLinux 9.1 ; Authenticated SSH connection with key pair

SSH connection with authentication using public key cryptography

Create public and private key pairs

Create a public/private key pair for a user connecting to a Linux server using OpenSSH.
Use ssh-keygen to create the key pair.
The creation of a public/private key pair must be done as a user with remote login privileges.
If you do not specify the destination and file name, id_ed25519 and will be created in /home/(user name)/.ssh/. On the way, enter the password for the key.

Save the created private key id_ed25519 to an appropriate location on windows using winSCP.
Start Winscp
Host name  : Server IP Address
Port number : SSH Port
User name : Server Login User
Password : Password for the above user
Click "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

When connected, the right column is the server side and the left column is the PC (Windows) side.
Save the file "id_ed25519" in the .ssh directory to an appropriate location on Windows in the left column.

Edit SSH configuration file

Edit the SSH configuration file to disable password authentication.

How to connect using Tera Term

Start Tera Term, and select "File" menu "New connection"

Host : Server IP Address
TCP port : SSH Port number

If you get the following security warning "Replace...." and click "Continue".

User name : Login User Name
Password :Password specified in the creation of a public/private key pair
Use RSA/DSA/ECDSA/ED25519 key to log in Private key file: "id_ed25519" saved in Windows.

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 under the name "id_ed25519.ppk" with the extension ".ppk" in the same place as "id_ed25519" saved on the Windows side.

Select the appropriate server,  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 with Tera Term
"Use RSA/DSA/ECDSA/..." "Prive key file" field  : Specify "id_ed25519.ppk" saved in windows

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