Contents
SSH connection with authentication using public key cryptography
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@Alma~]$ ssh-keygen -t ed25519 Generating public/private ed25519 key pair. Enter file in which to save the key (/home/huong/.ssh/id_ed25519): 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:jkWIZvNhc5fHRioH3nTrTz7CLlbjVaOMmmkuKFaW1tY huong@Alma The key's randomart image is: +--[ED25519 256]--+ | . . o | | . o + * . | | = = = * = | | o + = + + ..| | + S + o..| | = * E oo*. | | + + . +ooo+ | | o . . =o... . | | . . +o .. | +----[SHA256]-----+ |
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$ cat ~/.ssh/id_ed25519.pub >> ~/.ssh/authorized_keys $ chmod 600 ~/.ssh/authorized_keys $ chmod 700 ~/.ssh/ |
Save the created private key id_ed25519 to an appropriate location on windows using winSCP.
Start Winscp and click "New Session
Host name : Server IP Address
Port number : SSH port number
User name : Server Login User
Password : Password for the same user
Click "Save"
![](https://korodes.com/wp-content/uploads/2024/04/b2391de24d14cbe62174c855472ce049.png)
Site name : Any name
Click "OK"
![](https://korodes.com/wp-content/uploads/2024/04/99801ac287bd8fd41e430b2a4be8949e.png)
After confirming the server, click "Login".
![](https://korodes.com/wp-content/uploads/2024/04/4dfda056ba965fd6285767d287f532c3.png)
Click "Update" when the following screen appears
![](https://korodes.com/wp-content/uploads/2024/04/4ae9e30643a31608929f7e2a563962d9.png)
Password of the logged-in user in the Password field
![](https://korodes.com/wp-content/uploads/2024/04/de5adebe85aa65fd95e17aaaf40c52fc.png)
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.
![](https://korodes.com/wp-content/uploads/2024/04/e2ed9e5a5fd05671393dcb860808138d.png)
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 with Tera Term
Start Tera Term, and select "File" menu "New connection"
![](https://korodes.com/wp-content/uploads/2024/04/28ef008fc415f50c5f2e6494e6e7dc6d.png)
Host : Server IP Address
TCP port : SSH port number
![](https://korodes.com/wp-content/uploads/2024/04/34c7e1eb718d02b0340eb810a580beba.png)
If you get the following security warning Check "Replace...." and click "Continue".
![](https://korodes.com/wp-content/uploads/2024/04/8ddec1d665643287cf8112425863e453.png)
User name : Login User Name
Password : Password specified in the creation of a public/private key pair
Under "Use RSA/DSA/ECDSA/ED25519 key to log in", set "Private key file:" to "id_ed25519" that you just saved in Windows. and click "OK".
![](https://korodes.com/wp-content/uploads/2024/04/a6cc9781c5227827441959b881a59ae6.png)
Creating a private key using PuTTYgen
Start Winscp and launch [Run Puttygen] from [Tools].
Select the appropriate server
![](https://korodes.com/wp-content/uploads/2024/04/985aefd767cbd2355148e0cdc529366c.png)
Click Load
![](https://korodes.com/wp-content/uploads/2024/04/00c428ccb07d4a7fdd82f9d39edb1569.png)
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.
![](https://korodes.com/wp-content/uploads/2024/04/e6989c51a15e5e58de4f3dd94ee5bfd2.png)
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2024/04/9d9f601c2f41cb235b7c7e0022a07598.png)
![](https://korodes.com/wp-content/uploads/2024/04/3a00e9f9d7adefb3c813d41b96e21f95.png)
Click on "Save private key"
![](https://korodes.com/wp-content/uploads/2024/04/04f746ce38d7d5eb4f08efe84f9497be.png)
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".
![](https://korodes.com/wp-content/uploads/2024/04/e42946b6cb08e94d8528b8b9582ac6d8.png)
Select the appropriate server and click "Edit"
![](https://korodes.com/wp-content/uploads/2024/04/7bfb1210944941910457e567daf64f66.png)
Click on "Advanced"
![](https://korodes.com/wp-content/uploads/2024/04/c237661fc065aac7c3fad54326cee1d1.png)
Open the "Authentication" menu and specify "id_ed25519.ppk" saved in Windows for "Private key file
![](https://korodes.com/wp-content/uploads/2024/04/4eea215e99f53dbc28dda0831f9d4943.png)
Click "Save"
![](https://korodes.com/wp-content/uploads/2024/04/1a6851dfa5eac979e8e46080b226513e.png)
Click on "Login"
![](https://korodes.com/wp-content/uploads/2024/04/8ed6731f61acb015badf2fb476caabfd.png)
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2024/04/fa2981527d424cf586c0c2612e541cf0.png)
When connecting with Tera Term, use the following
Use RSA/DSA/ECDSA/..." Specify "id_ed25519.ppk" saved in windows in the "Use RSA/DSA/ECDSA/..." field.
![](https://korodes.com/wp-content/uploads/2024/04/c9f2082131c76fb20b6e33f86d38901c.png)