Contents
RSA 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.
This time, we will create a key set using the RSA cipher used in the SSH protocol Version 2.
The creation of a public/private key pair is performed with remote login user privileges (e.g., huong).
If you do not specify the destination and file name, id_rsa and id_rsa.pub will be created in /home/huong/.ssh/. On the way, enter the password for the key.
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# su - huong huong@debian:~$ /usr/bin/ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/huong/.ssh/id_rsa): 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_rsa Your public key has been saved in /home/huong/.ssh/id_rsa.pub The key fingerprint is: SHA256:/lhLZaXfeCJOzm0TA4wPqQtUgqKn9+W01HRustCcSWs huong@Lepard The key's randomart image is: +---[RSA 3072]----+ | . | | . . . . | | . . o + . | |. . . o = oo | | o . *SB o+. | |. . *.E oo..oo | | . . = =.=o o +oo| | . o o= * ooo | | . o +... | +----[SHA256]-----+ |
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$ chmod 700 ~/.ssh $ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys $ chmod 600 ~/.ssh/authorized_keys |
Use Winscp or other means to save the private key (~/.ssh/id_rsa) in an appropriate location on Windows.
Start Winscp
Host name : Server IP Address
Port number : SSH Port
User name : Server Login User
Password : Password for the same user
「Save」
Site name : Any name
「OK」クリック
After confirming the server, click "Login".
![](https://korodes.com/wp-content/uploads/2022/05/5337a463af46989de0d4cdcd3f2bea8a.png)
Click "Update" when the following screen appears
![](https://korodes.com/wp-content/uploads/2022/05/b0e75504c43c2dec9a5603379c9df40c.png)
Password of the logged-in user in the Password field
![](https://korodes.com/wp-content/uploads/2022/05/100978adf52d2777467003c4ddc335c2.png)
When connected, the right column is the server side and the left column is the PC (Windows) side.
Drag and drop "id.rsa" under /home/huong/.ssh on the server side to the left column Windows and save it.
![](https://korodes.com/wp-content/uploads/2022/05/519270533f8142dce95588e29ab3d794.png)
Edit 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 # Per Line 58 #PasswordAuthentication yes ← Uncomment by deleting # at the beginning of the line and change to the followingPasswordAuthentication noo 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/2022/05/a665f699dd994b53fffe9d6f0ef40826.png)
Host : Server IP Address
TCP port : SSH Port number
![](https://korodes.com/wp-content/uploads/2022/05/c1251b0fdd1def8a04f053e625d7a4e8.png)
If you get the following security warning "Replace.... "check the box and "Continue".
![](https://korodes.com/wp-content/uploads/2022/05/2515e05dc3f751841e52139cdc53c3ec.png)
User name : Login username
Password :Password specified in the creation of a public/private key pair
Check the "Use RSA/DSA...." checkbox. and in the "Private key file" field, specify the "id_rsa" that you just saved in windows.
![](https://korodes.com/wp-content/uploads/2022/05/560eab40d940a29d3b42587e6699d595.png)
Creating a private key using PuTTYgen
Start Winscp and launch "Run Puttygen" from "Tools".
Select the appropriate server
Click Load
![](https://korodes.com/wp-content/uploads/2022/05/6b939ae51b37143f8e081e227bc17233.png)
The [ Open File Dialog ] will open, change the file type to [ All Files (*. *)] and load the private key id_rsa transferred from the Linux server.
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2022/05/60dda6a69c9cdaa70a35c1d5b0f19aec.png)
Save the private key file to windows, file name is "id_rsa.ppk"
Select the appropriate server and click "Edit"
Click on "Advanced"
Select "Authentication" and specify the "id_rsa.ppk" file saved by windows in the "Private key file" field
![](https://korodes.com/wp-content/uploads/2022/05/36497757c7297ff5f47021f59d4e273f.png)
Click "Save"
Click "Login"
![](https://korodes.com/wp-content/uploads/2022/05/2b1ddb882ae31ad5b4ad29f2e3ba436a.png)
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2022/05/e11b1bd8a4e89d286eb0564422f2841e.png)
When connecting with Tera Term, use the following
Use RSA/DSA/ECDSA/..." Specify "id_rsa.ppk" saved in windows in the "Use RSA/DSA/ECDSA/..." field.