SSH Key-Pair Authentication

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/debian/.ssh/id_rsa): # Enter or input changes if you want
Created directory '/home/debian/.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/debian/.ssh/id_rsa
Your public key has been saved in /home/debian/.ssh/
The key fingerprint is:
The key's randomart image is:

debian@dlp:~$ll ~/.ssh

total 8
-rw------- 1 debian debian 2655 Aug 17 13:48 id_rsa
-rw-r--r-- 1 debian debian 574 Aug 17 13:48
debian@dlp:~$mv ~/.ssh/ ~/.ssh/authorized_keys

Transfer the private key created on the Server to a Client, then it’s possible to login with Key-Pair authentication. Below is an example to connect from a linux shell. Continue reading “SSH Key-Pair Authentication” »


Generating an SSH Key Pair on Windows Using the PuTTYgen and use it on OCI with machine instance

The PuTTYgen program is part of PuTTY, an open source networking client for the Windows platform.
To generate an SSH key pair on Windows using the PuTTYgen program:

  1. Download and install PuTTY or PuTTYgen.To download PuTTY or PuTTYgen, go to and click the You can download PuTTY here link.
  2. Run the PuTTYgen program.The PuTTY Key Generator window is displayed.
  3. Set the Type of key to generate option to SSH-2 RSA.
  4. In the Number of bits in a generated key box, enter 2048.
  5. Click Generate to generate a public/private key pair.As the key is being generated, move the mouse around the blank area as directed. (Optional) Enter a passphrase for the private key in the Key passphrase box and reenter it in the Confirm passphrase box.
  6. Click Save private key to save the private key to a file. To adhere to file-naming conventions, you should give the private key file an extension of .ppk (PuTTY private key). Note: The .ppk file extension indicates that the private key is in PuTTY’s proprietary format. You must use a key of this format when using PuTTY as your SSH client. It cannot be used with other SSH client tools. Refer to the PuTTY documentation to convert a private key in this format to a different format.
  7. Select all of the characters in the Public key for pasting into OpenSSH authorized_keys file box.Make sure you select all the characters, not just the ones you can see in the narrow window. If a scroll bar is next to the characters, you aren’t seeing all the characters.


    ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAQEA0Bp2Pf+u2KfbackWAjOYbtT1Ub8oLhWFrAShUqXk5QjDZI2K/p8y/9sY3S9bNJThWvdFFsY7EjQZmiEL1vlj+/AaZ3/Ht3/WHR9R6zOeEr3nDxoN13jVZH9QU0a7028xf2R35Y4a3CI3TOCUPnvJN2B38rZ9Ruz/HMjOrEit7PhKSJ2OD2xdqVHI3lDXQ75aO1r79kC3lYL7PD+R0zHjtj0ugwbd97SUB02T85yjeJelBfHFni62vC+MF9bo0h0ZMKqP1PYKhxkgYTv+vK+ZxNoLgNOeTDf8HDvkHBuSTnuJL5tF8VEakIJ2uK9ht8uSKtQcNcrmtTmYlIcCI6THOw== rsa-key-20220629
  8. Right-click somewhere in the selected text and select Copy from the menu.
  9. Open a text editor and paste the characters, just as you copied them. Start at the first character in the text editor, and do not insert any line breaks.
  10. Save the text file in the same folder where you saved the private key, using the .pub extension to indicate that the file contains a public key.
    1. If you or others are going to use an SSH client that requires the OpenSSH format for private keys (such as the ssh utility on Linux), export the private key:On the Conversions menu, choose Export OpenSSH key.
    2. Save the private key in OpenSSH format in the same folder where you saved the private key in .ppk format, using an extension such as .openssh to indicate the file’s content.