Use SSH keys for authentication when you are connecting to your server, or even between your servers. They can greatly simplify and increase the security of your login process. When keys are implemented correctly they provide a secure, fast, and easy way of accessing your cloud server.
Set up your first SSH keys
I'm using Windows 7 Enterprise and have full administrative privileges. When I run the following command from the Git Bash command line: ssh-keygen -t rsa -C '[email protected]'. 7) Enter the key passphrase and confirm it. 8) Click the button ‘Save private key’ to save the private key. 9) Click the button ‘Save public key’ to save the public key. 10) Make sure to copy the text in the field ‘Public key for pasting into openSSH authorized keys file. That is how we can generate SSH key in Windows using putty. 7) Enter the key passphrase and confirm it. 8) Click the button ‘Save private key’ to save the private key. 9) Click the button ‘Save public key’ to save the public key. 10) Make sure to copy the text in the field ‘Public key for pasting into openSSH authorized keys file. PuTTYgen is a key generator tool for creating pairs of public and private SSH keys. It is one of the components of the open-source networking client PuTTY. Although originally written for Microsoft Windows operating system, it is now officially available for. Enter a key comment, which will identify the key (useful when you use several SSH keys). Type in the passphrase and confirm it. The passphrase is used to protect your key. You will be asked for it when you connect via SSH. Click 'Save private key' to save your private key. Click 'Save public key' to save your public key. Create an SSH key. Follow these steps if you don't already have an SSH key for an account. If you do have an SSH key and you want to generate another key, you'll have to use the terminal because you can't use Sourcetree to create a second key. Creating an SSH key looks something like this: From the Sourcetree menu, select Preferences.
Follow our guide and learn how to set up your first SSH keys for authentication using OpenSSH or PuTTYTray.
Preparing your server
To add an SSH key pair, first, create a hidden folder to your user account home directory on your cloud server with the following command.
Then restrict the permissions to that directory to just yourself with the command below.
This creates a secure location for you to save your SSH keys for authentication. However, note that since the keys are stored in your user home directory, every user that wishes to connect using SSH keys for authentication has to repeat these steps on their own profile.
Using OpenSSH to generate a key pair
Now continue on your own computer if you are using Linux or any other OS that has OpenSSH. PuTTY users should skip to the next section.
1. Generate a new key pair in a terminal with the next command
The key generator will ask for location and file name to which the key is saved to. Enter a new name or use the default by pressing enter.
2. (Optional) Create a passphrase for the key when prompted
This is a simple password that will protect your private key should someone be able to get their hands on it. Enter the password you wish or continue without a password. Press enter twice. Note that some automation tools might not be able to unlock passphrase-protected private keys.
3. Copy the public half of the key pair to your cloud server using the following command
Replace the user and server with your username and the server address you wish to use the key authentication on.
This also assumes you saved the key pair using the default file name and location. If not, just replace the key path ~/.ssh/id_rsa.pub above with your own key name.
Enter your user account password for that SSH server when prompted.
You can now authenticate to your server with the key pair, but at the moment you would need to enter the passphrase every time you connect.
4. (Optional) Set up SSH Agent to store the keys to avoid having to re-enter passphrase at every login
Enter the following commands to start the agent and add the private SSH key.
Type in your key’s current passphrase when asked. If you saved the private key somewhere other than the default location and name, you’ll have to specify it when adding the key.
Afterwards, you can connect to your cloud server using the keys for authentication, and only having to unlock the key by repeating the last 2 steps once after every computer restart.
Using PuTTYTray to generate a key pair
If you are running Windows and PuTTYTray for SSH, you can use the built-in key generator from PuTTY to create a new key pair.
1. Click the Keygen button at the bottom of the PuTTY Configuration window to get started.
Then in the Key Generator window, check that the Type of key to generate at the bottom is set to SSH-2 RSA. The older SSH-1 was the first version on the standard but is now generally considered obsolete. Most modern servers and clients support SSH-2.
2. Click the Generate button to begin.
3. Keep moving your mouse over the blank area in any manner to help generate randomness for a few moments until the progress is complete.
With the keys finished, PuTTY will show the relative information about the pair along with the public key for easier copying.
4. (Optional) Enter a key passphrase in the 2 empty fields for the added security before continuing. The passphrase will protect your key from unauthorized use should someone be able to copy it. However, some automation tools might not be able to unlock passphrase-protected private keys.
Reading the API of you should try this with even if the key pair isn't a certificate (which is speculated by the method description of opensslpkeygetpublic):opensslpkeynew generates a new private and public key pair. The public component of the key can be obtained using opensslpkeygetpublic.You don't have a certificate, so the PEM to DER will likely fail. You should amend it to comply to the representation of the public key. Tutorial generate public and private key mac office. The base 64 decoding is correct, but make sure you got the right header, footer and structure.
5. Click the Save private key button and store it somewhere safe. Generally anywhere in your user directory is fine as long as your PC is password protected. Before closing the keygen, you may want to copy the public key to your clipboard, but you can always get it later as well.
Now that you have a new key saved on your computer, you’ll need to import it into the PuTTY key agent.
6. Click the Agent button to open the key manager in the PuTTY Configuration window.
7. Click Add Key button in the Key List, then browse to the location you saved the private key, select it and click Open.
Enter your key passphrase if asked.
This will import the key to your PuTTY client, but you still need to copy the public key over to your server.
8. Open an SSH connection to your cloud server and go to the SSH key directory.
9. Open or create the default file OpenSSH looks for public keys called authorized_keys.
10. Paste the public key into the file by simply right-clicking the SSH client window. Make sure the key goes on a single line for OpenSSH to be able to read it.
When you’ve copied the public key over to the authorized keys list, save the file and exit the editor. You can now test the public key authentication by logging in to your server again. You should not get asked for your password, but instead logged straight in with the key. If it’s not working, check that your private key is unlocked at your SSH Agent and try again.
Turn off password authentication
With SSH key authentication configured and tested, you can disable password authentication for SSH all together to prevent brute-forcing. When logged in to your cloud server.
1. Open the SSH configuration file with the following command.
2. Set the password authentication to no to disable clear text passwords.
3. Check that public key authentication is enabled, just to be safe and not get locked out from your server. If you do find yourself unable to log in with SSH, you can always use the Web terminal at your UpCloud control panel.
Then save and exit the editor.
Generate Ssh Key Windows Git
4. Restart the SSH service to apply the changes by using the command below.
With that done your cloud server is now another step along towards security. Malicious attempts to connect to your server will results in authentication rejection, as plain passwords are not allowed, and brute-forcing an RSA key is practically impossible.
Conclusions
Remember to always keep your private keys safe. You can use the same key from multiple computers if you wish, or generate new ones on each client connecting to your cloud server for added security. Each user should generate their own key pair and passphrase for secure access control. With proper management, even in case one of the private keys gets compromised you won’t have to replace them all.
Introduction
Secure Shell (SSH) is an encrypted protocol used by Linux users to connect to their remote servers.
Generally, there are two ways for clients to access their servers – using password based authentication or public key based authentication.
Using SSH keys for authentication is highly recommended, as a safer alternative to passwords.
This tutorial will guide you through the steps on how to generate and set up SSH keys on CentOS 7. We also cover connecting to a remote server using the keys and disabling password authentication.
1. Check for Existing Keys
Prior to any installation, it is wise to check whether there are any existing keys on the client machines.
Open the terminal and list all public keys stored with the following command:
The output informs you about any generated keys currently on the system. If there aren’t any, the message tells you it cannot access
/.ssh/id_*.pub , as there is no such file or directory.
2. Verify SSH is Installed
To check if thw package is installed, run the command:
If you already have SSH, the output tells you which version it is running. Currently, the latest version is OpenSSH 8.0/8.0p1.
Generate Ssh Key File In Windows
Note: Refer to our guide If you need to install and enable SSH on your CentOS system.
Steps to Creating SSH keys on CentOSStep 1: Create SSH Key Pair
1. Start by logging into the source machine (local server) and creating a 2048-bit RSA key pair using the command:
If you want to tighten up security measures, you can create a 4096-bit key by adding the -b 4096 flag:
2. After entering the command, you should see the following prompt:
3. To save the file in the suggested directory, press Enter. Alternatively, you can specify another location.
Note: If you already have a key pair in the proposed location, it is advisable to pick another directory. Otherwise it will overwrite existing SSH keys.
4. Next, the prompt will continue with:
Although creating a passphrase isn’t mandatory, it is highly advisable.
5. Finally, the output will end by specifying the following information:
Now you need to add the public key to the remote CentOS server.
You can copy the public SSH key on the remote server using several different methods:
The fastest and easiest method is by utilizing
ssh-copy-id . If the option is available, we recommend using it. Otherwise, try any of the other two noted.
1. Start by typing the following command, specifying the SSH user account, and the IP address of the remote host:
If it is the first time your local computer is accessing this specific remote server you will receive the following output:
2. Confirm the connection – type yes and hit Enter.
3. Once it locates the
id_rsa.pub key created on the local machine, it will ask you to provide the password for the remote account. Type in the password and hit Enter.
4. Once the connection has been established, it adds the public key on the remote server. This is done by copying the
~/.ssh/id_rsa.pub file to the remote server’s ~/.ssh directory. You can locate it under the name authorized_keys .
5. Lastly, the output tells you the number of keys added, along with clear instructions on what to do next:
1. First, set up an SSH connection with the remote user:
2. Next, create the
~/.ssh directory as well as the authorized_keys file:
3. Use the chmod command to change the file permission:
chmod 700 makes the file executable, while chmod 600 allows the user to read and write the file.
4. Now, open a new terminal session, on the local computer.
5. Copy the content from
id_rsa.pub (the SSH public key) to the previously created authorized_keys file on the remote CentOS server by typing the command:
With this, the public key has been safely stored on the remote account.
1. To manually add the public SSH key to the remote machine, you first need to open the content from the
~/.ssh/id_rsa.pub file:
2. As in the image below, the key starts with ssh-rsa and ends with the username of the local computer and hostname of the remote machine:
3. Copy the content of the file, as you will need later.
4. Then, in the terminal window, connect to the remote server on which you wish to copy the public key. Use the following command to establish the connection:
5. Create a ~/.ssh directory and authorized_keys file on the CentOS server with the following command:
6. Change their file permission by typing:
7. Next, open the
authorized_keys file with an editor of your preference. For example, to open it with Nano, type:
8. Add the public key, previously copied in step 2 of this section, in a new line in (under the existing content).
9. Save the changes and close the file.
10. Finally, log into the server to verify that everything is set up correctly.
Once you have completed the previous steps (creating an RSA Key Pair and copying the Public Key to the CentOS server), you will be able to connect to the remote host without typing the password for the remote account.
All you need to do is type in the following command:
If you didn’t specify a passphrase while creating the SSH key pair, you will automatically log in the remote server.
Otherwise, type in the passphrase you supplied in the initial steps and press Enter.
Once the shell confirms the key match, it will open a new session for direct communication with the server.
Although you managed to access the CentOS server without having to provide a password, it still has a password-based authentication system running on the machine. This makes it a potential target for brute force attacks.
However I’ve added them to the config.txt file as suggested (through the Pi Config add-on), and after a reboot there seems to be no change. So now I now which one is which. Raspberry mpeg-2 license key generator. I received a confirmation email with both licences in it, related to the serials of either Pi.
You should disable password authentication entirely by following the outlined steps.
Note: Consider performing the following steps through a non-root account with sudo privileges, as an additional safety layer.
1. Using the SSH keys, log into the remote CentOS server which has administrative privileges:
2. Next, open the SSH daemon configuration file using a text editor of your choice:
3. Look for the following line in the file:
4. Edit the configuration by changing the
yes value to no . Thus, the directive should be as following:
5. Save the file and exit the text editor.
6. To enable the changes, restart the sshdservice using the command:
7. Verify the SSH connection to the server is still functioning correctly. Open a new terminal window and type in the command:
In this article, you learned how to generate SSH key pairs and set up an SSH key-based authentication. We also covered copying keys to your remote CentOS server, and disabling SSH password authentication.
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