- Putty Generate Ssh Private Key Login
- Putty Generate Ssh Private Key File
- Putty Generate Ssh Private Key Extension
- Putty Use Ssh Key
You can use PuTTY to generate SSH keys. PuTTY is a free open-source terminal emulator that functions much like the Terminal application in macOS in a Windows environment. This section shows you how to manually generate and upload an SSH key when working with PuTTY in the Windows environment.
-->With a secure shell (SSH) key pair, you can create virtual machines (VMs) in Azure that use SSH keys for authentication, eliminating the need for passwords to sign in. This article shows you how to quickly generate and use an SSH public-private key file pair for Linux VMs. You can complete these steps with the Azure Cloud Shell, a macOS or Linux host, the Windows Subsystem for Linux, and other tools that support OpenSSH.
Note
VMs created using SSH keys are by default configured with passwords disabled, which greatly increases the difficulty of brute-force guessing attacks.
For more background and examples, see Detailed steps to create SSH key pairs.
For additional ways to generate and use SSH keys on a Windows computer, see How to use SSH keys with Windows on Azure.
Supported SSH key formats
Azure currently supports SSH protocol 2 (SSH-2) RSA public-private key pairs with a minimum length of 2048 bits. Other key formats such as ED25519 and ECDSA are not supported.
Create an SSH key pair
Use the
ssh-keygen
command to generate SSH public and private key files. By default, these files are created in the ~/.ssh directory. You can specify a different location, and an optional password (passphrase) to access the private key file. If an SSH key pair with the same name exists in the given location, those files are overwritten.Warcraft 3 frozen throne cd key generator. The following command creates an SSH key pair using RSA encryption and a bit length of 4096:
If you use the Azure CLI to create your VM with the az vm create command, you can optionally generate SSH public and private key files using the
--generate-ssh-keys
option. The key files are stored in the ~/.ssh directory unless specified otherwise with the --ssh-dest-key-path
option. The --generate-ssh-keys
option will not overwrite existing key files, instead returning an error. In the following command, replace VMname and RGname with your own values:Provide an SSH public key when deploying a VM
To create a Linux VM that uses SSH keys for authentication, specify your SSH public key when creating the VM using the Azure portal, Azure CLI, Azure Resource Manager templates, or other methods:
If you're not familiar with the format of an SSH public key, you can display your public key with the following
cat
command, replacing ~/.ssh/id_rsa.pub
with the path and filename of your own public key file if needed:A typical public key value looks like this example:
If you copy and paste the contents of the public key file to use in the Azure portal or a Resource Manager template, make sure you don't copy any trailing whitespace. To copy a public key in macOS, you can pipe the public key file to
pbcopy
. Similarly in Linux, you can pipe the public key file to programs such as xclip
.Putty Generate Ssh Private Key Login
The public key that you place on your Linux VM in Azure is by default stored in ~/.ssh/id_rsa.pub, unless you specified a different location when you created the key pair. To use the Azure CLI 2.0 to create your VM with an existing public key, specify the value and optionally the location of this public key using the az vm create command with the
--ssh-key-values
option. In the following command, replace VMname, RGname, and keyFile with your own values:If you want to use multiple SSH keys with your VM, you can enter them in a space-separated list, like this
--ssh-key-values sshkey-desktop.pub sshkey-laptop.pub
.SSH into your VM
With the public key deployed on your Azure VM, and the private key on your local system, SSH into your VM using the IP address or DNS name of your VM. In the following command, replace azureuser and myvm.westus.cloudapp.azure.com with the administrator user name and the fully qualified domain name (or IP address):
If you specified a passphrase when you created your key pair, enter that passphrase when prompted during the login process. The VM is added to your ~/.ssh/known_hosts file, and you won't be asked to connect again until either the public key on your Azure VM changes or the server name is removed from ~/.ssh/known_hosts.
If the VM is using the just-in-time access policy, you need to request access before you can connect to the VM. For more information about the just-in-time policy, see Manage virtual machine access using the just in time policy.
Next steps
- For more information on working with SSH key pairs, see Detailed steps to create and manage SSH key pairs.
- If you have difficulties with SSH connections to Azure VMs, see Troubleshoot SSH connections to an Azure Linux VM.
In this project, we will be showing you how to setup Raspberry Pi SSH keys. It’s the perfect way to harden your Pi’s security.
Using SSH Keys for authentication is an excellent way of securing your Raspberry Pi as only someone with the private SSH key will be able to authenticate to your system.
This works by generating an SSH Key pair, you will retain the SSH private key, but the public key will go onto the Raspberry Pi’s operating system.
These SSH keys act as a means of identifying yourself to the SSH server using public-key cryptography and challenge-response authentication.
If you value your security SSH Keys is something you should set up, it offers a few security benefits over password authentication.
For starters, it is much harder for an attacker to be able to intercept and is also much more complicated to brute force. A standard SSH Key is usually 2048 characters long, compared to a password that is no longer than 32 characters.
Equipment List
Below are all the pieces of equipment that I made use of for this Raspberry Pi SSH Keys Authentication tutorial.
Recommended
Raspberry Pi 2 or 3
Micro SD Card
Power Supply
Ethernet Cord (Recommended) or Wifi dongle (Pi 3 has Wifi inbuilt)
Optional
Raspberry Pi Case
Generating SSH Keys on Windows
To generate SSH keys on a Windows-based operating system, we will have to rely on a piece of software called PuTTY.
You can download PuTTY from their website. Make sure you get the full package version as this includes the piece of software that we need to generate the SSH Keys for your Raspberry Pi.
1. Once you have downloaded and installed PuTTY to your computer go ahead and open up the program that was installed alongside it called PuTTYgen.
2. With PuTTYgen opened on your computer, click the “Generate” button as we have shown in the image below.
Pressing this button will generate the public and private SSH keys that we will use to make our SSH connection to our device, in our case this will be the Raspberry Pi.
3. Once PuTTYgen has begun generating the SSH keys it will ask you to move your mouse in the space as we have indicated in the image below.
By doing this, it helps ensure that the SSH key it generates should be genuinely unique and be hard for someone to be able to generate the same key quickly.
4. With the SSH keys now generated, there are a few more things that you need to do.
The first (1.) is to set a name for this SSH key, make this something memorable, so you know what SSH key is required when connecting.
Secondly (2.) you should set a passkey, this ensures that even if someone managed to steal your private SSH key, they would still need to enter a password.
This passkey acts as a second line of defense. If you would prefer not to have to enter a password at all, then you can skip this step and leave the two fields empty.
However, we do not recommend doing this if you value your security.
Thirdly (3.) we need to save the public key and the private key to somewhere safe on the computer. Make a note of the location that you save both of these files as you will need these to make a connection to your Raspberry Pi. Also, make sure you end the files in .ppk so that PuTTY can pick them up.
Finally (4.) copy down the public SSH key that is featured in the text box shown in the image below. You can quickly select all the text by clicking on the box and pressing CTRL + A then CTRL + C.
We will need this text shortly to add to our Linux systems SSH Authorized keys file. Without this, the system won’t be able to see our private key as a proper authentication method.
5. The next steps of this tutorial will walk you through the process of copying the public SSH key to your linux device. In our case, we will be using a Raspberry Pi that is running the Raspbian operating system.
Nwow you can proceed to the section titled “Copying the Public Keys manually” to continue with this Raspberry Pi SSH Keys tutorial.
Generating SSH Keys on Linux based systems
1. Generating SSH keys on a Linux system is a little easier as the SSH tools to do this are usually included with the main operating system. This means we do not have to install any additional packages.
To generate SSH Keys open up a terminal session on your Linux device enter the following command.
2. With the ssh-keygen tool now running you will be first asked to enter a file in which to save the key. For this tutorial, just press Enter to leave this as the default.
Since we are doing this on our Raspberry Pi Raspbian installation, this default directory was located at /home/pi/.ssh/id_rsa.
3. After setting the file in which to save the key we now need to decide whether we want to use a passphrase.
Personally, we recommend that you utilize a passphrase as it ensures that your private key will have a bit of extra security.
This additional security means that even if someone manages to steal the file as they will need to enter the passphrase to decrypt the private key.
So at this step enter a passphrase (Make sure that this is something secure but memorable).
Alternatively, if you do not like having to enter a password, you can press Enter but remember this means that anyone who has your private key can access your device without entering any password.
4. Now you have the choice to either copy your SSH public key by utilizing the ssh-copy-id tool or manually copy the key itself.
If you want to copy the key over manually, then follow step 5 and step 6, otherwise skip to the next section titled “Copying the Public Key using SSH Tools“.
5. The SSH key should now be generated so we can grab the contents of the public key file, we will need the contents of the file for setting up authentication on the device we want to use the SSH keys to authenticate to.
To get the contents of the public key, you can utilize the following command on your Linux based device.
6. With the contents of the public key now handy we can now proceed to the next step of actually adding the SSH key to the authorized_keys file.
Now skip to the section titled “Copying the Public Keys manually” to learn how to utilize the public keys contents to allow the private key to act as an authorization key.
Copying the Public Key using SSH Tools
1. On your Linux device (In our case it’s one of our Raspberry Pis), run the following command. Make sure that you replace IP_ADDRESS with the IP address of the remote machine that you want to copy the keys to.
Please note that you will be asked to log in with both your username and password for that remote machine as the tool needs these to copy over your public key.
Once done, this tool will automatically add your public key to the authorized_keys file on the remote machine.
Copying the Public Keys Manually
1. Back on the Raspberry Pi, we need to utilize a few commands to setup our authorized_keys file. This is the file that the SSH daemon will check when a private key is used for authentication.
To begin let’s create the folder that our authorized_keys file will be sitting in. To do this, we will be using the install command with a few parameters to set the correct permissions.
Run the following command on your Raspberry Pi.
2. With the folder created let’s go ahead and put our public key in the authorized_keys file.
To do this run the following command to begin editing it.
3. In this file copy and paste the contents of the public SSH key that you generated earlier using either your Windows device or your Linux device.
SSH will authenticate any private keys against the public key present to see if it is a legitimate connection to authorize.
4. Once you have your public SSH key entered into the authorized_keys file, you can save and quit out of the file by pressing Ctrl + X then Y and finally Enter.
5. With the file now saved we need to make sure it has the correct permissions. To do this, we need to run the following commands.
These commands will assign the correct permissions to the file so that it can be read by SSH when you try to log in.
If you are not using the default “pi” user on Raspbian make sure you replace the text “pi” in the following command with the name of the user you want to use this for authentication.
6. With the SSH private key now saved and the permissions correctly set we can now proceed to login. We will do this before we disable password authentication, so we do not lock ourselves out of our Raspberry Pi.
For our SSH key authentication tutorial, we will be showing you how to connect to your Raspberry Pi using your private key and PuTTY.
Connecting using your Private Key on Linux
1. Utilizing the private key is dead easy on the Linux device that you generated the key in the first place.
The SSH tool by default on most Linux based systems is designed to automatically make use of the private key when attempting to make a connection.
As long as you are using the machine you used to generate the private key, you can use the SSH command as shown below.
The system will automatically try to use the private key that we created earlier to make the connection.
Thanks to copying the public key into the authorized_keys file of the remote host, it will be able to recognize our incoming private key and accept our connection.
2. If you set a passphrase, you will now be asked to enter that before you can continue, this is required to unlock your private key.
After entering your passphrase, you should now be logged into the remote machine.
If you don’t like having to enter your passphrase every time, don’t worry as we will go into how to cache this later on in the tutorial.
Connecting to your Raspberry Pi using a Private Key with PuTTY
1. In this section of the Raspberry Pi SSH keys tutorial, we will be showing you how to use your private key with PuTTY to connect to the Raspberry Pi.
Connecting using a private key is a relatively simple process.
Start by opening up PuTTY on your computer and entering your Raspberry Pi’s IP address (1.) then click on “Auth” under the “SSH” section (2.)
2. Next, you need to press the “Browse” button. This button will allow you to find and select the private key that we saved earlier in the tutorial. Selecting this file will allow PuTTY to try and use it for authentication.
After you have selected the private key from the browser, you should now press the “Open” button to start the connection.
3. Upon connecting you will be first asked to enter a username, Make sure this is the username that belongs to the private key that you are using otherwise authentication will fail.
After entering the correct username, you will be now asked to enter a passphrase for your private key if you set one earlier.
Upon entering a correct passphrase you will be logged into the SSH session. You can now proceed to disabling password authentication completely.
Removing Password Authentication
1. To disable password authentication, we need to modify the sshd_config file. Within this file, we can change the behavior of the SSH daemon.
To modify this file run the following command on your Raspberry Pi.
2. Within this file, we need to find the following line and change “yes” to “no“.
This simple change will completely disable the ability to login to your Raspberry Pi with just a password. From now on you will require the private key to gain access to the system through SSH.
If you are having trouble finding the line you can use CTRL + W to find it quickly. (If you’re using the nano editor)
Find
Replace with
3. You can now save and quit out of the file by pressing CTRL + X then Y and finally ENTER.
4. With the changes now made to the sshd_config file, we should restart our Raspberry Pi to ensure the changes are loaded in.
Putty Generate Ssh Private Key File
Remember to make sure that your private key is allowing you to connect to your Raspberry Pi as passwords won’t work after restarting.
Once you are happy with everything, use the following command on your Raspberry Pi to restart it.
5. If everything is working correctly you should only be able to perform an SSH connection if you have a valid private key.
Without the private key, the connection will be refused by the SSH agent. As you can no longer use your password, keeping your private key safe is a very crucial task as it is now your only way of remotely accessing your device.
If for some reason you manage to lose your private key or forget the passphrase for your private key there is still one way of gaining access to your device.
To fix any issues that may arise with your SSH connection you can still physically connect a keyboard and mouse to your device to regain control.
To restore password access over the SSH connection, you should try reverting the change we made to the PasswordAuthentication setting and then refollow the tutorial to set up the SSH keys again.
Caching SSH Passphrase for the Current Terminal Session
1. If you are using the SSH bash tool, then you can cache the passphrase for your private key while the current session is still going.
To do this, we must first start up another session of the ssh-agent. We can do this by running the following command within the terminal session.
Upon entering this command, you will be shown a process id for the ssh-agent that we just loaded. You can use this process id later on to kill the agent and remove the passphrase caching.
Putty Generate Ssh Private Key Extension
The process id should appear something like, “Agent pid 26484“, you need to make a note of the number.
2. Now that we have started up our additional session of the ssh-agent let’s go ahead and add our private key to it.
Putty Use Ssh Key
We can do this by just typing in the following command, be prepared to enter your private key’s passphrase.
3. With your SSH key now added to the agent, you should be able to login to any remote machine that has your key authorized without needing to enter your passphrase.
4. To remove your private key from the SSH-agent cache, you will need to kill the ssh-agent we started earlier.
The easiest way to do this is to make use of the process id that we grabbed earlier. Just insert that process id after the command ‘kill’ to kill the process.
I hope by the end of this Raspberry Pi SSH keys tutorial that you learned how to both generate and authenticate by using SSH keys. If you have any thoughts, tips or anything else that you would like to mention then please don’t hesitate to leave a comment below.