If you prefer to use a public key that is in a multiline format, you can generate an RFC formatted key in a pem container from the public key you previously created. Replace azureuser and myvm. If you provided a passphrase when you created your key pair, enter the passphrase when prompted during the sign-in process. 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.

To avoid typing your private key file passphrase with every SSH sign-in, you can use ssh-agent to cache your private key file passphrase. If you are using a Mac, the macOS Keychain securely stores the private key passphrase when you invoke ssh-agent. Verify and use ssh-agent and ssh-add to inform the SSH system about the key files so that you do not need to use the passphrase interactively.

The following example shows a simple configuration that you can use to quickly sign in as a user to a specific VM using the default SSH private key. You can add configurations for additional hosts to enable each to use its own dedicated key pair.

See SSH config file for more advanced configuration options. The first time you sign in to a server using an SSH key, the command prompts you for the passphrase for that key file. Azure VMs that are created with an SSH public key as the sign-in are better secured than VMs created with the default sign-in method, passwords. You need to use the ssh-keygen command as follows to generate RSA keys open terminal and type the following command : ssh-keygen -t rsa OR ssh-keygen Sample outputs:. The -t type option specifies the type of key to create.

Please do not share keys file with anyone else. You can upload keys to remote server as follows: ssh-copy-id [email protected] Finally, you can login to remote server as follows: ssh [email protected] scp file. Overview of SSH and keys SSH is an encrypted connection protocol that allows secure sign-ins over unsecured connections.

Private key passphrase The SSH private key should have a very secure passphrase to safeguard it. Generate keys automatically during deployment If you use the Azure CLI to create your VM, you can optionally generate SSH public and private key files by running the az vm create command with the --generate-ssh-keys option.

Use ssh-agent to store your private key passphrase To avoid typing your private key file passphrase with every SSH sign-in, you can use ssh-agent to cache your private key file passphrase. Now add the private key to ssh-agent using the command ssh-add.

The private key passphrase is now stored in ssh-agent. If you are already running an Ubuntu If you are configuring your server for the first time, you may not have SSH installed. This will create a hidden directory to store your SSH keys, and modify the permissions for that directory. The ssh-keygen command creates a bit RSA key pair. The system will ask you to create a passphrase as an added layer of security. Input a memorable passphrase, and press Enter. This process creates two keys.

The other one is a private key, which you will need to keep secure. The secure private key ensures that you are the only person who can encrypt the data that is decrypted by the public key.

On the client system, use the ssh-copy-id command to copy the identity information to the Ubuntu server :. Then it will prompt you to enter the password for the server user account. If your system does not have the ssh-copy-id command, you can copy the key manually over the SSH.

The system should not ask for a password as it is negotiating a secure connection using the SSH keys. If you used a security passphrase, you would be prompted to enter it. After you do so, you are logged in.

In the default configuration, OpenSSH allows any user to configure new keys. The keys are permanent access credentials that remain valid even after the user's account has been deleted. In organizations with more than a few dozen users, SSH keys easily accumulate on servers and service accounts over the years. We have seen enterprises with several million keys granting access to their production servers. It only takes one leaked, stolen, or misconfigured key to gain access.

In any larger organization, use of SSH key management solutions is almost necessary. SSH keys should also be moved to root-owned locations with proper provisioning and termination processes. For more information, see how to manage SSH keys.

Practically all cybersecurity regulatory frameworks require managing who can access what. SSH keys grant access, and fall under this requirement. This, organizations under compliance mandates are required to implement proper management processes for the keys.

It is important to ensure there is enough unpredictable entropy in the system when SSH keys are generated. There have been incidents when thousands of devices on the Internet have shared the same host key when they were improperly configured to generate the key without proper randomness.

On general purpose computers, randomness for SSH key generation is usually not a problem. It may be something of an issue when initially installing the SSH server and generating host keys, and only people building new Linux distributions or SSH installation packages generally need to worry about it.

Our recommendation is to collect randomness during the whole installation of the operating system, save that randomness in a random seed file. Then boot the system, collect some more randomness during the boot, mix in the saved randomness from the seed file, and only then generate the host keys.

This maximizes the use of the available randomness. And make sure the random seed file is periodically updated, in particular make sure that it is updated after generating the SSH host keys. Many modern general-purpose CPUs also have hardware random number generators. This helps a lot with this problem.

The best practice is to collect some entropy in other ways, still keep it in a random seed file, and mix in some entropy from the hardware random number generator. This way, even if one of them is compromised somehow, the other source of randomness should keep the keys secure.

Available entropy can be a real problem on small IoT devices that don't have much other activity on the system. They may just not have the mechanical randomness from disk drive mechanical movement timings, user-caused interrupts, or network traffic. Furthermore, embedded devices often run on low-end processors that may not have a hardware random number generator. Our recommendation is that such devices should have a hardware random number generator. If the CPU does not have one, it should be built onto the motherboard.

The cost is rather small. The regulations that govern the use case for SSH may require a specific key length to be used. In general, bits is considered to be sufficient for RSA keys. This only listed the most commonly used options. For full usage, including the more exotic and special-purpose options, use the man ssh-keygen command.