How to Copy SSH Keys

Introduction

SSH (Secure Shell) is a protocol used to securely log into remote systems. SSH uses encryption to protect the authentication process and data transfer. One of the most common ways to access remote systems using SSH is to use an SSH key pair, which consists of a private key and a public key. In this article, we will explain how to copy SSH keys from one system to another, which is an important step in setting up a secure connection.

Generating an SSH Key Pair

If you don’t have an existing SSH key pair, you’ll need to generate a new one. To generate an SSH key pair, open a terminal window on your local system and type the following command:

ssh-keygen -t rsa

This will start the key generation process, and you’ll be prompted to specify the location to save the key pair. By default, the keys are saved in the ~/.ssh directory. You can press enter to accept the default location or specify a different one.

Next, you’ll be prompted to enter a passphrase. A passphrase is an optional extra layer of security that protects your private key. If you don’t want to use a passphrase, just press enter.

Once the key pair has been generated, you’ll see output similar to the following:


Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
01:0f:f4:3b:ca:85:d6:17:a1:7d:f0:68:9d:f0:a2:db [email protected]


Copying the Public Key

The next step is to copy the public key to the remote system. The easiest way to do this is to use the ssh-copy-id command, which is included with most SSH implementations. To use ssh-copy-id, run the following command on your local system, replacing <user> and <remote_system> with the appropriate values:

ssh-copy-id user@remote_system

You’ll be prompted to enter your password for the remote system. Once you’ve entered your password, the public key will be added to the ~/.ssh/authorized_keys file on the remote system.

Testing the Connection

Now that the public key has been added to the remote system, you can test the connection. To do this, run the following command on your local system, replacing <user> and <remote_system> with the appropriate values:

ssh user@remote
_system

If the connection was successful, you should be logged into the remote system without being prompted for a password. If you specified a passphrase when generating the key pair, you’ll be prompted to enter the passphrase before logging into the remote system.

If the connection was not successful, make sure that the public key has been added to the correct file on the remote system, and that the file has the correct permissions. The ~/.ssh/authorized_keys file should be owned by the user that you’re logging in as, and should have permissions of 600.

Copying the Private Key

If you need to copy the private key to another system, it’s important to keep the private key secure. The private key should never be shared with anyone, and should only be stored on systems that you trust. To copy the private key, you can either use a secure file transfer method, such as scp or sftp, or you can copy and paste the contents of the private key file from one system to another.

To copy the private key using scp, run the following command on your local system, replacing <user>, <private_key_file>, and <remote_system> with the appropriate values:

scp <private_key_file> user@remote_system:~/.ssh/

To copy the private key using sftp, you’ll need to use an SFTP client, such as FileZilla. Connect to the remote system using the appropriate credentials, navigate to the ~/.ssh/ directory, and upload the private key file.

If you choose to copy and paste the contents of the private key file, be sure to copy the entire contents of the file, including any leading or trailing whitespace. You can view the contents of the private key file using a text editor, such as nano or vim.

Conclusion

Copying SSH keys is an important step in setting up a secure connection to a remote system. By following the steps outlined in this article, you can easily copy your SSH keys and establish a secure connection to the remote system. Whether you’re copying the public key to the remote system, or the private key to another system, it’s important to keep the keys secure to ensure the security of your connection.

By using SSH keys, you can log into remote systems securely, without having to enter a password every time. This makes it easier and more convenient to manage remote systems, and also helps to protect against unauthorized access. Whether you’re a system administrator, a developer, or a power user, using SSH keys is an essential part of working with remote systems.

Additionally, SSH keys offer the added benefit of increased security. Because they use public-key cryptography, they provide a higher level of security than traditional password-based authentication methods. With password-based authentication, a password is sent over the network in clear text, making it susceptible to eavesdropping. With SSH keys, the private key is never transmitted over the network, reducing the risk of unauthorized access.

It’s also worth mentioning that SSH keys are not limited to just copying files. SSH keys can be used for a variety of other purposes, such as automating tasks, forwarding X11 traffic, and running commands on a remote system.

In conclusion, if you’re working with remote systems, using SSH keys is a must. They offer a secure, convenient, and efficient way to manage remote systems, and can save you time and effort in the long run. Whether you’re copying the public key to the remote system or the private key to another system, make sure to follow the steps outlined in this article to ensure the security of your connection.