1. Symmetric Key
2. Install Ssh Public Key Linux
3. Linux Ssh Generate Public Key From Private Key
4. Linux Generate Public Key

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Description (how to do it): Generate a key/pair or use an existing private key: If you have a private key: Open puttygen. Create a new 'authorizedkeys' file (with Notepad): Copy your public key data from. Upload the key to a Linux server. Set proper permissions: Make a.ssh. This will create a private key written to /home/youruser/.ssh/ idrsa and a public key written to /home/youruser/.ssh/ idrsa.pub. To use the keys with your SiteGround account, you need to upload the public key in cPanel, under SSH/Shell access. The private key needs to be loaded in your Terminal using the ssh-add command: 1. Apr 14, 2020  It is kind of a pain to have to enter your username and password every time you push or pull from github. There is a solution. We will use an ssh public key to authenticate your identity. In this method of authentication you generate a public key and a private key. 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. 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.

You can generate an SSH key pair directly in cPanel, or you can generate the keys yourself and just upload the public one in cPanel to use with your hosting account. When generating SSH keys yourself under Linux, you can use the ssh-keygen command. Jul 21, 2018  How to create SSH public key from SSH private key to enable SSH keybased authentication in Linux and Vagrant. Though SSH private key is enough to enable SSH key based authentication, Sometimes it is necessary to create SSH public key from private key. This post covers how to convert SSH public key to SSH Private key.

Password authentication is the default method most SSH (Secure Shell) clients use to authenticate with remote servers, but it suffers from potential security vulnerabilities, like brute-force login attempts. An alternative to password authentication is public key authentication, in which you generate and store on your computer a pair of cryptographic keys and then configure your server to recognize and accept your keys. Using key-based authentication offers a range of benefits:

• Key-based login is not a major target for brute-force hacking attacks.

• If a server that uses SSH keys is compromised by a hacker, no authorization credentials are at risk of being exposed.

• Because a password isn’t required at login, you are able to able to log in to servers from within scripts or automation tools that you need to run unattended. For example, you can set up periodic updates for your servers with a configuration management tool like Ansible, and you can run those updates without having to be physically present.

This guide will explain how the SSH key login scheme works, how to generate an SSH key, and how to use those keys with your Linode.

How SSH Keys Work

SSH keys are generated in pairs and stored in plain-text files. The key pair (or keypair) consists of two parts:

• A private key, usually named id_rsa. The private key is stored on your local computer and should be kept secure, with permissions set so that no other users on your computer can read the file.

  Caution

• A public key, usually named id_rsa.pub. The public key is placed on the server you intend to log in to. You can freely share your public key with others. If someone else adds your public key to their server, you will be able to log in to that server.

When a site or service asks for your SSH key, they are referring to your SSH public key (id_rsa.pub). For instance, services like GitHub and Gitlab allow you to place your SSH public key on their servers to streamline the process of pushing code changes to remote repositories.

The authorized_keys File

In order for your Linode to recognize and accept your key pair, you will need to upload your public key to your server. More specifically, you will need to upload your public key to the home directory of the user you would like to log in as. If you would like to log in to more than one user on the server using your key pair, you will need to add your public key to each of those users.

To set up SSH key authentication for one of your server’s users, add your public key to a new line inside the user’s authorized_keys file. This file is stored inside a directory named .ssh/ under the user’s home folder. A user’s authorized_keys file can store more than one public key, and each public key is listed on its own line. If your file contains more than one public key, then the owner of each key listed will be able to log in as that user.

Granting Someone Else Access to your Server

To give someone else access to your server’s user, simply add their public key on a new line in your authorized_keys file, just as you would add your own. To revoke access for that person, remove that same line and save the changes.

Challenge-Response

When logging in to a server using SSH, if there is a public key on file on that server, the server will create a challenge. This challenge will be crafted in such a way that only the holder of the private SSH key will be able to decipher it.

This challenge-response action happens without any user interaction. If the person attempting to log in has the corresponding private key, then they will be safely logged in. If not, the login will either fail or fall back to a password-based authentication scheme.

SSH Key Passphrases

Symmetric Key

You can optionally provide an additional level of security for your SSH keys by encrypting them with a passphrase at the time of creation. When you attempt to log in using an encrypted SSH key, you will be prompted to enter its passphrase. This is not to be confused with a password, as this passphrase only decrypts the key file locally and is not transferred over the Internet as a password might be.

If you’d like to set up your logins so that they require no user input, then creating a passphrase might not be desirable, but it is strongly recommended nevertheless.

Linux and macOS

Generate a Key Pair

Perform the steps in this section on your local machine.

1. Create a new key pair.

   Caution

   This command will overwrite an existing RSA key pair, potentially locking you out of other systems.

   If you’ve already created a key pair, skip this step. To check for existing keys, run ls ~/.ssh/id_rsa*.

   If you accidentally lock yourself out of the SSH service on your Linode, you can still use the Lish console to login to your server. After you’ve logged in via Lish, update your authorized_keys file to use your new public key. This should re-establish normal SSH access.

   Street fighter x tekken product key generator download free. The -b flag instructs ssh-keygen to increase the number of bits used to generate the key pair, and is suggested for additional security.

2. Press Enter to use the default names id_rsa and id_rsa.pub in the /home/your_username/.ssh directory before entering your passphrase.

3. While creating the key pair, you will be given the option to encrypt the private key with a passphrase. This means that the key pair cannot be used without entering the passphrase (unless you save that passphrase to your local machine’s keychain manager). We suggest that you use the key pair with a passphrase, but you can leave this field blank if you don’t want to use one.

Upload your Public Key

There are a few different ways to upload your public key to your Linode from Linux and macOS client systems:

Using ssh-copy-id

ssh-copy-id is a utility available on some operating systems that can copy a SSH public key to a remote server over SSH.

1. To use ssh-copy-id, pass your username and the IP address of the server you would like to access:

2. You’ll see output like the following, and a prompt to enter your user’s password:

3. Verify that you can log in to the server with your key.

Using Secure Copy (scp)

Secure Copy (scp) is a tool that copies files from a local computer to a remote server over SSH:

1. Connect to your server via SSH with the user you would like to add your key to:

2. Create the ~/.ssh directory and authorized_keys file if they don’t already exist:

3. Give the ~/.ssh directory and authorized_keys files appropriate file permissions:

4. In another terminal on your local machine, use scp to copy the contents of your SSH public key (id_rsa.pub) into the authorized_keys file on your server. Substitute in your own username and your server’s IP address:

5. Verify that you can log in to the server with your key.

Manually Copy an SSH Key

You can also manually add an SSH key to a server:

1. Begin by copying the contents of your public SSH key on your local computer. You can use the following command to output the contents of the file:

   You should see output similar to the following:

   Note that the public key begins with ssh-rsa and ends with [email protected].

2. Once you have copied that text, connect to your server via SSH with the user you would like to add your key to:

3. Create the ~/.ssh directory and authorized_keys file if they don’t already exist:

4. Give the ~/.ssh directory and authorized_keys files appropriate file permissions:

5. Open the authorized_keys file with the text editor of your choice (nano, for example). Then, paste the contents of your public key that you copied in step one on a new line at the end of the file.

6. Save and close the file.

   Note

   If you initially logged into the server as root but edited the authorized_keys file of another user, then the .ssh/ folder and authorized_keys file of that user may be owned by root. Set that other user as the files’ owner:

7. Verify that you can log in to the server with your key.

Connect to the Remote Server

1. SSH into the server from your local machine:

2. If you chose to use a passphrase when creating your SSH key, you will be prompted to enter it when you attempt to log in. Depending on your desktop environment, a window may appear:

   Caution

   Do not allow the local machine to remember the passphrase in its keychain unless you are on a private computer which you trust.

   You may also see the passphrase prompt at your command line:

3. Enter your password. You should see the connection establish in the local terminal.

Windows

Install Ssh Public Key Linux

The following instructions use the PuTTY software to connect over SSH, but other options are available on Windows too.

Generate a Key Pair with PuTTY

1. Download PuTTYgen (puttygen.exe) and PuTTY (putty.exe) from the official site.

2. Launch puttygen.exe. The RSA key type at the bottom of the window is selected by default for an RSA key pair but ED25519 (EdDSA using Curve25519) is a comparable option if your remote machine’s SSH server supports DSA signatures. Do not use the SSH-1(RSA) key type unless you know what you’re doing.

3. Increase the RSA key size from 2048 bits 4096 and click Generate:

4. PuTTY uses the random input from your mouse to generate a unique key. Once key generation begins, keep moving your mouse until the progress bar is filled:

5. When finished, PuTTY will display the new public key. Right-click on it and select Select All, then copy the public key into a Notepad file.

6. Save the public key as a .txt file or some other plaintext format. This is important–a rich text format such as .rtf or .doc can add extra formatting characters and then your private key won’t work:

7. Enter a passphrase for the private key in the Key passphrase and Confirm passphrase text fields. Important: Make a note of your passphrase, you’ll need it later:

8. Click Save private key. Choose a file name and location in Explorer while keeping the ppk file extension. If you plan to create multiple key pairs for different servers, be sure to give them different names so that you don’t overwrite old keys with new:

Manually Copy the SSH Key with PuTTY

1. Launch putty.exe. Find the Connection tree in the Category window, expand SSH and select Auth. Click Browse and navigate to the private key you created above:

2. Scroll back to the top of the Category window and click Session. Enter the hostname or IP address of your Linode. PuTTY’s default TCP port is 22, the IANA assigned port for for SSH traffic. Change it if your server is listening on a different port. Name the session in the Saved Sessions text bar and click Save:

3. Click the Open button to establish a connection. You will be prompted to enter a login name and password for the remote server.

4. Once you’re logged in to the remote server, configure it to authenticate with your SSH key pair instead of a user’s password. Create an .ssh directory in your home directory on your Linode, create a blank authorized_keys file inside, and set their access permissions:

5. Open the authorized_keys file with the text editor of your choice (nano, for example). Then, paste the contents of your public key that you copied in step one on a new line at the end of the file.

6. Save, close the file, and exit PuTTY.

7. Verify that you can log in to the server with your key.

Using WinSCP

Uploading a public key from Windows can also be done using WinSCP:

1. In the login window, enter your Linode’s public IP address as the hostname, the user you would like to add your key to, and your user’s password. Click Login to connect.

2. Once connected, WinSCP will show two file tree sections. The left shows files on your local computer and the right shows files on your Linode. Using the file explorer on the left, navigate to the file where you saved your public key in Windows. Select the public key file and click Upload in the toolbar above.

3. You’ll be prompted to enter a path on your Linode where you want to upload the file. Upload the file to /home/your_username/.ssh/authorized_keys.

4. Verify that you can log in to the server with your key.

Connect to the Remote Server with PuTTY

Start PuTTY and Load your saved session. You’ll be prompted to enter your server user’s login name as before. However, this time you will be prompted for your private SSH key’s passphrase rather than the password for your server’s user. Enter the passphrase and press Enter.

Troubleshooting

If your SSH connections are not working as expected, or if you have locked yourself out of your system, review the Troubleshooting SSH guide for troubleshooting help.

Upload your SSH Key to the Cloud Manager

It is possible to provision each new Linode you create with an SSH public key automatically through the Cloud Manager.

1. Log in to the Cloud Manager.

2. Click on your username at the top right hand side of the page. Then click on My Profile in the dropdown menu that appears:

   Note

   If you are viewing the Cloud Manager in a smaller browser window or on a smaller device, then the My Profile link will appear in the sidebar links. To view the sidebar links, click on the disclosure button to the left of the blue Create button at the top of the page.

3. From the My Profile page, select the SSH Keys tab, and then click Add a SSH Key:

4. Create a label for your key, then paste in the contents of your public SSH key (id_rsa.pub):

5. Click Add Key.

6. When you next create a Linode you’ll be given the opportunity to include your SSH key in the Linode’s creation. This key will be added to the root user of the new Linode.

   In the Create Linode form, select the SSH key you’d like to include. This field will appear below the Root Password field:

Next Steps

After you set up your SSH keys and confirm they are working as expected, review the How to Secure Your Server guide for instructions on disabling password authentication for your server.

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This guide is published under a CC BY-ND 4.0 license.

Connect to a server by using SSH on Linux or Mac OS X

This article provides steps for connecting to a cloud server froma computer running Linux® or MacOS® X by using Secure Shell (SSH).It also discusses generating an SSH key and adding a public key tothe server.

Introduction

SSH is a protocol through which you can access your cloud server and runshell commands. You can use SSH keys to identify trusted computers withoutthe need for passwords and to interact with your servers.

SSH is encrypted with Secure Sockets Layer (SSL), which makes it difficultfor these communications to be intercepted and read.

Note: Many of the commands in this article must be run on your localcomputer. The default commands listed are for the Linux command line orMacOS X Terminal. To make SSH connections from Windows®, you can use a clientsimilar to the free program, PuTTY.To generate keys, you can use a related program, PuTTYGen.

Log in

Using the Internet Protocol (IP) address and password for your cloud server, log in byrunning the following ssh command with username@ipaddress as the argument:

The system prompts you to enter the password for the account to which you’reconnecting.

Remote host identification

If you rebuilt your cloud server, you might get the following message:

One of the security features of SSH is that when you log in to a cloudserver, the remote host has its own key that identifies it. When you tryto connect, your SSH client checks the server’s key against any keysthat it has saved from previous connections to that IP address. After yourebuild a cloud server, that remote host key changes, so your computerwarns you of possibly suspicious activity.

To ensure the security of your server, you canuse the web console in the Cloud Control Panel to verify your server’s new key.If you’re confident that you aren’t being spoofed, you can skip thatstep and delete the record of the old SSH host key as follows:

On your local computer, edit the SSH known_hosts file and remove anylines that start with your cloud server’s IP address.

Note: Use the editor of your choice, such as nano on Debian or theUbuntu operating systemor vi on RPM or CENTOS servers. For simplicity, this article just uses nano. If you prefer to use vi,substitute vi for nano in the edit commands.For more on using nano, seehttps://support.rackspace.com/how-to/modify-your-hosts-file/.

If you are not using Linux or MacOS X on your local computer, thelocation of the known_hosts file might differ. Refer to your OS forinformation about the file location. PuTTY on Windows gives you theoption to replace the saved host key.

Generate a new SSH key pair

You can secure SSH access to your cloud server against brute forcepassword attacks by using a public-private key pair. A public key is placed onthe server and a matching private key is placed on your local computer. If youconfigure SSH on your server to accept only connections using keys,then no one can log in by using just a password. Connecting clientsare required to use a private key that has a public key registered onthe server. For more on security, reviewLinux server security best practices.

Use the following steps to generate an SSH key pair:

1. Run the following command using your email address as a label.Substitute your email address for your_email@example.com inthe command.

   A message indicates that your public-private RSA key pair isbeing generated.

   At the prompt, press Enter to use the default location or entera file in which to save the key and press Enter.

2. If you want the additional security of a password for the key pair,enter a passphraseand press Enter. If you don’t want to use a passwordwith the key pair, press Enter to continue without setting one.

   Your key pair is generated, and the output looks similar to the following example:

3. Optionally, add your new key to the local ssh-agent file to enableSSH to find your key without the need to specify its location everytime that you connect:

   You can use an SSH configuration shortcut instead of the ssh-agent fileby following the instructions in the Shortcut configuration sectionlater in this article.

Add the public key to your cloud account

To make it easy to add your key to new cloud servers that you create,upload the public key to your cloud account by following these steps:

1. Log in to the Cloud Control Panel.
2. In the top navigation bar, click Select a Product > Rackspace Cloud.
3. Select Servers > SSH Keys.
4. Click Add Public Key.
5. Enter a key name, such as Work Laptop, to remind you which computer this key is for.
6. Select the region for which you want to store the public key. Tostore your key in multiple regions, repeat these steps foreach region. The key must reside in the same region as the server.

7. Paste the contents of the id_rsa.pub file that you created intothe Public Key field. You can get the file contents by eitheropening the file in a text editor or by running the followingcommand:

8. Click Add Public Key.

If you want to add the key manually, instead of by using the Control Panel, reviewLinux server security best practicesand use the following command:

Create a new server by using a stored key

When you create a new cloud server, you can add a stored key to the newserver.

1. On the Create Server page, expand the Advanced Options section.

2. From the SSH Key menu, select your key from the list.

3. If you don’t see a stored key in the list, you can perform one of the following actions:

   • Switch the region for the new server to the region where you have stored the SSH key.
   • Repeat the steps in the preceding section, Add the public key to your cloud account,to add the key to the region in which you want to create the new server.

Add the key to an existing server

You can’t use the Cloud Control Panel to add a public key to anexisting server. Follow these steps to add the key manually:

1. On your cloud server, create a directory named .ssh in the homefolder of the user that you connect to by using SSH.

2. Create or edit the authorized_keys file and add your public key tothe list of authorized keys by using the following command:

   A key is all on one line, so ensure that the key isn’t broken byline breaks. You can have multiple keys in the authorized_keysfile, with one key per line.

3. Set the correct permissions on the key by using the following commands:

4. If you have any issues and need to fix permissions issues, run the following comand:

After you have added the public key to the authorized_keys, you can make an SSHconnection by using your key pair instead of the account password.

Shortcut configuration

Use the following instructions to set up a connection shortcut by creating a~/.ssh/config file on your local computer and adding your server and keydetails to it.

1. Using a text editor, add the following text to the ~/.ssh/config file, changing thevalues to match your server information:

   Each of the following entries describes a feature of the server:

   • Host: A shortcut name that you use to tell SSH to use thisconnection.
   • HostName: The address of the server to which you connect.
   • User: The name of the user account to connect to on theserver.
   • IdentityFile: The location of the private key file (id_rsa).

2. After you set up the config file, connect to the server by usingthe following command with your shortcut name:

Troubleshooting

If you have trouble making a new connection after you restart theserver, use the following steps to help you resolve the issue:

• The best way to troubleshoot SSH or SFTP login issues is to attempt tologin through SSH while logged into the Emergency Console and to watch the log,which typically includes the reason for a failure. If no reason is given,it could be a firewall issue. For RPM servers, run the following command to watch the log:

  For Debian servers, run the following command to watch the log:

• If you get a connection timeout error, check the IP address thatyou used to ensure that it’s correct. You might also check theserver’s iptables to ensure that it isn’t blocking the port used by SSH.
• If you get a connection refused error, you might be trying to useSSH with the wrong port. If you changed your server to listen to aport other than 22, use the -p option with SSH to specifythe port.
• If your login is rejected, then you might have an issuewith your key. Change the sshd configuration to allow passwordconnections by setting PasswordAuthentication to yes. Restartthe server and try again. If you connect after these changes, thenthe issue is with the key and you must verify that the key is in theright place on the server.

• If all else fails, review your changes and restart the SSH daemon onthe server by running the following command:

  If you get a message that the SSH service is unknown, run thecommand with sshd as the service name instead.

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Linux Ssh Generate Public Key From Private Key

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Linux Generate Public Key

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