Generate RSA keys with SSH by using PuTTYgen

Aug 19, 2019  1. Start by logging into the source machine (local server) and creating a 2048-bit RSA key pair using the command. Ssh-keygen -t rsa. If you want to tighten up security measures, you can create a 4096-bit key by adding the -b 4096 flag. Ssh-keygen -t rsa -b 4096. Dec 01, 2017  ssh-keygen can create RSA keys for use by SSH protocol version 1 and DSA, ECDSA or RSA keys for use by SSH protocol version 2. The type of key to be generated is specified with the -t option. If invoked without any arguments, ssh-keygen will generate an RSA key for use in SSH. New keys with OpenSSH private key format can be converted using ssh-keygen utility to the old PEM format. Ssh-keygen -p -m PEM -f /.ssh/idrsa There is no need to downgrade to older OpenSSH just to achieve this result. To create a new key pair, select the type of key to generate from the bottom of the screen (using SSH-2 RSA with 2048 bit key size is good for most people; another good well-known alternative is ECDSA).

Apr 02, 2019  In case the -o option does not work on your server (it has been introduced in 2014) or you need a private key in the old PEM format, then use the command 'ssh-keygen -b 4096 -t rsa'. The -b option of the ssh-keygen command is used to set the key length to 4096 bit instead of the default 1024 bit for security reasons. Specifies the number of bits in the private key to create. For RSA keys, the minimum size is 1024 bits and the default is 4096 bits. Generally, 2048 bits is considered sufficient.

One effective way of securing SSH access to your cloud server is to usea public-private key pair. This means that a public key is placed onthe server and a private key is placed on your local workstation.Using a key pair makes it impossible for someone to log in by using justa password, as long as you set up SSH to deny password-basedauthentication.

This article provides steps for generating RSA keys by using PuTTYgen onWindows for secure SSH authentication with OpenSSH.

4096

Generate keys

In Windows, use PuTTYgen to generate your public and private keys.

  1. If needed, download PuTTYgen from the PuTTY download page.(PuTTYgen might have been installed previously with PuTTY or WinSCP.)
  2. Launch the program, and then click the Generate button.The program generates the keys for you.
  3. Enter a unique key passphrase in the Key passphrase andConfirm passphrase fields.For additional information about using passphrases,see Log in with a SSH Private Key on Windows.
  4. Save the public and private keys by clicking the Save public keyand Save private key buttons.
  5. From the Public key for pasting into OpenSSH authorized_keys filefield at the top of the window, copy all the text (starting with ssh-rsa)to your clipboard by pressing Ctrl-C.You need this key available on your clipboard to paste eitherinto the public key tool in the Control Panel or directly into theauthorized keys on your cloud server.

Use the key pair

You can use the RSA key pair in the following ways.

Specify your SSH key when creating a new cloud server

When you create a cloud server, you can assign a public key from the list of keys.If your key is not already in the list, you may add it, and then assign it.

Add a new public key to the list

  1. Under Advanced Options on the Create Server page, click Manage SSHKeys.
  2. Select public key for the cloud server from the SSH Keys listand click Add Public Key.
  3. Enter the key name, select the region, and paste the entire publickey into the Public Key field. Then click Add Public Key.
  4. Go back to the Create Server page, and confirm that your key is listedin the SSH Key list.

Assign a public key

  1. Under Advanced Options on the Create Server page, select the publickey you want to use from the SSH key drop-down menu.
  2. When you are done specifying the all the other details for the server,click Create Server.

Assign your SSH Key to an existing cloud server

To make use of your newly generated RSA key pair, you must tell PuTTY touse it when connecting to your cloud server.

  1. To edit the file (or create it), run the following command on the cloud server:

  2. Paste the text onto its own line in the file.

    You must have the key available in your clipboard to paste it. The key and itsassociated text (the ssh-rsa identified at the start and the comment at the end)must be on one line in the file. If the text is word-wrapped onto multiple linesan error might occur when connecting.

  3. If you created the authorized_keys file, change its permissionsafter you’re done editing it by running the following command:

  4. Open PuTTY, and go to the SSH > Auth section.

  5. Browse to the location of the key file, and load the private key.

    Generate private key from bitcoin address generator. It is a decentralized digital currency without a central bank or single administrator that can be sent digitally from user-to-user on the peer-to-peer Bitcoin network without the need for intermediaries.A Bitcoin Address is an ID of 26-35 alphanumeric numbers, that represents a possible destination for an (incoming) Bitcoin payment for example to a Bitcoin Wallet. What is Bitcoin?Bitcoin is a cryptocurrency, a form of electronic cash. A Bitcoin wallet address, which is a hash of the corresponding public key, always starts either with number 1 or with the number 3.

  6. Go to the Session page, and save the session. This saves the configurationso that PuTTY uses the key every time that you connect to your cloudserver.

After you save your session, your key is loaded automatically when youconnect to your server.

Related article

Ssh generate private key 4096 file

Experience what Rackspace has to offer.

©2020 Rackspace US, Inc.

Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License

This version of GitHub Enterprise will be discontinued on This version of GitHub Enterprise was discontinued on 2019-03-27. No patch releases will be made, even for critical security issues. For better performance, improved security, and new features, upgrade to the latest version of GitHub Enterprise.For help with the upgrade, contact GitHub Enterprise support.

After you've checked for existing SSH keys, you can generate a new SSH key to use for authentication, then add it to the ssh-agent.

If you don't already have an SSH key, you must generate a new SSH key. If you're unsure whether you already have an SSH key, check for existing keys.

If you don't want to reenter your passphrase every time you use your SSH key, you can add your key to the SSH agent, which manages your SSH keys and remembers your passphrase.

Generating a new SSH key

Private Key Definition

  1. Open TerminalTerminalGit Bashthe terminal.

  2. Paste the text below, substituting in your GitHub Enterprise email address.

    This creates a new ssh key, using the provided email as a label.

  3. When you're prompted to 'Enter a file in which to save the key,' press Enter. This accepts the default file location.

  4. At the prompt, type a secure passphrase. For more information, see 'Working with SSH key passphrases'.

Create Ssh Key 4096

Adding your SSH key to the ssh-agent

Before adding a new SSH key to the ssh-agent to manage your keys, you should have checked for existing SSH keys and generated a new SSH key. When adding your SSH key to the agent, use the default macOS ssh-add command, and not an application installed by macports, homebrew, or some other external source.

  1. Start the ssh-agent in the background.

  2. If you're using macOS Sierra 10.12.2 or later, you will need to modify your ~/.ssh/config file to automatically load keys into the ssh-agent and store passphrases in your keychain.

  3. Add your SSH private key to the ssh-agent and store your passphrase in the keychain. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_rsa in the command with the name of your private key file.

    Note: The -K option is Apple's standard version of ssh-add, which stores the passphrase in your keychain for you when you add an ssh key to the ssh-agent.

    If you don't have Apple's standard version installed, you may receive an error. For more information on resolving this error, see 'Error: ssh-add: illegal option -- K.'

  4. Add the SSH key to your GitHub account.

If you have GitHub Desktop installed, you can use it to clone repositories and not deal with SSH keys. It also comes with the Git Bash tool, which is the preferred way of running git commands on Windows.

  1. Ensure the ssh-agent is running:

    • If you are using the Git Shell that's installed with GitHub Desktop, the ssh-agent should be running.

    • If you are using another terminal prompt, such as Git for Windows, you can use the 'Auto-launching the ssh-agent' instructions in 'Working with SSH key passphrases', or start it manually:

  2. Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_rsa in the command with the name of your private key file.

  3. Add the SSH key to your GitHub account.

  1. Start the ssh-agent in the background.

  2. Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_rsa in the command with the name of your private key file.

  3. Add the SSH key to your GitHub account.

  1. Start the ssh-agent in the background.

  2. Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_rsa in the command with the name of your private key file.

  3. Add the SSH key to your GitHub account.

Further reading

  • 'About SSH'
  • 'Working with SSH key passphrases'