Puttygen Generate Ssh Key Windows

An SSH Key allows you to log into your server without needing a password. SSH Keys can be automatically added to servers during the installation process. Creating an SSH key on Windows. The simplest way to create SSH key on Windows is to use PuTTYgen. Download and run PuTTYgen. Click the 'Generate' button. With both Tectia SSH and OpenSSH servers, access to an account is configured by generating a public key, copying the public key to the server, and adding the public key to a /.ssh/authorizedkeys file. To extract the public key, use: puttygen -L keyfile.ppk.

  • Jul 19, 2013  However, PuTTY does have a companion named PuTTYgen (an RSA and DSA key generation utility), that can convert OpenSSH private key files into PuTTY's format; allowing you to connect to your cloud server from a Windows machine, with the added security that SSH keys provide. PuTTYgen is what you will use to generate your SSH keys for use in.
  • PuTTYgen is used to generate public or private key pair for creating SSH keys. Below is the complete guidance about how to generate RSA key in Windows operating system: Once you install the PuTTY on your machine, you can easily run PuTTYgen. For the same, go to Windows - Start Menu - All Programs - PuTTY - PuTTYgen.
  • Key generation with PuTTY. To generate a key pair with the PuTTY key generator, simply run puttygen.exe and click the Generate button in the window that appears. You will be asked to move the mouse and press keys to improve the random number generation at the heart of SSH security.

Obtaining and Starting PuTTYgen

PuTTYgen originates from PuTTY and is also part of the PuTTY installation package. It can be downloaded here: https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

When you run PuTTYgen you will see a window where you have two choices: Generate, to generate a new public/private key pair, or Load to load in an existing private key.

Generating a New Key

  • First, you need to select which type of key you want to generate, and also select the strength of the key.
  • Then press the Generate button, to actually generate the key.
  • Once you have generated the key, select a comment field and a passphrase.
  • Now you’re ready to save the private key to disk; press the Save private key button.

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Your key pair is now ready for use. You may also want to copy the public key to your server, either by copying it out of the Public key for pasting into authorized_keys file box, or by using the Save public key button. However, you don’t need to do this immediately; if you want, you can load the private key back into PuTTYgen later and the public key will be available for copying and pasting again.

Selecting the Type of Key

Before generating a key pair using PuTTYgen, you need to select which type of key you need. PuTTYgen currently supports these types of key:

  • An RSA key for use with the SSH-2 protocol.
  • A DSA key for use with the SSH-2 protocol.
  • An ECDSA (elliptic curve DSA) key for use with the SSH-2 protocol.
  • An Ed25519 key (another elliptic curve algorithm) for use with the SSH-2 protocol.
  • An RSA key for use with the SSH-1 protocol.

The SSH-2 protocol supports more than one key type. The types supported by WinSCP are RSA, DSA, ECDSA, and Ed25519.

The SSH-1 protocol only supports RSA keys; if you will be connecting using the SSH-1 protocol, you must select the last key type or your key will be completely useless.

Puttygen Generate Ssh Key Windows

Selecting the Size (Strength) of the Key


The Number of bits input box allows you to choose the strength of the key PuTTYgen will generate.

For RSA, 2048 bits should currently be sufficient for most purposes.

For ECDSA, only 256, 384, and 521 bits are supported. (ECDSA offers equivalent security to RSA with smaller key sizes.)

For Ed25519, the only valid size is 256 bits.

The Generate Button

Once you have chosen the type of key you want, and the strength of the key, press the Generate button and PuTTYgen will begin the process of actually generating the key.

First, a progress bar will appear and PuTTYgen will ask you to move the mouse around to generate randomness. Wave the mouse in circles over the blank area in the PuTTYgen window, and the progress bar will gradually fill up as PuTTYgen collects enough randomness. You don’t need to wave the mouse in particularly imaginative patterns (although it can’t hurt); PuTTYgen will collect enough randomness just from the fine detail of exactly how far the mouse has moved each time Windows samples its position.

When the progress bar reaches the end, PuTTYgen will begin creating the key. The progress bar will reset to the start, and gradually move up again to track the progress of the key generation. It will not move evenly, and may occasionally slow down to a stop; this is unfortunately unavoidable, because key generation is a random process and it is impossible to reliably predict how long it will take.

When the key generation is complete, a new set of controls will appear in the window to indicate this.

The Key Fingerprint Box

The Key fingerprint box shows you a fingerprint value for the generated key. This is derived cryptographically from the public key value, so it doesn’t need to be kept secret; it is supposed to be more manageable for human beings than the public key itself.

The fingerprint value is intended to be cryptographically secure, in the sense that it is computationally infeasible for someone to invent a second key with the same fingerprint, or to find a key with a particular fingerprint.

Puttygen Generate Ssh Key Windows

Setting a Passphrase for Your Key

The Key passphrase and Confirm passphrase boxes allow you to choose a passphrase for your key. The passphrase will be used to encrypt the key on disk, so you will not be able to use the key without first entering the passphrase.

When you save the key, PuTTYgen will check that the Key passphrase and Confirm passphrase boxes both contain exactly the same passphrase, and will refuse to save the key otherwise.

If you leave the passphrase fields blank, the key will be saved unencrypted. You should not do this without good reason; if you do, your private key file on disk will be all an attacker needs to gain access to any machine configured to accept that key. If you want to be able to passwordless log in without having to type a passphrase every time, you should consider using Pageant so that your decrypted key is only held in memory rather than on disk.

Under special circumstances you may genuinely need to use a key with no passphrase; for example, if you need to run an automated batch script that needs to make an SSH connection, you can’t be there to type the passphrase. In this case we recommend you generate a special key for each specific batch script (or whatever) that needs one, and on the server side you should arrange that each key is restricted so that it can only be used for that specific purpose. The documentation for your SSH server should explain how to do this (it will probably vary between servers).

Choosing a good passphrase is difficult. Just as you shouldn’t use a dictionary word as a password because it’s easy for an attacker to run through a whole dictionary, you should not use a song lyric, quotation or other well-known sentence as a passphrase. If you want your passphrase to make grammatical sense, this cuts down the possibilities a lot and you should use a longer one as a result.

Do not forget your passphrase. There is no way to recover it.

Saving Your Private Key to a Disk File

Once you have generated a key, set a comment field and set a passphrase, you are ready to save your private key to disk.

Press the Save private key button. PuTTYgen will put up a dialog box asking you where to save the file. Select a directory, type in a file name, and press Save.

Saving Your Public Key to a Disk File

RFC 4716 specifies a standard format for storing SSH-2 public keys on disk. Some SSH servers (such as ssh.com’s) require a public key in this format in order to accept authentication with the corresponding private key. (Others, such as OpenSSH, use a different format)

To save your public key in the SSH-2 standard format, press the Save public key button in PuTTYgen. PuTTYgen will put up a dialog box asking you where to save the file. Select a directory, type in a file name, and press Save.

You will then probably want to copy the public key file to your SSH server machine.

If you use this option with an SSH-1 key, the file PuTTYgen saves will contain exactly the same text that appears in the Public key for pasting box. This is the only existing standard for SSH-1 public keys.

The text is copy of PuTTY User Manual or was inspired by it.

PuTTYgen is a key generator tool for creating pairs of public and private SSH keys. It is one of the components of the open-source networking client PuTTY. Although originally written for Microsoft Windows operating system, it is now officially available for multiple operating systems including macOS, Linux. PuTTYgen.exe is the graphical tool on Windows OS. While on the other side, Linux OS has the only command-line version could be accessible using SSH commands.

  • 1 Download PuTTYgen
    • 1.1 Download PuTTYgen on Windows
    • 1.2 Download PuTTYgen for Mac
    • 1.3 Download PuTTYgen for Ubuntu/Linux
      • 1.3.3 Types of Keys Supported on PuTTYgen

Puttygen aka Putty Key Generator

The key generation utility – PuTTYgen can create various public-key cryptosystems including Rivest–Shamir–Adleman (RSA), Digital Signature Algorithm (DSA), Elliptic Curve Digital Signature Algorithm (ECDSA), and Edwards-curve Digital Signature Algorithm (EdDSA) keys.

The aforementioned public-key cryptosystems principally focus on secure data transmission and digital signatures.

Although PuTTYgen collects keys in its native file format i.e. .ppk files, the keys can easily be converted to any file format. For Windows, the software interface is PuTTYgen.exe, whereas, for Linux OS the command-line adaptation is available using SSH commands.

How to use PuTTYgen?

PuTTYgen is used to generate public or private key pair for creating SSH keys. Below is the complete guidance about how to generate RSA key in the Windows operating system:

  1. Once you install the PuTTY on your machine, you can easily run PuTTYgen. For the same, go to Windows -> Start Menu -> All Programs -> PuTTY -> PuTTYgen.
  2. You will see the PuTTY key generator dialog box on your screen
  3. You will find a “Generate” button in that dialog. Clicking on it will lead to generating the keys for you.
  4. Now you will need to add a unique key passphrase in the Key passphrase and Confirm passphrase field.
  5. Click on the “Save Public Key” and “Save Private Key” buttons to save your public and private keys.
  6. You will see the text starting with ssh-RSA in the Public key for pasting into OpenSSH authorized_keys file field which is located at the top of the window. Copy that entire text to your clipboard by pressing ctrl+c as you will require the key to paste on your clipboard in the public key tool of control panel or directly on the cloud server.

Various Ways to Use RSA Key Pair

RSA key pair generated through PuTTYgen is used in two various ways defined as below:

  1. To assign while creating a new cloud server
    You can choose the public key from the given list of keys at the time of creating a cloud server. If you don’t find your key in that list, then first add and then assign it.
  2. Assign to an existing cloud server
    At the time of connecting to the cloud server, first of all, you need to tell PuTTY to use it for utilizing your newly created RSA key pair.

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PuTTYgen being a component of the terminal emulator PuTTY does not have to be downloaded separately, hence, comes with the PuTTY .msi installation package. You can follow the simple steps to download PuTTYgen software for your system. That is the reason why you don’t need to download PuTTYgen separately. Once you download PuTTY software, you will be able to install and run PuTTYgen easily in no time. Below is the complete instruction about how to download and install PuTTY on Windows.

Apart from that, it is also integrated into third-party programs such as WinSCP installation package. Below you can find a complete PuTTYgen download and installation guide for all operating systems.

Download PuTTYgen on Windows

To download PuTTYgen the primary requisite is to acquire the copy of PuTTY installation package. For the 64-bit operating system, one must install the 64-bit version of PuTTY, i.e. putty-64bit-<version>-installer.msi.Similarly, for the 32-bit operating system, the respective 32-bit version of PuTTY, i.e. putty-<version>-installer.msi needs to be installed.

To get PuTTY, go to PuTTY Installation Download page, whereby the complete installation package will be available with setup instructions, installation guide, and download links to all other components of PuTTY such as putty.exe, pscp.exe, psftp.exe, puttytel.exe, plink.exe, pageant.exe and putty.zip.


Following the successful download of the PuTTY installation package. It is time to install the program. Go to How to install PuTTY on Windows, whereby you will find the step by step guidance for PuTTY installation for Windows operating system.

After successfully downloading and installing PuTTY on your Windows machine, you are just 2-3 clicks away to run PuTTYgen. Follow the below-given step by step guidance to run PuTTYgen:

Run PuTTYgen on Windows

To run PuTTYgen, Go to Windows -> Start Menu -> All Programs -> PuTTY -> PuTTYgen. You will see a window for the PuTTY Key Generator on your screen.

Voila! Now you can generate public or private key pair using PuTTYgen.

Download PuTTYgen for Mac


Below is the detailed guide to download PuTTYgen on Mac operating system. Mac OS has a built-in command-line SSH client known as Terminal. To utilize it, go to Finder and then opt for Go -> utilities from the top menu. After that find the terminal which supports SSH connections to remote servers.

However, to run PuTTYgen for mac, the first one must have to install PuTTY. There are multiple ways to install PuTTY, which are Homebrew or MacPorts. Both alternatives will also install the command-line of adaptations of PuTTYgen.

Ported PuTTY for Mac

Mac has the port of PuTTY which can be installed in various ways described as below:

  1. Installation using Homebrew:
    First, install the ‘brew command line’ Once installed use the below-given command to install PuTTY:-
    sudo brew install putty
  2. Installation using MacPorts:
    First of all, one must install MacPorts and then use the command-line to install PuTTY. Here is the command to install PuTTY via MacPorts
    sudo port install putty
    Additionally, a user can also add a shortcut to the desktop by writing the following command line
    –cp /opt/local/bin/putty ~/Desktop/PuTTY

However, there is an alternative way to install PuTTY on Mac OS. Cyberduck is a widely used Mac OS SSH Client. Once PuTTY installed on the Mac OS, a user can convert PuTTY derived private key format to OpenSSH.

To convert the private key to standard PEM format, type the following command –

puttygen privatekey.ppk -O private-openssh -o privatekey.pem

You can also read the guide to convert .pem file to .ppk using puttygen.

Download PuTTYgen for Ubuntu/Linux

To download PuTTYgen for Ubuntu (Linux) operating system, a user to first install PuTTY. However, in some Linux distributions, the SSH key generation tool – PuTTYgen needs to be installed independently from the PuTTY client.

Putty Generate Ssh Key Windows

For example, Debian Linux requires the below-given code to install PuTTYgen:

sudo apt install putty-tools

Generate Key Pair for Authentication in Linux

To create the key pair for authentication in Linux use the below command:-

puttygen -t rsa -b 2048 -C '[email protected]' -o keyfile.ppk

Various Command Line Options of PuTTY in Linux

Below are few important command line options in the Linux operating system for PuTTY:

PuTTYgen [-t keytype [-b bits] [-q] keyfile]
[-C new-comment] [-P]
[-O output-type -p -l -L]
[-o output-file]

Options:

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  1. Keyfile – It is the name of the existing key file to read at the time of changing the current key.
  2. t keytype – The command specifies the type of key to creating. Its acceptable values are RSA and dsa.rsa1.
  3. -b bits – This command specifies a total number of bit in a particular key. 1024 is the perfect size for DSA key, while 2048 or 4096 are the perfect size for RSA keys.
  4. q – The command suppresses the message about progress at the time of key generation.
  5. -C new-comment – The command will specify the comment to describe the key. It can be used for the new and/or existing key. Key operation is not affected by a comment. However, it is used to recognize the key owner, it’s not reliable completely as any value can be applied to it.
  6. –P – Using the command will update the passphrase of a key. Passphrase helps to encrypt the private key. As passphrase can’t add or update on a command line, it prompts a new passphrase tool to alter it.
  7. –old-passphrase-file – The old password of the key remains in this file. The command is used when the key is protected by a passphrase.
  8. –new-passphrase file – This command prompts the new passphrase of the key. It comes in the action either at the time of generating a new key or while applying –P command to change the passphrase.
  9. -O output-type – This command defines what to give in output. By default, the private key is the output.

Thus, above are the prominent commands of PuTTYgen in Linux operating system. Besides that, there are many other commands available to perform various tasks from the command prompt in Linux at flank speed.

Types of Keys Supported on PuTTYgen

It is important to know the types of key PuTTYgen supports prior to using it. Below are the key types that it currently supports for SSH-2 and SSH-1 protocol:-

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  • SSH-1 protocol:- For SSH-1 only supports one key i.e. Rivest–Shamir–Adleman (RSA)
  • SSH-2 protocol: – SSH-2 supports multiple key types that include – Digital Signature Algorithm (DSA), Elliptic Curve Digital Signature Algorithm (ECDSA) and Ed25519.

The above description is a detailed brief on downloading and running PuTTYgen on all major operating systems. For further details please check the Download PuTTY page.