How Do You Generate A Key Pair

Create and add your SSH key pair. It is best practice to use Git over SSH instead of Git over HTTP. In order to use SSH, you will need to: Create an SSH key pair; Add your SSH public key to GitLab. Creating your SSH key pair. Go to your command line. Follow the instructions to generate your SSH key pair. If you see an existing public and private key pair listed (for example idrsa.pub and idrsa) that you’d like to use, you can skip Step 2 and go straight to Step 3. Step 2: Generate a new SSH key With your command line tool still open, enter the text shown below.

• How To Generate A Key Pair In Linux
• How To Generate A Key Pair
• How Do You Generate A Key Pair App

This guide contains description of setting up public key authentication for use with WinSCP. You may want to learn more about public key authentication or SSH keys instead.

• Configure Server to Accept Public Key

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Before starting you should:

• Have WinSCP installed;
• Know how to connect to the server without public key authentication.

If you do not have a key pair yet, start with generating new key pair.

Connect to your SSH server using WinSCP with the SSH protocol, using other means of authentication than public key, e.g. typically using password authentication.

Once logged in, configure your server to accept your public key. That varies with SSH server software being used. The most common SSH server is OpenSSH.

You can use Session > Install Public Key into Server command on the main window, or Tools > Install Public Key into Server command on SSH > Authentication page page on Advanced Site Settings dialog. The functionality of the command is similar to that of OpenSSH ssh-copy-id command.

Or you can configure the key manually:

• Navigate into a .ssh subdirectory of your account home directory. You may need to enable showing hidden files to see the directory. If the directory does not exists, you need to create it first.
• Once there, open a file authorized_keys for editing. Again you may have to create this file, if this is your first key.
• Switch to the PuTTYgen window, select all of the text in the Public key for pasting into OpenSSH authorized_keys file box, and copy it to the clipboard (Ctrl+C). Then, switch back to the editor and insert the data into the open file, making sure it ends up all on one line. Save the file. WinSCP can show you the public key too.
• Ensure that your account home directory, your .ssh directory and file authorized_keys are not group-writable or world-writable. Recommended permissions for .ssh directory are 700. Recommended permissions for authorized_keys files are 600. Read more about changing permissions.

• Save a public key file from PuTTYgen, and copy that into the .ssh2 subdirectory of your account home directory.
• In the same subdirectory, edit (or create) a file called authorization. In this file you should put a line like Key mykey.pub, with mykey.pub replaced by the name of your key file.

For other SSH server software, you should refer to the manual for that server.

When configuring session, specify path to your private key on SSH > Authentication page of Advanced Site Settings dialog.

Alternatively, load the private key into Pageant.

Cloud providers have typically their own mechanism to setup a public key authentication to virtual servers running in the cloud.

For details see guides for connecting to:

• Amazon EC2;
• Google Compute Engine;
• Microsoft Azure.

• Using Public Keys for Authentication;
• Using PuTTYgen;
• Understanding SSH Key Pairs.

While Encrypting a File with a Password from the Command Line using OpenSSLis very useful in its own right, the real power of the OpenSSL library is itsability to support the use of public key cryptograph for encrypting orvalidating data in an unattended manner (where the password is not required toencrypt) is done with public keys.

The Commands to Run

Generate a 2048 bit RSA Key

You can generate a public and private RSA key pair like this:

openssl genrsa -des3 -out private.pem 2048

That generates a 2048-bit RSA key pair, encrypts them with a password you provideand writes them to a file. You need to next extract the public key file. You willuse this, for instance, on your web server to encrypt content so that it canonly be read with the private key.

Export the RSA Public Key to a File

How To Generate A Key Pair In Linux

This is a command that is

openssl rsa -in private.pem -outform PEM -pubout -out public.pem

The -pubout flag is really important. Be sure to include it.

Next open the public.pem and ensure that it starts with-----BEGIN PUBLIC KEY-----. This is how you know that this file is thepublic key of the pair and not a private key.

To check the file from the command line you can use the less command, like this:

less public.pem

Do Not Run This, it Exports the Private Key

A previous version of the post gave this example in error.

openssl rsa -in private.pem -out private_unencrypted.pem -outform PEM

The error is that the -pubout was dropped from the end of the command.That changes the meaning of the command from that of exporting the public keyto exporting the private key outside of its encrypted wrapper. Inspecting theoutput file, in this case private_unencrypted.pem clearly shows that the keyis a RSA private key as it starts with -----BEGIN RSA PRIVATE KEY-----.

Visually Inspect Your Key Files

It is important to visually inspect you private and public key files to makesure that they are what you expect. OpenSSL will clearly explain the nature ofthe key block with a -----BEGIN RSA PRIVATE KEY----- or -----BEGIN PUBLIC KEY-----.

You can use less to inspect each of your two files in turn:

• less private.pem to verify that it starts with a -----BEGIN RSA PRIVATE KEY-----
• less public.pem to verify that it starts with a -----BEGIN PUBLIC KEY-----

How To Generate A Key Pair

The next section shows a full example of what each key file should look like.

The Generated Key Files

The generated files are base64-encoded encryption keys in plain text format.If you select a password for your private key, its file will be encrypted withyour password. Be sure to remember this password or the key pair becomes useless.

The private.pem file looks something like this:

How Do You Generate A Key Pair App

The public key, public.pem, file looks like:

Protecting Your Keys

Depending on the nature of the information you will protect, it’s important tokeep the private key backed up and secret. The public key can be distributedanywhere or embedded in your web application scripts, such as in your PHP,Ruby, or other scripts. Again, backup your keys!

Remember, if the key goes away the data encrypted to it is gone. Keeping aprinted copy of the key material in a sealed envelope in a bank safety depositbox is a good way to protect important keys against loss due to fire or harddrive failure.

Oh, and one last thing.

If you, dear reader, were planning any funny business with the private key that I have just published here. Know that they were made especially for this series of blog posts. I do not use them for anything else.

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