How do I make a RSA key pair for a SSH connection?

Note:  These instructions are for Linux or Mac OS users only. Those connecting from a Windows host should skip to the Instructions (Windows) section.

1. Issue the following command at a shell prompt (by default, Mac OS Terminal uses a bash shell):

ssh-keygen -t rsa -b 2048

This will create a RSA public/private key pair in the .ssh directory below your account’s home directory. For example:

• Location:  ~/.ssh (where ~ is the home directory)
• Private key file name:  id_rsa
• Public key file name: id_rsa.pub

1. cd ~/.ssh                   # Change directories to the keys location
2. ls -l                           # Verify the keys are available
3. chmod 400 id_rsa*     # Restrict read/write privileges to both keys

Instructions (Windows)

Windows does not ship with software for generating SSH keys. Although many third-party software packages can be used, this Lab Step uses PuTTYgen to generate SSH keys.

1. Invoke PuTTYgen on your local Windows host
2. Leave the Parameters at their default values. (RSA keys, 2048 bits.)
3. Click Generate. Move your mouse to the appropriate area of the window as directed
4. Click Save public key. Save the public key in a safe place with a recognizable name. (PublicWin)
5. Click Save private key
6. Click Yes when presented with the PuTTYgen warning about a blank passphrase

A passphrase can be used for an additional level of security. Leave it blank for this lab.

1. Save the private key in a safe place with a recognizable name. Note that .ppk will automatically be appended to the name you provide (PrivateWin.ppk)  Reminder: It is a security risk to share your keys with others!

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