Generating an SSH keypair in Linux

In order to generate an SSH keypair in Linux, we recommend using the command ssh-keygen.

If system does not see this packet installed, install the latest updates:

Ubuntu and Debian family
sudo apt-get update && apt-get install openssh-client
CentOS and Red Hat
sudo yum install openssh-clients

After that, use the following command in terminal:

ssh-keygen

with additional flags:

-t

rsa authentication key type

-b

4096 bit length, 2048 if not specified. Available values: 1024, 2048, 4096. The greater the value, the more complicated the key will be.

-C

user@server name for identification at the end of the file

-f

~/.ssh/keys/keylocation location of folder with ssh keys

-N

passphrase, can be omitted if user prefers connecting without additional key security

../../../../_images/ssh1.png

Application will ask for the name of the key. Press Enter for defaults:

  • id_rsa for private and

  • id_rsa.pub for public key and passphrase (pressing Enter ignores it).

../../../../_images/ssh2.png

Next, ssh-keygen will show

  • location, where the keys are saved,

  • fingerprint of keypair and certain

  • semi-graphic image as expression of randomness in generating unique key.

../../../../_images/ssh3.png

To avoid problem with rejecting files due to too open permissions, navigate to the folder containing both keys and enter command:

chmod 600 id_rsa && chmod 600 id_rsa.pub