Key Management with ssh

ssh-copy-id

ssh-copy-id installs an ssh key on a server as an authorized key. It’s purpose is to provide access without requiring a password for each login.

This facilitates automated, passwordless logins and single sign-on using the ssh protocol. The ssh-copy-id tool is part of openssh.

Setting up public key authentication

Key based authentication in ssh is called public key authentication. The purpose of ssh-copy-id is to make setting up public key authentication easier. The process is as follows:

Generate an ssh key with the ssh-keygen command line util that comes with openssh.

With OpenSSH, an SSH key is created using ssh-keygen. In the simplest form, just run ssh-keygen and answer the questions. The following example illustates this.

# ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/home/ylo/.ssh/id_rsa): mykey Enter passphrase (empty for no passphrase):  Enter same passphrase again:  Your identification has been saved in mykey. Your public key has been saved in mykey.pub. The key fingerprint is: SHA256:GKW7yzA1J1qkr1Cr9MhUwAbHbF2NrIPEgZXeOUOz3Us ylo@klar The key's randomart image is: +---[RSA 2048]----+ |.*++ o.o.        | |.+B + oo.        | | +++ *+.         | | .o.Oo.+E        | |    ++B.S.       | |   o * =.        | |  + = o          | | + = = .         | |  + o o          | +----[SHA256]-----+ #