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What is Passwordless SSH?
With this cryptographic protocol, you can manage machines, copy, or move files on a remote server via encrypted channels. There are two ways to login onto a remote system over SSH – using password authentication or public key authentication (passwordless SSH login).
What does SSH-copy-ID do?
Ssh-copy-id for copying SSH keys to servers. ssh-copy-id installs an SSH key on a server as an authorized key. Its purpose is to provision access without requiring a password for each login. This facilitates automated, passwordless logins and single sign-on using the SSH protocol.
How to automate SSH authentication without passwords?
The openssh_keypair module uses ssh-keygen to generate keys and the authorized_key module adds and removes SSH authorized keys for particular user accounts. SSH key pairs are only one way to automate authentication without passwords.
Is there a way to do passwordless SSH with OpenSSH?
This setup does not feel like passwordless SSH. However, there are caching mechanisms that allow you to enter the key passphrase once and then use the key over and over without reentering that passphrase. OpenSSH comes with an ssh-agent daemon and an ssh-add utility to cache the unlocked private key.
Can a private key be used for passwordless SSH?
By itself, a passphrase-protected private key requires the passphrase to be entered each time the key is used. This setup does not feel like passwordless SSH. However, there are caching mechanisms that allow you to enter the key passphrase once and then use the key over and over without reentering that passphrase.
Is it safe to share a SSH key?
The private key should never be shared with anyone and should be kept safe. In order to use SSH keys to connect to a remote computer, one must first create an SSH key pair on one’s computer, then copy the public SSH key to the remote computer.