SSH: Generate OpenSSL RSA Key Pair from the Command Line

https://rietta.com/blog/openssl-generating-rsa-key-from-command/ https://en.wikibooks.org/wiki/Cryptography/Generate_a_keypair_using_OpenSSL

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

openssl genrsa -aes256 -out private.pem 2048

Public key:

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

Use key for ssh:

1. Copy private.pem to a text file: i.e. key.txt (note you don't HAVE to create a new file. You can do steps 2 and 3 with the private.pem).
2. Set permission to not be too open:
   • chmod 400 key.txt
3. Ssh with that key:
   • ssh -i key.txt [email protected]

Using ssh-keygen (github example)

$ ssh-keygen -t rsa -b 4096 -C "[email protected]"

From https://help.github.com/en/github/authenticating-to-github/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent

Then add the key to ssh: $ ssh-add ~/.ssh/id_rsa

$ ssh -i ssh_key.txt user@IP