SSH

Abstract

---

• Secure SHell
• A Network Protocol used to enable developers to manage servers and network devices remotely

Public-key Cryptography Authentication

---

• We can use username and password, but SSH supports Asymmetric Cryptography which is more secure

Setup Public-key Cryptography Authentication

1. Generate Public Key and Private Key that are 4096 Bit using RSA (A good balance of security & performance)

ssh-keygen -t rsa -b 4096

2. Copy the public key(the key ends with .pub) to the remote Host (Should be stored inside ~/.ssh/authorized_keys by default)

ssh-copy-id -i /path/to/your/public_key username@remote_hostname

3. Disable password authentication & enable public key authentication. Modify /etc/ssh/sshd_config, uncomment and set the following attributes

PasswordAuthentication no
PubkeyAuthentication yes

4. Restart the SSH server on the remote host

# Linux
sudo systemctl restart sshd
 
# MacOS
sudo launchctl stop com.openssh.sshd
sudo launchctl start com.openssh.sshd

5. SSH into remote host with private key!

ssh -i /path/to/your/private_key username@remote_hostname