When you connect to a Linux VPS using SSH, you need to prove you have permission to access the server. This process is called authentication. There are two common ways to do this: password authentication and SSH key authentication.
Both methods allow you to connect to your VPS securely, but they work differently. In this guide, we will explain how each method works, their main differences, and which one is better for your Linux VPS.
What is Password Authentication?
Password authentication is the simplest way to connect to a Linux VPS using SSH. You enter your username and password to access the server. For example, you can connect to your VPS using this command:
ssh root@server_ip_address
The server will ask for your password. If you enter the correct password, you can access your VPS. Password authentication is easy to use because you do not need to create or manage SSH keys. However, it can be less secure if you use a weak password. For example, attackers may try common passwords to gain access to your server.
Using a strong and unique password helps reduce this risk.
What is SSH Key Authentication?
SSH key authentication is another way to connect to a Linux VPS. Instead of using your account password, it uses two cryptographic keys:
Public key: Stored on your VPS to help verify your identity.
Private key: Stored on your computer and used to prove that you have the matching key.
These two keys work together to verify your identity when connecting to the server.
A guide to setting up an SSH key.
When you reach your server, you will not need to enter your VPS account password. However, you may need to enter your SSH key passphrase if you created one.
SSH Key vs Password Authentication: Key differences
Although both methods let you access your Linux VPS, they differ in several important ways.
Security: Password authentication depends on how strong your password is. SSH key authentication generally provides better security because it uses cryptographic keys.
Ease of setup: Password authentication is easier for beginners because you only need a username and password. SSH key authentication requires creating a key pair and adding the public key to your VPS.
Brute-force attacks: Attackers can try guessing passwords to access your VPS. SSH keys protect against traditional password-guessing attacks.
Ease of use: Password authentication usually requires you to enter your password each time you connect. SSH keys let you connect without entering your VPS account password.
Automation: SSH keys are more convenient for automated tasks, such as running scripts or transferring files between servers.
Credential management: With password authentication, you need to remember or securely store your password. With SSH keys, you need to keep your private key safe.
Which authentication method is better for a Linux VPS?
For most Linux VPS users, SSH key authentication is the better option because it provides stronger protection against password-guessing attacks. Password authentication can still be useful for beginners or during initial server setup. However, use a strong, unique password to protect your server.
If you use SSH keys, protect your private key with a passphrase.
For additional security, you can disable SSH password authentication after setting up and successfully testing SSH key access. Make sure you have a working way to access your server before making this change to avoid getting locked out.
Conclusion
SSH key and password authentication are two common ways to access a Linux VPS. Password authentication is simple and easy to set up, while SSH key authentication offers better protection against password-based attacks and makes regular server management more convenient.