FTP 101 – Part 14: Keys vs. Passwords – Which to use?
Published {$created} by Carsten Blum
When using SFTP for secure file transfers, you have two main authentication options:
Passwords
SSH keys
Both methods have their place, but the security differences are significant.
How Password Authentication Works
With password authentication, you:
Enter your username and password into your SFTP client.
The server checks if the credentials match.
If correct, access is granted.
Pros:
Simple to set up — just create a user and set a password.
No extra files or configuration on the client.
Cons:
Passwords can be guessed, stolen, or reused across sites.
Weak passwords are easily brute-forced.
Password databases can be compromised.
How SSH Key Authentication Works
With SSH key authentication:
You generate a key pair: public key and private key.
The public key is stored on the SFTP server.
The private key stays on your device and is never sent to the server.
Authentication happens by proving you own the matching private key.
Pros:
Extremely resistant to brute-force attacks.
Private key never leaves your device.
Can be protected with a passphrase for extra security.
Cons:
Slightly more complex to set up.
Requires secure handling of the private key file.
Which Is More Secure?
In almost all cases, SSH keys are more secure than passwords.They provide:
Stronger encryption
Protection against credential reuse
Reduced risk from phishing attacks
Many managed SFTP hosting providers (including ftpgrid) recommend or enforce key-based authentication for high-security use cases.
Best Practices for SSH Keys
Use ed25519 keys for strong security and fast performance, learn how to create ed25519 keys here.
Protect your private key with a strong passphrase.
Store your private key securely and back it up.
Rotate keys periodically.
Remove unused keys from the server.
Using Both Methods
Some organizations use both:
Keys for automated scripts and trusted users.
Passwords for occasional or temporary access.
This can be a good compromise if you need flexibility, but make sure password users still follow strong password policies.
Conclusion
For the best SFTP security, choose SSH keys over passwords.They are harder to steal, impossible to guess, and easy to revoke if needed.If you’re running your own SFTP server, make key-based authentication the default — and if you use ftpgrid, you can set it up in minutes.