What is SSH key auth?

Logging into SSH with an Ed25519 key pair instead of a password — the first move in hardening remote access.

How it works

Passwords are brute-forceable; a 256-bit key is not. You generate a keypair, put the public key on the server, and disable password auth. Always test key login BEFORE disabling passwords or you lock yourself out.

Example

In practiceGenerate an Ed25519 key, copy the public key to the server, confirm key login works, then set PasswordAuthentication no.

Why Ed25519 over RSA?

Smaller, faster, and no weak-key footguns. It's the modern default.

Go deeper: Build a Hardened Linux Workstation

The complete, step-by-step guide — every command, config, and the reasoning behind it.

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