How to create an SSH key pair — ssh-keygen with Ed25519

You are setting up key-based login from scratch.

Every flag and config keyword was checked against the OpenSSH 9.6 man pages, and the config examples were parsed for real with ssh -G.

ssh-keygen -t ed25519 -C "you@example.com"
# private key: ~/.ssh/id_ed25519      → never share it, never commit it
# public key:  ~/.ssh/id_ed25519.pub  → this is the one you upload
# set a passphrase: it's the second factor protecting the file

Good to know

The private key never leaves your machine — never share it, never commit it. The .pub file is the one you upload. A passphrase is the second factor protecting the file.

SSH Cheatsheet one-page card — commands that actually work — The full one-page card — SSH Cheatsheet. Get the complete cheatsheet on GitHub