SSH Key Generator

What it's for

Make a new SSH key pair, the files ssh-keygen makes, for signing in to servers or to services such as GitHub and GitLab without a password. The key is made by your browser’s own cryptography and never leaves the page.

For example, when you’re on a computer without a terminal handy and need a key to give a hosting company, make it here and save both files.

How to use it

Choose a key type (Ed25519 suits almost everything; RSA is for older servers), type a comment (usually you@computer, to tell keys apart), and press Make a key pair. You get:

• The public key, one line to paste into a server’s authorized_keys or a website’s SSH settings.
• The private key, in OpenSSH’s own format, to keep in ~/.ssh/.
• Its fingerprints, to check against what a server shows.

Save downloads each file with its usual name (id_ed25519 and id_ed25519.pub, for example). The commands below set the private key’s permissions, add a passphrase and copy the public key to a server.

Example

Choose Ed25519, type the comment alice@laptop and press Make a key pair.

The public key starts ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAI and ends with alice@laptop. The table shows the type ssh-ed25519, size 256-bit, the comment, and a SHA-256 fingerprint starting SHA256:, different every time.

Good to know

The private key is saved without a passphrase; add one with ssh-keygen -p -f and the file’s name, as the commands show. The private key is shown only until you leave the page and is never stored. Ed25519 needs a recent browser. Treat the private key like a password: anyone with it can sign in as you.