SSH key pair generator

SSH keys let you log in to servers and push to Git hosts without passwords. You keep the private key on your computer and copy the public key to the server or service. This tool generates an RSA SSH key pair in OpenSSH format locally in your browser.

How to use it

1. Choose the key size, 4096 bits recommended for RSA, and an optional comment such as your email.
2. Generate the key pair.
3. Save the private key as ~/.ssh/id_rsa and the public key as ~/.ssh/id_rsa.pub.
4. Set permissions: chmod 600 ~/.ssh/id_rsa.
5. Add the public key to the server's ~/.ssh/authorized_keys or to GitHub or GitLab under SSH keys.

Key formats

The public key is one line: ssh-rsa AAAAB3NzaC1yc2E... [email protected]. The private key begins with -----BEGIN OPENSSH PRIVATE KEY----- or, in older PEM format, -----BEGIN RSA PRIVATE KEY-----. Both work with OpenSSH.

The command-line way

• ssh-keygen -t ed25519 -C '[email protected]' creates a modern Ed25519 key, recommended for new keys.
• ssh-keygen -t rsa -b 4096 creates an RSA key for older systems.
• ssh-copy-id user@server installs the public key on a server.

Security best practices

• Protect the private key with a passphrase and use ssh-agent so you only type it once per session.
• Never share or upload the private key. Only the .pub file is shared.
• Use a separate key per device so one lost laptop can be revoked without affecting others.
• For long-term or high-value keys, generating them with ssh-keygen on your own machine is the safest option.