How to generate an SSH key in a browser and register the public key

When this guide is useful

This is for users who are looking for SSH key generation, Ed25519 key generation, RSA SSH key generation, OpenSSH public keys, and how to check SHA-256 fingerprints.

• Connect to the SSH server using public key authentication
• Register the SSH public key to Git hosting such as GitHub
• Additional information: SSH

How to choose Ed25519 and RSA

• Make Ed25519 your first choice in a new OpenSSH environment
• If compatibility with older connections is required, consider RSA 3072 bit or higher.
• Verify the public key to be registered using the SHA-256 fingerprint
• Add public key comments to the extent that users and devices can be identified.

Steps to generate and register an SSH key

1. Select Ed25519 or RSA and key length, and set a comment and save name.
2. Generate an SSH key and confirm successful signing/verification and SHA-256 fingerprint.
3. Save the public key and private key separately.
4. Register only the public key to the authorized_keys or Git service of the connection destination, and check the displayed fingerprint.
5. Settings

Additional information for this feature.

The private key you save from your browser is not encrypted with your passphrase. Do not leave it on a shared terminal, and on Unix-based OSes, restrict read permissions using chmod 600, etc.

Additional information for this feature.

Specific example: Creating an Ed25519 key for a new development device

For new development terminals, choose Ed25519 and add the user name or device name to the comment to make it easier to identify after registration.

After generating, check that the public key starts with ssh-ed25519, and check the SHA-256 fingerprint before and after registering it to the connection destination.

1. Select Ed25519 and enter the public key comment and a save name such as id_ed25519.
2. Check self-verification success and fingerprint after generation.
3. Save id_ed25519.pub and id_ed25519.
4. Register only the public key to the connection destination, and set permissions for the private key that are limited to the owner.

In critical production environments, prioritize your organization's key management rules and rotation procedures, and use ssh-keygen on management terminals when necessary.

Frequently asked questions

Should I register the public key or the private key on the server?

Register the public key with .pub. Please keep the private key safe and do not leave it outside the connection source terminal.

Will the generated SSH key be sent to the server?

Key generation, OpenSSH formalization, fingerprint calculation, and self-verification occur within the browser. The SSH key page also does not load advertisements or external APIs.