SSH Key Generator: Create Ed25519, ECDSA & RSA Keys

Understanding SSH Keys

SSH keys provide a more secure and convenient alternative to password-based authentication. Instead of typing a password every time you connect to a server or push code to a Git repository, SSH uses a pair of cryptographic keys -- a private key that stays on your machine and a public key that you share with servers. The server verifies your identity mathematically without your secret ever crossing the network.

Modern SSH supports several key types. Ed25519 is the recommended choice for most users -- it offers strong security with compact key sizes and fast operations. ECDSA provides similar elliptic curve security with broader compatibility on older systems. RSA remains widely supported and is the only option for some legacy systems, though it requires longer key lengths (at least 3072 bits, preferably 4096) to match the security of newer algorithms.

How to Use the SSH Key Generator

CheckTown's SSH Key Generator creates key pairs directly in your browser without sending any data to a server.

• Select your key algorithm -- Ed25519 (recommended), ECDSA (P-256, P-384, P-521), or RSA (2048, 3072, 4096 bits)
• Optionally add a comment to identify the key (typically your email address) and a passphrase for additional protection
• Click Generate to create your key pair -- the private key and public key appear in separate fields ready to copy
• Save the private key to your local machine (typically at ~/.ssh/id_ed25519) and add the public key to your server or Git hosting provider

SSH Key Security Tips

SSH keys are powerful credentials. Protecting them properly is essential to maintaining the security of your servers and accounts.

• Always add a passphrase to your private key -- if the key file is stolen, the passphrase prevents immediate use by an attacker
• Set strict file permissions on your private key file -- use chmod 600 so only your user account can read it, and chmod 700 on your .ssh directory
• Use separate key pairs for different purposes -- one for work servers, another for personal projects, and another for Git hosting. This limits exposure if one key is compromised

Frequently Asked Questions

Which SSH key type should I use?

Use Ed25519 unless you have a specific reason not to. It provides strong security with the smallest key size (256 bits), fast signature generation, and resistance to certain side-channel attacks. If you need compatibility with older systems that do not support Ed25519, use ECDSA with the P-256 curve. Only use RSA if the remote system requires it, and always use at least 4096 bits.

Is it safe to generate SSH keys in a browser?

This tool generates keys entirely in your browser using the Web Crypto API. No private key data is ever sent to any server -- all cryptographic operations happen locally on your device. You can verify this by checking the network tab in your browser developer tools during key generation. For maximum security on high-value servers, you can also generate keys locally using ssh-keygen on your terminal.

How do I add my public key to a server?

Copy your public key and append it to the ~/.ssh/authorized_keys file on the remote server. You can do this with the ssh-copy-id command, or manually by pasting the public key on a new line in the authorized_keys file. Make sure the authorized_keys file has permissions set to 644 and the .ssh directory has permissions set to 700. On Git platforms like GitHub or GitLab, paste your public key in the SSH keys section of your account settings.