PuTTYgen is a key generator. It generates pairs of public and private keys to be used with PuTTY, PSCP, and Plink, as well as the PuTTY authentication agent, Pageant. PuTTYgen generates RSA, DSA, ECDSA, and Ed25519 keys. When you run PuTTYgen you will see a window where you have two choices: ‘Generate’, to generate a new public/private key pair, or ‘Load’ to load in an existing private key.
First, you need to select which type of key you want to generate, and also select the strength of the key.
Then press the ‘Generate’ button, to actually generate the key.
Once you have generated the key, select a comment field and a passphrase.
Now you’re ready to save the private key to disk; press the ‘Save private key’ button.
Before generating a key pair using PuTTYgen, you need to select which type of key you need. PuTTYgen currently supports these types of key:
An RSA key for use with the SSH-1 protocol.
An RSA key for use with the SSH-2 protocol.
A DSA key for use with the SSH-2 protocol.
An ECDSA (elliptic curve DSA) key for use with the SSH-2 protocol.
An Ed25519 key (another elliptic curve algorithm) for use with the SSH-2 protocol.
Connect to your SSH server using PuTTY with the SSH protocol. When the connection succeeds you will be prompted for your user name and password to login. Once logged in, you must configure the server to accept your public key for authentication: