KeyGenerator.java

public static void generateKey(String username)
{
    try
    {
        KeyPairGenerator pair = KeyPairGenerator.getInstance("RSA");
        pair.initialize(2048);
        KeyPair keyPair = pair.generateKeyPair();

        PublicKey pub = keyPair.getPublic();
        PrivateKey pri = keyPair.getPrivate();
        byte[] publicData = pub.getEncoded();
        byte[] privateData = pri.getEncoded();

        Path publicKey = Paths.get(BukkitSSH.instance.keys.getAbsolutePath() + File.separator + username);
        Path privateKey = Paths.get(BukkitSSH.instance.keys.getAbsolutePath() + File.separator + "private"
                + File.separator + username);
        Files.write(publicKey, Base64.encodeBase64(publicData));
        Files.write(privateKey, Base64.encodeBase64(privateData));
    }
    catch (NoSuchAlgorithmException | IOException e)
    {
        e.printStackTrace();
    }
}