SshKeyPairGenerator.java

/**
 * Copyright 2003-2016 SSHTOOLS Limited. All Rights Reserved.
 *
 * For product documentation visit https://www.sshtools.com/
 *
 * This file is part of J2SSH Maverick.
 *
 * J2SSH Maverick is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * J2SSH Maverick is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with J2SSH Maverick.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.sshtools.publickey;

import java.io.IOException;

import com.sshtools.ssh.SshException;
import com.sshtools.ssh.components.ComponentManager;
import com.sshtools.ssh.components.SshKeyPair;

/**
 * <p>
 * Generate public/private key pairs.
 * </p>
 * <p>
 * To generate a new pair use the following code <blockquote>
 * 
 * <pre>
 * SshKeyPair pair = SshKeyPairGenerator.generateKeyPair(
 * 		SshKeyPairGenerator.SSH2_RSA, 1024);
 * </pre>
 * 
 * </blockquote> To create formatted key file for the public key use:
 * <blockquote>
 * 
 * <pre>
 * SshPublicKeyFile pubfile = SshPublicKeyFileFactory.create(pair.getPublicKey(),
 * 		"Some comment", SshPublicKeyFileFactory.OPENSSH_FORMAT);
 * FileOutputStream fout = new FileOutputStream("mykey.pub");
 * fout.write(pubfile.getFormattedKey());
 * fout.close();
 * </pre>
 * 
 * <blockquote> To create a formatted, encrypted private key file use:
 * <blockquote>
 * 
 * <pre>
 * SshPrivateKeyFile prvfile = SshPrivateKeyFileFactory.create(pair,
 * 		"my passphrase", "Some comment",
 * 		SshPrivateKeyFileFactory.OPENSSH_FORMAT);
 * FileOutputStream fout = new FileOutputStream("mykey");
 * fout.write(prvfile.getFormattedKey());
 * fout.close();
 * </pre>
 * 
 * <blockquote>
 * </p>
 * 
 * @author Lee David Painter
 */
public class SshKeyPairGenerator {

	public static final String SSH1_RSA = "rsa1";
	public static final String SSH2_RSA = "ssh-rsa";
	public static final String SSH2_DSA = "ssh-dss";

	/**
	 * Generates a new key pair.
	 * 
	 * @param algorithm
	 * @param bits
	 * @return SshKeyPair
	 * @throws IOException
	 */
	public static SshKeyPair generateKeyPair(String algorithm, int bits)
			throws IOException, SshException {

		if (!SSH2_RSA.equalsIgnoreCase(algorithm)
				&& !SSH2_DSA.equalsIgnoreCase(algorithm)) {
			throw new IOException(algorithm
					+ " is not a supported key algorithm!");
		}

		SshKeyPair pair = new SshKeyPair();

		if (SSH2_RSA.equalsIgnoreCase(algorithm)) {
			pair = ComponentManager.getInstance().generateRsaKeyPair(bits);
		} else {
			pair = ComponentManager.getInstance().generateDsaKeyPair(bits);
		}

		return pair;
	}

}