非對稱加密

package net.foreworld.util;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

/**
 *
 * @author huangxin <3203317@qq.com>
 *
 */
public class RSACoder {

	public static final String RSA = "RSA";

	/**
	 * Client Mode
	 *
	 * @throws Exception
	 */
	private static void mode_cli() throws Exception {
		String message = "123456 hello 世界！";

		String[] keys = genKey();
		System.err.println("pubkey: " + keys[0]);
		System.err.println("prikey: " + keys[1]);

		// 私鑰加密
		String edata = encrypt(Mode.CLIENT, keys[1], message);
		System.out.println("prikey encrypt: " + edata);

		// 公鑰解密
		String ddata = decrypt(Mode.CLIENT, keys[0], edata);
		System.err.println("pubkey decrypt: " + ddata);
	}

	/**
	 * Server Mode
	 *
	 * @throws Exception
	 */
	private static void mode_serv() throws Exception {
		String message = "654321 hello world!";

		String[] keys = genKey();
		System.err.println("pubkey: " + keys[0]);
		System.err.println("prikey: " + keys[1]);

		// 公鑰加密
		String edata = encrypt(Mode.SERVER, keys[0], message);
		System.out.println("pubkey encrypt: " + edata);

		// 私鑰解密
		String ddata = decrypt(Mode.SERVER, keys[1], edata);
		System.err.println("prikey decrypt: " + ddata);
	}

	public static void main(String[] args) throws Exception {
		mode_serv();
		mode_cli();
	}

	/**
	 *
	 * @return
	 * @throws NoSuchAlgorithmException
	 */
	public static String[] genKey() throws NoSuchAlgorithmException {
		KeyPairGenerator genor = KeyPairGenerator.getInstance(RSA);
		genor.initialize(512);

		KeyPair pair = genor.generateKeyPair();

		RSAPublicKey pubKey = (RSAPublicKey) pair.getPublic();
		RSAPrivateKey priKey = (RSAPrivateKey) pair.getPrivate();

		return new String[] { encodeBase64String(pubKey.getEncoded()),
				encodeBase64String(priKey.getEncoded()) };
	}

	/**
	 *
	 * @param b
	 * @return
	 */
	public static String encodeBase64String(byte[] b) {
		return Base64.encodeBase64String(b);
	}

	/**
	 *
	 * @param s
	 * @return
	 */
	public static byte[] decodeBase64(String s) {
		return Base64.decodeBase64(s);
	}

	/**
	 *
	 * @param mode
	 * @param key
	 * @param data
	 * @return
	 * @throws Exception
	 */
	public static String encrypt(Mode mode, String key, String data)
			throws Exception {

		KeyFactory factory = KeyFactory.getInstance(RSA);
		Cipher cipher = Cipher.getInstance(RSA);

		if (Mode.SERVER == mode) {
			X509EncodedKeySpec spec = new X509EncodedKeySpec(decodeBase64(key));
			PublicKey pubKey = factory.generatePublic(spec);
			cipher.init(Cipher.ENCRYPT_MODE, pubKey);
		} else {
			PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decodeBase64(key));
			PrivateKey priKey = factory.generatePrivate(spec);
			cipher.init(Cipher.ENCRYPT_MODE, priKey);
		}

		byte[] result = cipher.doFinal(data.getBytes());
		return encodeBase64String(result);
	}

	/**
	 *
	 * @param mode
	 * @param key
	 * @param data
	 * @return
	 * @throws Exception
	 */
	public static String decrypt(Mode mode, String key, String data)
			throws Exception {

		KeyFactory factory = KeyFactory.getInstance(RSA);
		Cipher cipher = Cipher.getInstance(RSA);

		if (Mode.SERVER == mode) {
			PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decodeBase64(key));
			PrivateKey priKey = factory.generatePrivate(spec);
			cipher.init(Cipher.DECRYPT_MODE, priKey);
		} else {
			X509EncodedKeySpec spec = new X509EncodedKeySpec(decodeBase64(key));
			PublicKey pubKey = factory.generatePublic(spec);
			cipher.init(Cipher.DECRYPT_MODE, pubKey);
		}

		byte[] result = cipher.doFinal(decodeBase64(data));
		return (new String(result));
	}

	public enum Mode {
		SERVER, CLIENT
	}

}

pubkey: MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBALm2mQ3xdwhWN5Q7ac7uFqky7zzpVWImZyfOAi0mUNgRcDciOhml3yJlVc82O8U9DnacWpi2sporixlzMNqqX88CAwEAAQ==
prikey: MIIBUwIBADANBgkqhkiG9w0BAQEFAASCAT0wggE5AgEAAkEAubaZDfF3CFY3lDtpzu4WqTLvPOlVYiZnJ84CLSZQ2BFwNyI6GaXfImVVzzY7xT0OdpxamLaymiuLGXMw2qpfzwIDAQABAkBOt8JKcbZVt03ZrBFeX/cFAwz7EaBaeRKygZTUlHAiFRFSXY7froTKcDtvHXlNVqFE7u3Z4V11wjsNytcFvdexAiEA3NqhTj1RJnxNqcJBpjQJpp/OSnICNo48Sk/1RLCXNJkCIQDXRF56/r0E3xKA2D444z90OpbtnOb5QfylIq5vY5mQpwIgN8PsnvjUmMciRQ8LzI+vMCeBy0JmVKgtiQYPhDyisWECIDG5/mVFIR7V9O1EhqMXg5nyytiazRQ5NQZki4z5ogizAiAoaxxvUvJ2S1yob3ZGEUqjq/W0FUC07bPRQJY6mCuCNQ==
pubkey encrypt: BbZoVTpRhkVGGtj7nXZg31Ir3/9oosSbWUhtScuaiPI1fB/vOGIlnPMYk7sXt3y3iA5GtPiV6JyaWw1+ugAk4w==
prikey decrypt: 654321 hello world!

pubkey: MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAIhtyBCryOFuEiO5x7LQXFPp0hmXv/xPatYTWo5+VZW+QuVcP+Brp52gQsgGDzgtTYHsUFy4ifX4C8HBLWS10IUCAwEAAQ==
prikey: MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAiG3IEKvI4W4SI7nHstBcU+nSGZe//E9q1hNajn5Vlb5C5Vw/4GunnaBCyAYPOC1NgexQXLiJ9fgLwcEtZLXQhQIDAQABAkAMC/2dkz2ywkBxzSbYIFP2yO/XeLHoOq8JZj4Z1QgDp99AAH6TVrMNkFOaKUwOdtAOuhcG4aYCaBOipPBFRGQFAiEAw8WjhwkLxCf77M0Hw3RlVwIYxop7kyCOVHh3/Tm74ysCIQCyZnfM+gACafJRiP+zsDCa0PNbEFyCk37yqi8XkB4DDwIhAKzUkU5INSQB7I0cYIsz+bc7eaXlYbz8k8qM49khG/crAiBPp6zqGt4SNdf6S99QDeVF2vItwNptewn9s7sfHDwqRQIgQikpSOWDe/Deabln/E1Iof23z2KnM2lSeJoltXgYiM4=
prikey encrypt: E0b3Ms3sjDcEmItK3aMiguu3h+rbkAwZdqIjpUZcyC8NMFcea9xbzHATqRdCrdhYJShusff547Of8FBhpUNpAw==
pubkey decrypt: 123456 hello 世界！