关于RSA加密算法的工具类

关于RSA加密算法的工具类

最近在捣鼓SSO（单点登录），就是一个在应用（系统）登录之后，当切换其他应用（系统）的时候，可以省去登录，提高用户的使用的便捷。（具体有时间在写）

期间涉及的安全问题，发送数据涉及账户密码以及分布系统之间的信息安全问题。

package test.rsa;

import java.io.*;
import java.math.BigInteger;
import java.security.*;
import java.security.interfaces.*;
import java.security.spec.*;
import javax.crypto.*;
import org.bouncycastle.util.encoders.Hex;
import sun.misc.*;

public class TestRSA {
	/**
	 * * 生成密钥对 *
	 * 
	 * @return KeyPair *
	 * @throws EncryptException
	 */
	public static KeyPair generateKeyPair() throws Exception {
		try {
			KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",
					new org.bouncycastle.jce.provider.BouncyCastleProvider());
			final int KEY_SIZE = 1024;// 块加密的大小，是不要太大，否则效率会低
			keyPairGen.initialize(KEY_SIZE, new SecureRandom());
			KeyPair keyPair = keyPairGen.generateKeyPair();
			saveKeyPair(keyPair);
			return keyPair;
		} catch (Exception e) {
			throw new Exception(e.getMessage());
		}
	}

	public static KeyPair getKeyPair() throws Exception {
		FileInputStream fis = new FileInputStream(
				"D:/javasoft/TempTest/RSAKey.txt");
		ObjectInputStream oos = new ObjectInputStream(fis);
		KeyPair kp = (KeyPair) oos.readObject();
		oos.close();
		fis.close();
		return kp;
	}

	public static void saveKeyPair(KeyPair kp) throws Exception {

		FileOutputStream fos = new FileOutputStream(
				"D:/javasoft/TempTest/RSAKey.txt");
		ObjectOutputStream oos = new ObjectOutputStream(fos);
		// 生成密钥
		oos.writeObject(kp);
		oos.close();
		fos.close();
	}

	/**
	 * * 生成公钥 *
	 * 
	 * @param modulus *
	 * @param publicExponent *
	 * @return RSAPublicKey *
	 * @throws Exception
	 */
	public static RSAPublicKey generateRSAPublicKey(byte[] modulus,
			byte[] publicExponent) throws Exception {
		KeyFactory keyFac = null;
		try {
			keyFac = KeyFactory.getInstance("RSA",
					new org.bouncycastle.jce.provider.BouncyCastleProvider());
		} catch (NoSuchAlgorithmException ex) {
			throw new Exception(ex.getMessage());
		}

		RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(
				modulus), new BigInteger(publicExponent));
		try {
			return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);
		} catch (InvalidKeySpecException ex) {
			throw new Exception(ex.getMessage());
		}
	}

	/**
	 * * 生成私钥 *
	 * 
	 * @param modulus *
	 * @param privateExponent *
	 * @return RSAPrivateKey *
	 * @throws Exception
	 */
	public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus,
			byte[] privateExponent) throws Exception {
		KeyFactory keyFac = null;
		try {
			keyFac = KeyFactory.getInstance("RSA",
					new org.bouncycastle.jce.provider.BouncyCastleProvider());
		} catch (NoSuchAlgorithmException ex) {
			throw new Exception(ex.getMessage());
		}

		RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(
				modulus), new BigInteger(privateExponent));
		try {
			return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
		} catch (InvalidKeySpecException ex) {
			throw new Exception(ex.getMessage());
		}
	}

	/**
	 * 加密的方法
	 * @throws IOException 
	 * @throws NoSuchPaddingException 
	 * @throws NoSuchAlgorithmException 
	 */
	private static String encrypt(PublicKey pk,String source) throws Exception{

		Cipher cipher = Cipher.getInstance("RSA",new org.bouncycastle.jce.provider.BouncyCastleProvider());
		cipher.init(Cipher.ENCRYPT_MODE, pk);
		byte[] sbt = source.getBytes();
		byte[] epByte = cipher.doFinal(sbt);
		BASE64Encoder encoder = new BASE64Encoder();
		String epStr = encoder.encode(epByte);
		return epStr;

	}
	private static String encrypt1(PublicKey pk,String source) throws Exception{
		Cipher cipher = Cipher.getInstance("RSA",new org.bouncycastle.jce.provider.BouncyCastleProvider());
		cipher.init(Cipher.ENCRYPT_MODE, pk);
		byte[] s = source.getBytes();
		byte[] en_s = cipher.doFinal(s);
		return new String(Hex.encode(en_s));

	}
	/**
	 * 解密的方法
	 * @throws Exception
	 */
	public static String decrypt(PrivateKey pk,String source) throws Exception {

		/** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
		Cipher cipher = Cipher.getInstance("RSA",new org.bouncycastle.jce.provider.BouncyCastleProvider());
		cipher.init(Cipher.DECRYPT_MODE, pk);
		BASE64Decoder decoder = new BASE64Decoder();
		byte[] b1 = decoder.decodeBuffer(source);
		/** 执行解密操作 */
		byte[] b = cipher.doFinal(b1);
		return new String(b);
	}
	public static String decrypt1(PrivateKey pk,String source) throws Exception {

		/** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
		Cipher cipher = Cipher.getInstance("RSA",new org.bouncycastle.jce.provider.BouncyCastleProvider());
		cipher.init(Cipher.DECRYPT_MODE, pk);
		/** 执行解密操作 */
		byte[] b = cipher.doFinal(Hex.decode(source));
		return new String(b);
	}
	public static void main(String[] args) throws Exception {
		String s = "1-Test-我";
		String en_s = encrypt1(getKeyPair().getPublic(), s);
		System.out.println("----------------分割线--------------------------");
		System.out.println("加密之后：");
		System.out.println(en_s);
		
		System.out.println("----------------分割线--------------------------");
		String de_s = decrypt1(getKeyPair().getPrivate(),en_s);  
        System.out.println("还原密文："); 
        System.out.println(de_s);
	}
}

Have a nice day~