完整的RSA开发流程以及加解密Demo

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

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

public class RSACryptography {

	public static String data = "hello world";

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub

		KeyPair keyPair = genKeyPair(1024);

		// 获取公钥，并以base64格式打印出来
		PublicKey publicKey = keyPair.getPublic();
		System.out.println("公钥：" + new String(Base64.encodeBase64String(publicKey.getEncoded())));

		// 获取私钥，并以base64格式打印出来
		PrivateKey privateKey = keyPair.getPrivate();
		System.out.println("私钥：" + new String(Base64.encodeBase64String(privateKey.getEncoded())));

		// 公钥加密
		byte[] encryptedBytes = encrypt(data.getBytes(), publicKey);
		// System.out.println("加密后乱码："+ new String(encryptedBytes)); //打印出来是乱码

		String encoded = Base64.encodeBase64String(encryptedBytes); // Base64编码
		System.out.println("加密后_Base64编码：" + new String(encoded));

		// 私钥解密
		byte[] decryptedBytes = decrypt(encryptedBytes, privateKey);
		System.out.println("解密后：" + new String(decryptedBytes));
	}

	// 生成密钥对
	public static KeyPair genKeyPair(int keyLength) throws Exception {
		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
		keyPairGenerator.initialize(1024);
		return keyPairGenerator.generateKeyPair();
	}

	// 公钥加密
	public static byte[] encrypt(byte[] content, PublicKey publicKey) throws Exception {
		Cipher cipher = Cipher.getInstance("RSA");// java默认"RSA"="RSA/ECB/PKCS1Padding"
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);
		return cipher.doFinal(content);
	}

	// 私钥解密
	public static byte[] decrypt(byte[] content, PrivateKey privateKey) throws Exception {
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, privateKey);
		return cipher.doFinal(content);
	}

	/**
	 * 字符串转为公钥
	 * 
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static PublicKey getPublicKey(String key) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(key);
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PublicKey publicKey = keyFactory.generatePublic(keySpec);
		return publicKey;
	}

	/**
	 * 字符串转私钥
	 * 
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static PrivateKey getPrivateKey(String key) throws Exception {

		byte[] keyBytes = Base64.decodeBase64(key);
		PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
		return privateKey;
	}

}