RSAUtil - RSA加解密工具类

Posted 2020-11-27 wcis

工具类

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
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;


public class RSAUtil {

	/**
	 * 随机生成密钥对
	 * 
	 * @throws NoSuchAlgorithmException
	 */
	public static KV<String, String> generateKeyPair() throws NoSuchAlgorithmException {
		// KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
		KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
		// 初始化密钥对生成器，密钥大小为96-1024位
		keyPairGen.initialize(1024, new SecureRandom());
		// 生成一个密钥对，保存在keyPair中
		KeyPair keyPair = keyPairGen.generateKeyPair();
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 得到私钥
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 得到公钥
		String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
		// 得到私钥字符串
		String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
		return new KV<String, String>(publicKeyString, privateKeyString);
	}

	/**
	 * RSA公钥加密
	 * 
	 * @param str
	 *            加密字符串
	 * @param publicKey
	 *            公钥
	 * @return 密文
	 * @throws Exception
	 *             加密过程中的异常信息
	 */
	public static String encrypt(String str, String publicKey) throws Exception {
		// base64编码的公钥
		byte[] decoded = Base64.decodeBase64(publicKey);
		RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA")
				.generatePublic(new X509EncodedKeySpec(decoded));
		// RSA加密
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.ENCRYPT_MODE, pubKey);
		String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
		return outStr;
	}

	/**
	 * RSA私钥解密
	 * 
	 * @param str
	 *            加密字符串
	 * @param privateKey
	 *            私钥
	 * @return 铭文
	 * @throws Exception
	 *             解密过程中的异常信息
	 */
	public static String decrypt(String str, String privateKey) throws Exception {
		// 64位解码加密后的字符串
		byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
		// base64编码的私钥
		byte[] decoded = Base64.decodeBase64(privateKey);
		RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA")
				.generatePrivate(new PKCS8EncodedKeySpec(decoded));
		// RSA解密
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, priKey);
		String outStr = new String(cipher.doFinal(inputByte));
		return outStr;
	}
	
	private static void testBase64() throws Exception {
		String content = "{"name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming"}";
		content = "7652344555";
		byte[] bytes1 = Base64.encodeBase64(content.getBytes("UTF-8"));
		String result = new String(bytes1,"UTF-8");
		System.out.println(result);
	}

	public static void main(String[] args) throws Exception {
		KV<String, String> kv = RSAUtil.generateKeyPair();
		
		String content = "{"name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming","name":"xiaoming"}";
		content = "ABCDEFGHI";
		
		String totext = RSAUtil.encrypt(content, kv.getKey());
		System.out.println(totext);
		String tedxtResult = RSAUtil.decrypt(totext, kv.getValue());
		System.out.println(tedxtResult);
		System.out.println("-------------------------------");
		testBase64() ;
	}

}