RSA非对称算法Java工具类RSAUtil

RSA非对称算法Java工具类RSAUtil（公钥和私钥需要自行生成）

import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 * RSA非对称算法
 *
 * @author chenxy
 */
public final class RSAUtil {

	/**
	 * 私钥解密
	 *
	 * @param data       需解密的数据
	 * @param privateKey 私钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(privateKey);
		PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key key = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, key);
		return cipher.doFinal(data);
	}

	/**
	 * 公钥解密
	 *
	 * @param data      需解密的数据
	 * @param publicKey 公钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] data, String publicKey) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(publicKey);
		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key key = keyFactory.generatePublic(x509EncodedKeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, key);
		return cipher.doFinal(data);
	}

	/**
	 * 私钥加密
	 *
	 * @param data       需加密的数据
	 * @param privateKey 私钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(privateKey);
		PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key key = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, key);
		return cipher.doFinal(data);
	}

	/**
	 * 公钥加密
	 *
	 * @param data      需加密的数据
	 * @param publicKey 公钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(publicKey);
		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key key = keyFactory.generatePublic(x509EncodedKeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, key);
		return cipher.doFinal(data);
	}

	/**
	 * 获取私钥
	 *
	 * @param keyMap 密钥Map
	 * @return
	 * @throws Exception
	 */
	public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
		Key key = (Key) keyMap.get("PrivateKey");
		return new BASE64Encoder().encode(key.getEncoded());
	}

	/**
	 * 获取公钥
	 *
	 * @param keyMap 密钥Map
	 * @return
	 * @throws Exception
	 */
	public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
		Key key = (Key) keyMap.get("PublicKey");
		return new BASE64Encoder().encode(key.getEncoded());
	}

	/**
	 * 初始化密钥
	 *
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> initKey() throws Exception {
		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
		keyPairGenerator.initialize(1024);
		KeyPair keyPair = keyPairGenerator.generateKeyPair();
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
		Map<String, Object> keyMap = new HashMap<String, Object>(2);
		keyMap.put("PublicKey", publicKey);
		keyMap.put("PrivateKey", privateKey);
		return keyMap;
	}

	public static void main(String[] args) {
		try {
			Map<String, Object> map = initKey();
			String gy = getPublicKey(map);
			String sy = getPrivateKey(map);
			System.out.println(gy);
			System.out.println(sy);
			String context = "fasdfsdfsdf";
			byte[] enContext = encryptByPrivateKey(context.getBytes(StandardCharsets.UTF_8), sy);
			byte[] deContext = decryptByPublicKey(enContext, gy);
			System.out.println(AESUtil.parseByte2HexStr(enContext));
			System.out.println(new String(deContext));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	/**
	 * 私钥签名
	 *
	 * @param data       需签名的数据
	 * @param privateKey 私钥
	 * @return
	 * @throws Exception
	 */
	public static String signByPrivateKey(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(privateKey);
		PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PrivateKey key = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
		Signature signature = Signature.getInstance("MD5withRSA");
		signature.initSign(key);
		signature.update(data);
		return new BASE64Encoder().encode(signature.sign());
	}

	/**
	 * 公钥校验
	 *
	 * @param data      需校验的数据
	 * @param publicKey 公钥
	 * @param sign      签名
	 * @return
	 * @throws Exception
	 */
	public static boolean verifyByPublicKey(byte[] data, String publicKey, String sign) throws Exception {
		byte[] keyBytes = new BASE64Decoder().decodeBuffer(publicKey);
		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		PublicKey key = keyFactory.generatePublic(x509EncodedKeySpec);
		Signature signature = Signature.getInstance("MD5withRSA");
		signature.initVerify(key);
		signature.update(data);
		return signature.verify(new BASE64Decoder().decodeBuffer(sign));
	}

	private RSAUtil() {
	}

}