package com.zhgd.xmgl.util;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
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;
 
/** *//**
 * <p>
 * RSA公钥/私钥/签名工具包
 * </p>
 * <p>
 * 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
 * </p>
 * <p>
 * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 * </p>
 * 
 * @author IceWee
 * @date 2012-4-26
 * @version 1.0
 */
public class RSAUtils {
 
    /** *//**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";
    
    /** *//**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
 
    /** *//**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";
    
    /** *//**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";
    
    /** *//**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;
    
    /** *//**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 128;
 
    /** *//**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     * 
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }
    
    /** *//**
     * <p>
     * 用私钥对信息生成数字签名
     * </p>
     * 
     * @param data 已加密数据
     * @param privateKey 私钥(BASE64编码)
     * 
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return Base64Utils.encode(signature.sign());
    }
 
    /** *//**
     * <p>
     * 校验数字签名
     * </p>
     * 
     * @param data 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @param sign 数字签名
     * 
     * @return
     * @throws Exception
     * 
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(Base64Utils.decode(sign));
    }
 
    /** *//**
     * <P>
     * 私钥解密
     * </p>
     * 
     * @param encryptedData 已加密数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }
 
    /** *//**
     * <p>
     * 公钥解密
     * </p>
     * 
     * @param encryptedData 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }
 
    /** *//**
     * <p>
     * 公钥加密
     * </p>
     * 
     * @param data 源数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }
 
    /** *//**
     * <p>
     * 私钥加密
     * </p>
     * 
     * @param data 源数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }
 
    /** *//**
     * <p>
     * 获取私钥
     * </p>
     * 
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return Base64Utils.encode(key.getEncoded());
    }
 
    /** *//**
     * <p>
     * 获取公钥
     * </p>
     * 
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return Base64Utils.encode(key.getEncoded());
    }
    
    public static void main(String[] args) throws Exception {
		//生成公钥和私钥
		//genKeyPair();
    	/*Map<String, Object> keyMap = RSAUtils.genKeyPair();
    	String publicKey = RSAUtils.getPublicKey(keyMap);
		log.info("随机生成的公钥为:" + publicKey);
		String privateKey = RSAUtils.getPrivateKey(keyMap);
		log.info("随机生成的私钥为:" + privateKey);
		MsgAccessTokenRequestBean accessToken = new MsgAccessTokenRequestBean();
		accessToken.setAppSecret("glggqwstf12lsdqw");
		byte[] ras = RSAUtils.encryptByPublicKey(JSON.toJSONString(accessToken).getBytes(), publicKey);
		log.info("加密字符串为:" + new String(ras));
		byte[] ras1 = RSAUtils.decryptByPrivateKey(ras, privateKey);
		log.info("解密字符串为:" + new String(ras1));*/
		//加密字符串
		//String message = "{\"Body\":{\"phone\":\"13617025246\",\"token\":\"bb8c55a4c8239bae4b3da7733be94e02\",\"cardId\":\"360402********2513\",\"cardName\":\"张涛\"}}";
		//String message = "{\"ph\":\"13617025246\",\"tk\":\"bb8c55a4c8239bae4b3da7733be94e02\",\"Id\":\"360402********2513\",\"nm\":\"张涛已然\"}";
		//{"Body":{"phone":"13617025246","token":"bb8c55a4c8239bae4b3da7733be94e02","cardId":"360402********2513","cardName":"张涛"}}
		
//		String messageEn = encrypt(message,RsaConfFileTool.getPublicKey());
//		log.info(message + "\t加密后的字符串为:" + messageEn);
//		String messageDe = decrypt(messageEn,RsaConfFileTool.getSecretKey());
//		log.info("还原后的字符串为:" + messageDe);
	}

}