package com.zcloud.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;

/**
 * RSA公钥/私钥/签名工具包
 * <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>
 *
 */
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 = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDUoHAavCikaZxjlDM6Km8cX+ye78F4oF39AcEfnE1p2Yn9pJ9WFxYZ4Vkh6F8SKMi7k4nYsKceqB1RwG996SvHQ5C3pM3nbXCP4K15ad6QhN4a7lzlbLhiJcyIKszvvK8ncUDw8mVQ0j/2mwxv05yH6LN9OKU6Hzm1ninpWeE+awIDAQAB\n";

    /** */
    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "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";

    /** */
    /**
     * 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>
     * 获取私钥
     * </p>
     *
     * @param keyMap
     *            密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey()  {
        return PRIVATE_KEY;
    }

    /** */
    /**
     * <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());
    }

    /** */
    /**
     * <p>
     * 获取公钥
     * </p>
     * @return
     * @throws Exception
     */
    public static String getPublicKey() throws Exception {
        return PUBLIC_KEY;
    }

    /**
     * java端公钥加密
     */
    public static String encryptedDataOnJava(String data, String PUBLICKEY) {
        try {
            data = Base64Utils.encode(encryptByPublicKey(data.getBytes(), PUBLICKEY));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return data;
    }

    /**
     * java端私钥解密
     */
    public static String decryptDataOnJava(String data, String PRIVATEKEY) {
        String temp = "";
        try {
            byte[] rs = Base64Utils.decode(data);
            temp = new String(RSAUtils.decryptByPrivateKey(rs, PRIVATEKEY),"UTF-8"); //以utf-8的方式生成字符串

        } catch (Exception e) {
            e.printStackTrace();
        }
        return temp;
    }

    public static void main(String[] args) {
        Map<String, Object> keyMap = null;
        try {
            keyMap = RSAUtils.genKeyPair();
            String publicKey = RSAUtils.getPublicKey(keyMap);
            String privateKey = RSAUtils.getPrivateKey(keyMap);
            System.err.println("公钥: \n\r" + publicKey);
            System.err.println("私钥： \n\r" + privateKey);
//            公钥:
//            MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDE8aNkz3X5f96bW2EJ3fRQsEmtgrIzLSCSJZLf1WBay0ihEideK45md5UZIFB6HSWwBaKD4z1uAMdt5esn0AIvrQS8+nlnB+Fohzxg7yY2ooDLP2az0WVKzepbeg8igq+jflUh7/+rvndiJAnv+mnMbibFqhYsDAJ3Zq82FkOeXQIDAQAB
//            私钥：
//            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

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}