RSA 工具类

package com.box.common.core.rsa;

import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.SerializerFeature;
import lombok.extern.slf4j.Slf4j;
import sun.misc.BASE64Decoder;

import java.io.ByteArrayOutputStream;
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;


/**
 * RSA签名验签类
 */
@Slf4j
public class RSASignatureUtil {

    /**
     * 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) {
        try {
            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());
        }catch (Exception e){
            e.printStackTrace();
        }
       return "";
    }

    /**
     * <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) {
        try {
            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));
        } catch (Exception e) {
           log.error("验证签名错误",e);
        }
        return false;

    }

    /**
     * <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 String decryptByPrivateKey(String encryptedData, String privateKey)throws Exception{

        return new String(decryptByPrivateKey(Base64Utils.decode(encryptedData),privateKey));
    }
    private 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 String decryptByPublicKey(String encryptedData, String publicKey) throws Exception{

        return new String(decryptByPublicKey(Base64Utils.decode(encryptedData),publicKey));
    }
    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 String encryptByPublicKey(String data, String publicKey)throws Exception{
        return Base64Utils.encode(encryptByPublicKey(data.getBytes(),publicKey)).toString();
    }
    private 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 String encryptByPrivateKey(String data, String privateKey)
            throws Exception {
        return  Base64Utils.encode(encryptByPrivateKey(data.getBytes(),privateKey)).toString();
    }
    private 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) {

        JSONObject param = new JSONObject();
        param.put("deviceId", "12312973");
        param.put("offsetPage", "1");
        param.put("pageSize", "10");
        param.put("merchant_no","123456");

        System.out.println(JSONObject.toJSONString(param, SerializerFeature.SortField.MapSortField));


        try {

            /*
            Map<String, Object> keyMap = RSASignatureUtil.genKeyPair();
            String publicKey = RSASignatureUtil.getPublicKey(keyMap);
            String privateKey = RSASignatureUtil.getPrivateKey(keyMap);
            System.err.println("公钥: 

" + publicKey);
            System.err.println("私钥： 

" + privateKey);


            System.err.println("公钥加密——私钥解密");
            String source = "这是一行没有任何意义的文字，你看完了等于没看，不是吗？";
            System.out.println("
加密前文字：
" + source);

            String encodedData = RSASignatureUtil.encryptByPublicKey(source, publicKey);
            System.out.println("加密后文字：
" + encodedData);
            String decodedData = RSASignatureUtil.decryptByPrivateKey(encodedData, privateKey);
            System.out.println("解密后文字: 
" + decodedData);


            encodedData = RSASignatureUtil.encryptByPrivateKey(param.toJSONString(), privateKey);
            System.out.println("加密后：" + encodedData);
            decodedData = RSASignatureUtil.decryptByPublicKey(encodedData, publicKey);
            System.out.println("解密后：" + decodedData);
*/
            //公钥:
            String pu = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCseCw4mhuvsy1rdrf4NC2RdhFCiC/ngefjworjZnRTc83aD5bUH/H4ewYVvaTXT2/eIiN93+SL/UC9asLsRXxV9rG99TltWWtaVR3ATB7bYQkUw0O+7ogbP+nAbIPGiuWopOPoIlHuCdaJJ1argNd9Od88QQnM1gtdRFwP9YuXdQIDAQAB";

           // 私钥：
            String pr = "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";

            String aa ="";

            //System.out.println("aa:"+ RSASignatureUtil.decryptByPublicKey(aa, pr));
            String sign = RSASignatureUtil.sign(JSONObject.toJSONString(param, SerializerFeature.SortField.MapSortField).getBytes(), pr);
            System.err.println("签名：" + sign);
            boolean status = RSASignatureUtil.verify(JSONObject.toJSONString(param, SerializerFeature.SortField.MapSortField).getBytes(), pu, sign);
            System.err.println("签名验证结果：" + status);



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


    }
}