生成RSA公私鑰

代碼：

 

import com.alibaba.fastjson.JSON;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

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.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

import javax.crypto.Cipher;

/**
 * <p>
 * RSA公鑰/私鑰/簽名工具包
 * </p>
 * <p>
 * 羅納德·李維斯特（Ron [R]ivest）、阿迪·薩莫爾（Adi [S]hamir）和倫納德·阿德曼（Leonard [A]dleman）
 * </p>
 * <p>
 * 字符串格式的密鑰在未在特殊說明情況下都為BASE64編碼格式<br/>
 * 由於非對稱加密速度極其緩慢，一般文件不使用它來加密而是使用對稱加密，<br/>
 * 非對稱加密算法可以用來對對稱加密的密鑰加密，這樣保證密鑰的安全也就保證了數據的安全
 * </p>
 *
 * @author Joe
 * @date 2019-4-15
 * @version 1.0
 */
public class RSAXUtils {

    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /**
     * 簽名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /**
     * 獲取公鑰的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /**
     * 獲取私鑰的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>
     * 生成密鑰對(公鑰和私鑰)
     * </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>
     * 用私鑰對信息生成數字簽名
     * </p>
     *
     * @param data 已加密數據
     * @param privateKey 私鑰(BASE64編碼)
     *
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = 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 encode(signature.sign());
    }

    /**
     * <p>
     * 校驗數字簽名
     * </p>
     *
     * @param data 已加密數據
     * @param publicKey 公鑰(BASE64編碼)
     * @param sign 數字簽名
     *
     * @return
     * @throws Exception
     *
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        byte[] keyBytes = 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(decode(sign));
    }

    /**
     * <P>
     * 私鑰解密
     * </p>
     *
     * @param encryptedData 已加密數據
     * @param privateKey 私鑰(BASE64編碼)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = 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;
        // 對數據分段解密
        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>
     * 公鑰解密
     * </p>
     *
     * @param encryptedData 已加密數據
     * @param publicKey 公鑰(BASE64編碼)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
            throws Exception {
        byte[] keyBytes = 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;
        // 對數據分段解密
        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>
     * 公鑰加密
     * </p>
     *
     * @param data 源數據
     * @param publicKey 公鑰(BASE64編碼)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 對數據加密
        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;
        // 對數據分段加密
        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>
     * 私鑰加密
     * </p>
     *
     * @param data 源數據
     * @param privateKey 私鑰(BASE64編碼)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = 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;
        // 對數據分段加密
        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>
     * 獲取私鑰
     * </p>
     *
     * @param keyMap 密鑰對
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return encode(key.getEncoded());
    }

    /**
     * <p>
     * 獲取公鑰
     * </p>
     *
     * @param keyMap 密鑰對
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return encode(key.getEncoded());
    }

    /**
     * <p>
     * BASE64字符串解碼為二進制數據
     * </p>
     *
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
        return new BASE64Decoder().decodeBuffer(base64);
    }

    /**
     * <p>
     * 二進制數據編碼為BASE64字符串
     * </p>
     *
     * @param bytes
     * @return
     * @throws Exception
     */
    public static String encode(byte[] bytes) {
        return new String(new BASE64Encoder().encode(bytes));
    }

    /**
     * 按key進行正序排列，之間以&相連
     * <功能描述>
     * @param params
     * @return
     */
    public static String getSortParams(Map<String, Object> params) {
        Map<String, Object> map = new TreeMap<>(Comparator.naturalOrder());
        map.putAll(params);

        StringBuffer stringBuffer = new StringBuffer();
        map.forEach((k,v)-> stringBuffer.append(k).append("=").append(v).append("&"));

        String str = stringBuffer.toString();

        if(str.length() > 0){
            str = str.substring(0, str.length()-1);
        }
        return str;
    }

    public static void main(String[] args) throws Exception {
        baseTest();
        // signDemo();
    }

    /**
     * 基本測試
     * @throws Exception
     */
    private static void baseTest() throws Exception{
        Map<String, Object> keyPair = genKeyPair();
        // 公鑰
        String publicKey = getPublicKey(keyPair);
        System.out.println("公鑰-------------"+publicKey);

        // 私鑰
        String privateKey = getPrivateKey(keyPair);
        System.out.println("私鑰-------------"+privateKey);

        String source = "這是一行沒有任何意義的文字，你看完了等於沒看，不是嗎？";

        // 簽名
        String sign = RSAXUtils.sign(source.getBytes(), privateKey);
        System.err.println("簽名-------------" + sign);

        // 驗簽
        boolean status = RSAXUtils.verify(source.getBytes(), publicKey, sign);
        System.err.println("驗證結果-------------" + status);

    }

    /**
     * 驗簽完整demo
     * @throws Exception
     */
    private static void signDemo() throws Exception{
        Map<String, Object> keyPair = genKeyPair();
        // 公鑰
        String publicKey = getPublicKey(keyPair);
        System.out.println("公鑰-------------"+publicKey);

        // 私鑰
        String privateKey = getPrivateKey(keyPair);
        System.out.println("私鑰-------------"+privateKey);

        Map<String, Object> bizData = new HashMap<>();
        bizData.put("autopay_flag", 1);
        bizData.put("order_no", "123456789");
        bizData.put("order_status", 200);
        bizData.put("change_card_flag", 1);
        bizData.put("withdraw_flag", 0);
        Map<String,Object> params = new HashMap<>();
        params.put("sign_type","RSA");
        params.put("app_id","test");
        params.put("version","1.0.0");
        params.put("call","feedbackOrderStatus");
        params.put("timestamp",String.valueOf(System.currentTimeMillis()));
        params.put("biz_data", JSON.toJSONString(bizData));

        // 排序並拼接成字符串
        String paramsStr = getSortParams(params);
        System.out.println("排序並拼接成字符串: " + paramsStr);

        // 簽名
        long begin = System.currentTimeMillis();
        System.err.println("簽名-------------begin=" + begin);
        String sign = RSAXUtils.sign(paramsStr.getBytes(), privateKey);
        long end = System.currentTimeMillis();
        System.err.println("簽名-------------" + sign );
        System.err.println("簽名-------------花費時間=" + (end - begin) + "ms");

        params.put("sign", sign);

        System.out.println("post請求參數------------" + JSON.toJSONString(params));

        // 開始驗簽-----------------------------------------

        Map<String,Object> params2 = JSON.parseObject(JSON.toJSONString(params), Map.class);

        // 驗簽需要去除sign
        params2.remove("sign");

        // 排序並拼接成字符串
        String paramsStr2 = getSortParams(params2);

        // 驗簽
        boolean status = RSAXUtils.verify(paramsStr2.getBytes(), publicKey, sign);
        System.err.println("驗證結果-------------" + status);
    }
}