[Java知识库]RSA+AES对数据加密

由于RSA加密得字符串长度和密钥长度有关，所以一般结合aes加密使用

加密方式如图

解密方式如图

?具体java实现如下

RSAUtils.java

package com.utils.sign;

import com.constant.Constants;

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.ArrayList;
import java.util.List;
import javax.crypto.Cipher;

/**
 * RSA加密类
 * 不同长度的密钥对应可以加密不同最大长度的原文,2048就对应245
 */
public class RSAUtils {
    /**
     * 密钥长度 于原文长度对应 长度越长速度越慢
     */
    private final static int KEY_SIZE = 2048;

    /**
     * 随机生成密钥对
     */
    public static List<String> genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器
        keyPairGen.initialize(KEY_SIZE, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        // 得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = Base64.encode(publicKey.getEncoded());
        // 得到私钥字符串
        String privateKeyString = Base64.encode(privateKey.getEncoded());
        // 将公钥和私钥保存到
        List<String> keyList = new ArrayList<>(2);
        //0表示公钥
        keyList.add(publicKeyString);
        //1表示私钥
        keyList.add(privateKeyString);
        return keyList;
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decode(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        return Base64.encode(cipher.doFinal(str.getBytes("UTF-8")));
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 明文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.decode(str);
        //base64编码的私钥
        byte[] decoded = Base64.decode(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        return new String(cipher.doFinal(inputByte));
    }

    public static void main(String[] args) throws Exception {
        long temp;
        //生成公钥和私钥
//        List<String> keys = genKeyPair();
//        //加密字符串
//        System.out.println("公钥:" + keys.get(0));
//        System.out.println("私钥:" + keys.get(1));
        //System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
        //客户id + 授权时间 + 所用模块
        String message = "admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123admin123";
        System.out.println("原文:" + message);
        temp = System.currentTimeMillis();
        //通过原文，和公钥加密。
        String messageEn = encrypt(message, Constants.PUBLIC_KEY);
        System.out.println("密文:" + messageEn);
        System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
        temp = System.currentTimeMillis();
        //通过密文，和私钥解密。
        String messageDe = decrypt(messageEn, Constants.PRIVATE_KEY);
        System.out.println("解密:" + messageDe);
        System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
    }
}

AesUtils.java

package com.utils.sign;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Base64;

/**
 * AES工具类
 */
public class AesUtils {
    private static final String CHARSET = "utf-8";

    /**
     * 生成随机密钥
     * @param keySize 密钥大小推荐128 256
     * @return
     * @throws NoSuchAlgorithmException
     */
    public static String generateSecret(int keySize) throws NoSuchAlgorithmException {
        KeyGenerator generator = KeyGenerator.getInstance("AES");
        generator.init(keySize, new SecureRandom());
        SecretKey key = generator.generateKey();
        return byteToHexString(key.getEncoded());
    }

    public static String encrypt(String strToEncrypt, String secret) throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        SecretKeySpec secretKey = getKey(secret);
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes("UTF-8")));
    }

    public static String decrypt(String strToDecrypt, String secret) throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        SecretKeySpec secretKey = getKey(secret);
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
    }
    private static SecretKeySpec getKey(String myKey) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        byte[] key = myKey.getBytes(CHARSET);
        MessageDigest sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
        key = Arrays.copyOf(key, 16);
        return new SecretKeySpec(key, "AES");
    }
    /**
     * byte数组转化为16进制字符串
     * @param bytes
     * @return
     */
    private static String byteToHexString(byte[] bytes){
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) {
            String strHex=Integer.toHexString(bytes[i]);
            if(strHex.length() > 3){
                sb.append(strHex.substring(6));
            } else {
                if(strHex.length() < 2){
                    sb.append("0" + strHex);
                } else {
                    sb.append(strHex);
                }
            }
        }
        return  sb.toString();
    }

    public static void main(String[] args) throws NoSuchAlgorithmException, IllegalBlockSizeException, InvalidKeyException, BadPaddingException, NoSuchPaddingException, UnsupportedEncodingException {
        String key = generateSecret(256);
        String enData = encrypt("你好测试hello", key);
        System.out.println(enData);
        String deData = decrypt(enData, key);
        System.out.println(deData);
        enData = encrypt("你好测试", key);
        System.out.println(enData);
        deData = decrypt(enData, key);
        System.out.println(deData);
    }
}

CryptUtil.java

package com.utils.sign;


import com.constant.Constants;
/**
 * 使用rsa和aes加密算法对数据进行加解密
 * 加密得数据逗号分割，
 *      前部分为用rsa加密得aes密钥，后部分为aes用前面密钥加密得字符串
 */
public class CryptUtil {
    private static String split = ",";
    private static Integer aesKeySize = 128;


    public static String encryptData(String data) throws Exception{
        return encryptData(data,Constants.PUBLIC_KEY);
    }
    public static String decryptData(String data) throws Exception{
        return decryptData(data,Constants.PRIVATE_KEY);
    }
    /**
     * 公钥加密
     * @param data
     * @param publicInfoStr
     * @return 使用RSA加密AES的key,使用AES加密数据
     */
    private static String encryptData(String data, String publicInfoStr) throws Exception{
        // 随机生成AES key
        String aesKey = AesUtils.generateSecret(aesKeySize);
        // 使用AES加密数据
        String enData = AesUtils.encrypt(data, aesKey);
        // 使用RSA加密AES key
        String enAesKey = RSAUtils.encrypt(aesKey, publicInfoStr);
        return enAesKey + split + enData;
    }

    /**
     * 私钥解密
     * @param data 逗号分割:'使用RSA加密AES的key,使用AES加密数据'
     * @param privateInfoStr
     * @return 解密后的数据
     */
    private static String decryptData(String data, String privateInfoStr) throws Exception{
        // 拆解数据
        String[] dataArr = data.split(split);
        if(dataArr.length != 2){
            throw new IllegalArgumentException("data必须逗号分割:'使用RSA加密AES的key,使用AES加密数据'");
        }
        // 使用RSA解密AES key
        String aesKey = RSAUtils.decrypt(dataArr[0], privateInfoStr);
        // 使用AES解密数据
        return AesUtils.decrypt(dataArr[1], aesKey);
    }
    public static void main(String[] args) throws Exception{
//         生成公钥和私钥
//        List<String> keys = RSAUtils.genKeyPair();
//        //加密字符串
//        System.out.println("公钥:" + keys.get(0));
//        System.out.println("私钥:" + keys.get(1));
        long temp;
        temp = System.currentTimeMillis();
        String enStr = encryptData("你好测试测试测试测试你好测试你好测试测试");
        System.out.println(enStr);
        System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
        temp = System.currentTimeMillis();
        String deStr = decryptData(enStr);
        System.out.println(deStr);
        System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
    }

}

最终调用CryptUtil.encryptData(str)加密字符串,CryptUtil.decryptData(str)解密字符串

rsa得公钥私钥需要使用RSAUtils.genKeyPair()生成，并保存在代码中

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