RSA 非对称加密传输

RSA 介绍

RSA（Rivest-Shamir-Adleman）是一种非对称加密算法，它是目前最广泛使用的公钥加密算法之一。RSA算法是由三位密码学家（Ron Rivest、Adi Shamir、Leonard Adleman）在1977年提出的。

经典的非对称加密算法：非对称加密算法中，有两个密钥：公钥和私钥。它们是一对，如果用公钥进行加密，只有用对应的私钥才能解密；如果用私钥进行加密，只有用对应的公钥才能解密。

密钥对生成

密钥对生成网址：http://web.chacuo.net/netrsakeypair

前端 Jsencrypt 安装

（一）Vue、uniapp：npm install jsencrypt
（二）引入：import JSEncrypt from ‘../node_modules/jsencrypt/bin/jsencrypt.js’

前端创建 Jsencrypt.js 文件

创建好此文件后，则可以在需要加密、解密的页面中引入，使用对应方法即可。

import JSEncrypt from 'jsencrypt/bin/jsencrypt'

// 密钥对生成 http://web.chacuo.net/netrsakeypair

const publicKey = 'xxxx'

const privateKey = 'xxxx'

// 加密
export function encrypt(txt) {
  const encryptor = new JSEncrypt()
  encryptor.setPublicKey(publicKey) // 设置公钥
  return encryptor.encrypt(txt) // 对需要加密的数据进行加密
}

// 解密
export function decrypt(txt) {
  const encryptor = new JSEncrypt()
  encryptor.setPrivateKey(privateKey)
  return encryptor.decrypt(txt)
}

后端依赖

版本自行选择

<dependency>
    <groupId>cn.hutoolgroupId>
    <artifactId>hutool-allartifactId>
    <version>5.4.4version>
dependency>
<dependency>
    <groupId>org.apache.commonsgroupId>
    <artifactId>commons-lang3artifactId>
    <version>3.12.0version>
dependency>
<dependency>
    <groupId>commons-collectionsgroupId>
    <artifactId>commons-collectionsartifactId>
    <version>3.2.2version>
dependency>
<dependency>
    <groupId>commons-codecgroupId>
    <artifactId>commons-codecartifactId>
dependency>

创建 Java RSA工具类

配置的密钥对必须和前端Jsencrypt.js中密钥对一样 ！！！

/**
 * RSA工具类
 */
public class RSAUtils {

    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA";
    /**
     *密钥对 必须和前端一样！！！
     */
    public static final String publicKey = "XXX";
    public static final String privateKey = "xxxx";

    public static Map<String, String> createKeys(int keySize){
        //为RSA算法创建一个KeyPairGenerator对象
        KeyPairGenerator kpg;
        try{
            kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
        }catch(NoSuchAlgorithmException e){
            throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
        }

        //初始化KeyPairGenerator对象,密钥长度
        kpg.initialize(keySize);
        //生成密匙对
        KeyPair keyPair = kpg.generateKeyPair();
        //得到公钥
        Key publicKey = keyPair.getPublic();
        String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
        //得到私钥
        Key privateKey = keyPair.getPrivate();
        System.out.println("私钥格式:"+privateKey.getFormat());
        String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
        Map<String, String> keyPairMap = new HashMap<String, String>();
        keyPairMap.put("publicKey", publicKeyStr);
        keyPairMap.put("privateKey", privateKeyStr);

        return keyPairMap;
    }

    /**
     * 得到公钥
     * @param publicKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        //通过X509编码的Key指令获得公钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }

    /**
     * 得到私钥
     * @param privateKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        //通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }

    /**
     * 公钥加密
     * @param data
     * @return
     */
    public static String publicEncrypt(String data){
        try{
            RSAPublicKey publicKey = getPublicKey(RSAUtils.publicKey);
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥解密
     * @param data
     * @return
     */

    public static String privateDecrypt(String data){
        try{
            RSAPrivateKey privateKey = getPrivateKey(RSAUtils.privateKey);
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥加密
     * @param data
     * @return
     */

    public static String privateEncrypt(String data){
        try{
            RSAPrivateKey privateKey = getPrivateKey(RSAUtils.privateKey);
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 公钥解密
     * @param data
     * @return
     */

    public static String publicDecrypt(String data){
        try{
            RSAPublicKey publicKey = getPublicKey(RSAUtils.publicKey);
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){
        int maxBlock = 0;
        if(opmode == Cipher.DECRYPT_MODE){
            maxBlock = keySize / 8;
        }else{
            maxBlock = keySize / 8 - 11;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] buff;
        int i = 0;
        try{
            while(datas.length > offSet){
                if(datas.length-offSet > maxBlock){
                    buff = cipher.doFinal(datas, offSet, maxBlock);
                }else{
                    buff = cipher.doFinal(datas, offSet, datas.length-offSet);
                }
                out.write(buff, 0, buff.length);
                i++;
                offSet = i * maxBlock;
            }
        }catch(Exception e){
            throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
        return resultDatas;
    }

}