Java实现RSA加解密

妖狐艹你老母 2024-03-22 22:17 93阅读 0赞

## Java实现RSA加解密 ##

### 需要引入的依赖 ###

<dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
                <version>5.7.8</version>
            </dependency>

### RSA密钥对生成工具类 ###

package cn.demo.rsa;
    
    import cn.hutool.core.collection.CollUtil;
    import cn.hutool.core.io.FileUtil;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.nio.file.Files;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.NoSuchAlgorithmException;
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.util.ArrayList;
    import java.util.Base64;
    import java.util.HashMap;
    import java.util.List;
    
    public class RSAKeyGenUtil {
        
    
        /**
         * 密钥大小，单位bit
         */
        private static final int KEY_SIZE = 1024;
    
        private static HashMap<String, String> createBase64RSAKey() throws NoSuchAlgorithmException {
        
    
            HashMap<String, String> ssMap = new HashMap<>();
    
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(KEY_SIZE);
    
            //生成密钥对
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            RSAPublicKey pubKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey priKey = (RSAPrivateKey) keyPair.getPrivate();
    
            String pub = new String(Base64.getEncoder().encode(pubKey.getEncoded()));
            String pri = new String(Base64.getEncoder().encode(priKey.getEncoded()));
            System.out.println("公钥：" + pub);
            System.out.println("私钥：" + pri);
    
            ssMap.put("publicKey",pub);
            ssMap.put("privateKey",pri);
            return ssMap;
        }
    
        /**
         * 生成的公钥和私钥文件，最好放到项目的classpath下，以便app读取
         */
        private static void  genRSAKeyFile(){
        
            HashMap<String, String> ssMap = new HashMap<>();
            try {
        
                ssMap = createBase64RSAKey();
            } catch (NoSuchAlgorithmException e) {
        
                e.printStackTrace();
            }
            if (CollUtil.isNotEmpty(ssMap)){
        
                File pubKeyFile = FileUtil.writeBytes(ssMap.get("publicKey").getBytes(),
                        "D:/rsa2/rsa_public.key");
                System.out.println(pubKeyFile.getAbsolutePath());
    
                File priKeyFile = FileUtil.writeBytes(ssMap.get("privateKey").getBytes(),
                        "D:/rsa2/rsa_private.key");
                System.out.println(priKeyFile.getAbsolutePath());
    
            }
    
        }
    
        public static void main(String[] args) {
        
            genRSAKeyFile();
        }
    
    
    
    }

### RSA加解密工具类 ###

package cn.demo.rsa;
    
    import cn.hutool.core.io.FileUtil;
    
    import javax.crypto.Cipher;
    import java.io.File;
    import java.nio.charset.StandardCharsets;
    import java.security.KeyFactory;
    import java.security.PrivateKey;
    import java.security.PublicKey;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    import java.util.Base64;
    
    public class RSAjjmUtils {
        
    
        /**
         * rsa加密
         * @param yw  原文
         * @param rsaPublicKeyFilePath  rsa公钥文件路径
         * @return 密文
         * @throws Exception
         */
        public static String encrypt(String yw,String rsaPublicKeyFilePath) throws Exception {
        
            String utf8StringPubk = FileUtil.readUtf8String(rsaPublicKeyFilePath);
            byte[] publicKeyBytes = utf8StringPubk.getBytes();
            X509EncodedKeySpec x =
                    new X509EncodedKeySpec(Base64.getDecoder().decode(publicKeyBytes));
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PublicKey pubKey = keyFactory.generatePublic(x);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, pubKey);
    
            byte[] result = cipher.doFinal(yw.getBytes(StandardCharsets.UTF_8));
            return Base64.getEncoder().encodeToString(result);
        }
    
    
        /**
         * rsa解密
         * @param mw  密文
         * @param rsaPrivateKeyFilePath rsa私钥文件路径
         * @return 原文
         * @throws Exception
         */
        public static String decrypt(String mw,String rsaPrivateKeyFilePath) throws Exception{
        
            String utf8StringPrik = FileUtil.readUtf8String(rsaPrivateKeyFilePath);
            byte[] privateKeyBytes = utf8StringPrik.getBytes();
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec =
                    new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKeyBytes));
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
    
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, priKey);
    
            byte[] result = cipher.doFinal(Base64.getDecoder().decode(mw));
            return new String(result);
    
        }
    
    
        public static void main(String[] args) throws Exception {
        
    //        File pubKeyFile = FileUtil.file("D:/rsa2/rsa_public.key");
            File pubKeyFile = FileUtil.file("classpath:rsa_public.key");
            String encryptStr = encrypt("20230609", pubKeyFile.getPath());
            System.err.println(encryptStr); //密文每次都不一样
    
    //        File filePrk = FileUtil.file("D:/rsa2/rsa_private.key");
            File filePrk = FileUtil.file("classpath:rsa_private.key");
            String decryptStr = decrypt(encryptStr, filePrk.getPath());
            System.err.println(decryptStr); //解出的明文都是 20230609
        }
    
    
    
    }