JAVA RSA非对称加密工具类

た入场券 2022-12-22 00:45 138阅读 0赞

RSATestUtils.java

import org.apache.tomcat.util.codec.binary.Base64;
    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    import java.nio.charset.StandardCharsets;
    import java.security.*;
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.security.spec.InvalidKeySpecException;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    import java.util.HashMap;
    import java.util.Map;
    
    /**
     * @Author: JCccc
     * @Description:
     * @Date: 2020/11/17 9:05
     */
    public class RSATestUtils {
    
        public static void main(String[] args) {
            //生成公钥和私钥
            Map<Integer,String> keyMap = genKeyPair();
            //加密字符串
            String content = "JCccc-+你/好,我是需要被*加*密*的*内*容。";
            System.out.println("加密前内容:"+content);
            System.out.println("随机生成的公钥为:" + keyMap.get(0));
            System.out.println("随机生成的私钥为:" + keyMap.get(1));
            String messageEn = encrypt(content, keyMap.get(0));
            System.out.println("加密后的内容为:" + messageEn);
            String messageDe = decrypt(messageEn, keyMap.get(1));
            System.out.println("还原后的内容为:" + messageDe);
        }
    
        //随机生成密钥对
        public static Map genKeyPair() {
            // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
            KeyPairGenerator keyPairGen = null;
    
            try {
                keyPairGen = KeyPairGenerator.getInstance("RSA");
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
    
            // 初始化密钥对生成器，密钥大小为96-1024位
            assert keyPairGen != null;
            keyPairGen.initialize(1024, new SecureRandom());
            // 生成一个密钥对，保存在keyPair中
            KeyPair keyPair = keyPairGen.generateKeyPair();
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  // 得到公钥
            String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
            // 得到私钥字符串
            String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
            // 将公钥和私钥保存到Map
            Map<Integer, String> keyMap = new HashMap<>();
            keyMap.put(0, publicKeyString);  //0表示公钥
            keyMap.put(1, privateKeyString);  //1表示私钥
            return keyMap;
        }
    
        /** RSA公钥加密
         * @param str  加密字符串
         * @param publicKey  公钥
         * @return  密文
         */
        public static String encrypt(String str, String publicKey) {
            //base64编码的公钥
            byte[] decoded = Base64.decodeBase64(publicKey);
            RSAPublicKey pubKey = null;
            String outStr = null;
    
            try {
                pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
                Cipher cipher = Cipher.getInstance("RSA");
                cipher.init(Cipher.ENCRYPT_MODE, pubKey);
                outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes(StandardCharsets.UTF_8)));
            } catch (InvalidKeySpecException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException | NoSuchPaddingException | NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
            //RSA加密
            return outStr;
        }
    
        /**  RSA私钥解密
         * @param str   加密字符串
         * @param privateKey  私钥
         * @return  铭文
         */
        public static String decrypt(String str, String privateKey) {
            //64位解码加密后的字符串
            byte[] inputByte = Base64.decodeBase64(str.getBytes(StandardCharsets.UTF_8));
            //base64编码的私钥
            byte[] decoded = Base64.decodeBase64(privateKey);
            RSAPrivateKey priKey = null;
            //RSA解密
            Cipher cipher = null;
            String outStr = null;
    
            try {
                priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
                cipher = Cipher.getInstance("RSA");
                cipher.init(Cipher.DECRYPT_MODE, priKey);
                outStr = new String(cipher.doFinal(inputByte));
            } catch (InvalidKeySpecException | NoSuchAlgorithmException | NoSuchPaddingException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException e) {
                e.printStackTrace();
            }
            return outStr;
        }
    
    
    }

测试示例：

简单应用场景： 先生成公私钥匙对， 前端拿公钥加密 ，后端拿私钥解密。

![20201117091828553.png][]

[20201117091828553.png]: /images/20221120/ecfb1d49218546d5925d876fe916e276.png