RSA公钥加密私钥解密实例

刺骨的言语ヽ痛彻心扉 2022-05-27 10:09 293阅读 0赞

1、加密、解密流程  
![这里写图片描述][70]

2、实现  
（1）RSA加密工具类 RSACrypt.java

package club.easyshare.framework.utils;
    
    import java.security.InvalidKeyException;
    import java.security.KeyFactory;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.NoSuchAlgorithmException;
    import java.security.SecureRandom;
    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;
    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    
    public class RSACrypt { 
    
        /** * 生成RAS公钥与私钥字符串，直接返回 * * @return */
        public static HashMap<String, String> getKeys() {
            HashMap<String, String> map = new HashMap<String, String>();
            KeyPairGenerator keyPairGen = null;
            try {
                keyPairGen = KeyPairGenerator.getInstance("RSA");
            } catch (NoSuchAlgorithmException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            // 初始化密钥对生成器，密钥大小为96-1024位
            keyPairGen.initialize(1024, new SecureRandom());
            // 生成一个密钥对，保存在keyPair中
            KeyPair keyPair = keyPairGen.generateKeyPair();
            // 得到公钥字符串
            String publicKey = base64ToStr(keyPair.getPublic().getEncoded());
            // 得到私钥字符串
            String privateKey = base64ToStr(keyPair.getPrivate().getEncoded());
            map.put("publicKey", publicKey);
            map.put("privateKey", privateKey);
            return map;
        }
    
        /** * 根据公钥字符串加载公钥 * * @param publicKeyStr 公钥字符串 * @return * @throws Exception */
        public static RSAPublicKey loadPublicKey(String publicKeyStr) throws Exception {
            try {
                byte[] buffer = javax.xml.bind.DatatypeConverter.parseBase64Binary(publicKeyStr);
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
                return (RSAPublicKey) keyFactory.generatePublic(keySpec);
            } catch (NoSuchAlgorithmException e) {
                throw new Exception("无此算法", e);
            } catch (InvalidKeySpecException e) {
                throw new Exception("公钥非法", e);
            } catch (NullPointerException e) {
                throw new Exception("公钥数据为空", e);
            }
        }
    
        /** * 根据私钥字符串加载私钥 * * @param privateKeyStr 私钥字符串 * @return * @throws Exception */
        public static RSAPrivateKey loadPrivateKey(String privateKeyStr) throws Exception {
            try {
                byte[] buffer = javax.xml.bind.DatatypeConverter.parseBase64Binary(privateKeyStr);
                PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");
                return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
            } catch (NoSuchAlgorithmException e) {
                throw new Exception("无此算法", e);
            } catch (InvalidKeySpecException e) {
                throw new Exception("私钥非法", e);
            } catch (NullPointerException e) {
                throw new Exception("私钥数据为空", e);
            }
        }
    
        /** * 公钥加密 * * @param publicKey 公钥 * @param plainTextData 明文数据 * @return * @throws Exception 加密过程中的异常信息 */
        public static String encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception {
            if (publicKey == null) {
                throw new Exception("加密公钥为空, 请设置");
            }
            Cipher cipher = null;
            try {
                // 使用默认RSA
                cipher = Cipher.getInstance("RSA");
                cipher.init(Cipher.ENCRYPT_MODE, publicKey);
                byte[] output = cipher.doFinal(plainTextData);
                return base64ToStr(output);
            } catch (NoSuchAlgorithmException e) {
                throw new Exception("无此加密算法");
            } catch (NoSuchPaddingException e) {
                e.printStackTrace();
                return null;
            } catch (InvalidKeyException e) {
                throw new Exception("加密公钥非法,请检查");
            } catch (IllegalBlockSizeException e) {
                throw new Exception("明文长度非法");
            } catch (BadPaddingException e) {
                throw new Exception("明文数据已损坏");
            }
        }
    
    
        /** * 私钥解密 * * @param privateKey 私钥 * @param cipherData 密文数据 * @return 明文 * @throws Exception 解密过程中的异常信息 */
        public static String decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception {
            if (privateKey == null) {
                throw new Exception("解密私钥为空, 请设置");
            }
            Cipher cipher = null;
            try {
                // 使用默认RSA
                cipher = Cipher.getInstance("RSA");
                cipher.init(Cipher.DECRYPT_MODE, privateKey);
                byte[] output = cipher.doFinal(cipherData);
                return new String(output);
            } catch (NoSuchAlgorithmException e) {
                throw new Exception("无此解密算法");
            } catch (NoSuchPaddingException e) {
                e.printStackTrace();
                return null;
            } catch (InvalidKeyException e) {
                throw new Exception("解密私钥非法,请检查");
            } catch (IllegalBlockSizeException e) {
                e.printStackTrace();
                throw new Exception("密文长度非法");
            } catch (BadPaddingException e) {
                e.printStackTrace();
                throw new Exception("密文数据已损坏");
            }
        }
    
        public static String base64ToStr(byte[] b) {
            return javax.xml.bind.DatatypeConverter.printBase64Binary(b);
        }
    
        public static byte[] strToBase64(String str) {
            return javax.xml.bind.DatatypeConverter.parseBase64Binary(str);
        }
    }

（2）生成秘钥对，加密数据、解密数据

public static void main(String[] args) throws Exception {
        //初始化阶段，初始化后生成秘钥对
        //公钥发送给消息发送方用于加密传输数据；私钥严格保存于消息接收方，收到加密的消息之后进行解密
        HashMap<String, String> map = RSACrypt.getKeys();
        String privateKeyStr=map.get("privateKey");
        String publicKeyStr=map.get("publicKey");
        System.out.println("初始化私钥为："+privateKeyStr);
        System.out.println("初始化共钥为："+publicKeyStr);
    
        //消息发送方
        String originData="周末约你看电影吧";
        System.out.println("信息原文："+originData);
        String encryptData=RSACrypt.encrypt(RSACrypt.loadPublicKey(publicKeyStr),originData.getBytes());
        System.out.println("加密后："+encryptData);
    
        //消息接收方
        String decryptData=RSACrypt.decrypt(RSACrypt.loadPrivateKey(privateKeyStr),RSACrypt.strToBase64(encryptData));
        System.out.println("解密后："+decryptData);
    }

结果输出

初始化私钥为：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 初始化共钥为：MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCNkskbzMWU65UceqB2r/JQhAh1+cGf6T5ALJdUSIfzTH1ecIzft5BmaxujRLyPsQrsMBRp/BsFA4Kguh8OZwNeXIbkaa2RQ2l2vYRawuq+o7UOjDzrKnWgyUn6SSGOuH2aqFSynYm1e/N5ny9e+Z/SJGg7sN5rLpicgzrIKZSCfwIDAQAB 信息原文：周末约你看电影吧 加密后：XeIAoNZlyn+Mk17wsdPpl8SDlaq0B8NbIvQFVg9Ja+YHxuKretNMu61IRY5EFyPL/dXC/6KiDDINglP2HRX4JNbRZgzZd1rkqExW219psHQOhFzbFYZ3yKuI72C7S4/sqIM1eqlnkvIGBhJNLwOfzF6VjplsbHAiQ4fDhA57XI8= 解密后：周末约你看电影吧

[70]: /images/20220527/5456f63856534c94b397230da4101fc9.png