java rsa 加解密实现

RSA算法是一种非对称加密算法，可以实现加密和解密操作。以下是Java中使用RSA算法进行加解密的示例代码：

1. 生成密钥对

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;

public class RSAUtil {
    
    public static KeyPair generateKeyPair() throws NoSuchAlgorithmException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048);
        return keyPairGenerator.generateKeyPair();
    }
    
}

2. 加密数据

import java.security.Key;
import java.security.KeyFactory;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
import javax.crypto.Cipher;

public class RSAUtil {
    
    // 省略 generateKeyPair 方法
    
    public static String encrypt(String data, String publicKey) throws Exception {
        byte[] keyBytes = Base64.getDecoder().decode(publicKey);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        Key key = keyFactory.generatePublic(new PKCS8EncodedKeySpec(keyBytes));
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] dataBytes = data.getBytes();
        byte[] encryptedDataBytes = cipher.doFinal(dataBytes);
        return Base64.getEncoder().encodeToString(encryptedDataBytes);
    }
    
}

3. 解密数据

import java.security.Key;
import java.security.KeyFactory;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
import javax.crypto.Cipher;

public class RSAUtil {
    
    // 省略 generateKeyPair 方法和 encrypt 方法
    
    public static String decrypt(String encryptedData, String privateKey) throws Exception {
        byte[] keyBytes = Base64.getDecoder().decode(privateKey);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        Key key = keyFactory.generatePrivate(new PKCS8EncodedKeySpec(keyBytes));
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] encryptedDataBytes = Base64.getDecoder().decode(encryptedData);
        byte[] dataBytes = cipher.doFinal(encryptedDataBytes);
        return new String(dataBytes);
    }
    
}

示例代码中使用了Java自带的Base64类进行数据编码和解码，可以自行替换为其他编码方式。