如何使用Bouncy Castle ElGamal和javax.crypto.Cipher显式加密(c1、c2)元组

// 导入Bouncy Castle库
import org.bouncycastle.jce.provider.BouncyCastleProvider;

// 导入相应的包
import javax.crypto.Cipher;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;

public class ElGamalEncryptionExample {
    public static void main(String[] args) throws Exception {
        // 添加Bouncy Castle作为Provider
        Security.addProvider(new BouncyCastleProvider());
        
        // 生成ElGamal密钥对
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("ElGamal", "BC");
        keyGen.initialize(256); // 设置密钥长度
        KeyPair keyPair = keyGen.generateKeyPair();
        
        // 初始化Cipher对象
        Cipher cipher = Cipher.getInstance("ElGamal/None/NoPadding", "BC");
        cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());
        
        // 待加密的数据
        byte[] input = "Hello, Bouncy Castle!".getBytes("UTF-8");
        
        // 执行加密操作
        byte[] cipherText = cipher.doFinal(input);
        
        // 获取加密结果(c1、c2)
        byte[] c1 = new byte[cipher.getBlockSize()];
        byte[] c2 = new byte[cipher.getBlockSize()];
        
        System.arraycopy(cipherText, 0, c1, 0, c1.length);
        System.arraycopy(cipherText, c1.length, c2, 0, c2.length);
        
        // 打印加密结果
        System.out.println("c1: " + bytesToHex(c1));
        System.out.println("c2: " + bytesToHex(c2));
    }
    
    // 辅助函数：将字节数组转换为十六进制字符串
    private static String bytesToHex(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            sb.append(String.format("%02x", b));
        }
        return sb.toString();
    }
}