ECIES在Java中的安全模式与填充方案实践

Cipher c = Cipher.getInstance("ECIES");

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.70</version> <!-- 使用最新稳定版本 -->
</dependency>
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcpkix-jdk15on</artifactId>
    <version>1.70</version> <!-- 使用最新稳定版本 -->
</dependency>

implementation 'org.bouncycastle:bcprov-jdk15on:1.70' // 使用最新稳定版本
implementation 'org.bouncycastle:bcpkix-jdk15on:1.70' // 使用最新稳定版本

import java.security.Security;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class ECIESUtil {
    static {
        if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
            Security.addProvider(new BouncyCastleProvider());
        }
    }
    // ... 其他代码
}

Cipher c = Cipher.getInstance("ECIES/None/NoPadding", "BC");

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECParameterSpec;
import org.bouncycastle.jce.spec.ECPrivateKeySpec;
import org.bouncycastle.jce.spec.ECPublicKeySpec;
import org.bouncycastle.util.encoders.Base64;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IESParameterSpec;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;

public class ECIESExample {

    static {
        // 注册Bouncy Castle提供者
        if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
            Security.addProvider(new BouncyCastleProvider());
            System.out.println("Bouncy Castle Provider added.");
        }
    }

    /**
     * 生成EC密钥对
     * @return 密钥对
     * @throws NoSuchAlgorithmException
     * @throws InvalidAlgorithmParameterException
     */
    public static KeyPair generateECKeyPair() throws NoSuchAlgorithmException, InvalidAlgorithmParameterException {
        // 使用NIST P-256曲线 (secp256r1)
        // 也可以使用其他曲线，如 secp384r1, secp521r1
        ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp256r1");
        KeyPairGenerator g = KeyPairGenerator.getInstance("EC", BouncyCastleProvider.PROVIDER_NAME);
        g.initialize(ecSpec, new SecureRandom());
        return g.generateKeyPair();
    }

    /**
     * ECIES加密方法
     * @param msg 待加密的明文
     * @param publicKey 接收方的公钥
     * @return 加密后的字节数组
     * @throws Exception 各种加密异常
     */
    public static byte[] eccEncrypt(String msg, PublicKey publicKey) throws Exception {
        // ECIES参数：d和e是KDF的派生参数，256是MAC的密钥长度（bit）
        // 这些参数在加解密时必须保持一致
        byte[] d = new byte[]{1, 2, 3, 4, 5, 6, 7, 8}; // KDF Derivation parameters
        byte[] e = new byte[]{8, 7, 6, 5, 4, 3, 2, 1}; // KDF Encoding parameters
        IESParameterSpec param = new IESParameterSpec(d, e, 256);

        Cipher c = Cipher.getInstance("ECIES/None/NoPadding", BouncyCastleProvider.PROVIDER_NAME);
        c.init(Cipher.ENCRYPT_MODE, publicKey, param);

        byte[] message = msg.getBytes("UTF-8");
        return c.doFinal(message);
    }

    /**
     * ECIES解密方法
     * @param cipherText 待解密的密文
     * @param privateKey 接收方的私钥
     * @return 解密后的明文字符串
     * @throws Exception 各种解密异常
     */
    public static String eccDecrypt(byte[] cipherText, PrivateKey privateKey) throws Exception {
        // ECIES参数：必须与加密时使用的参数一致
        byte[] d = new byte[]{1, 2, 3, 4, 5, 6, 7, 8};
        byte[] e = new byte[]{8, 7, 6, 5, 4, 3, 2, 1};
        IESParameterSpec param = new IESParameterSpec(d, e, 256);

        Cipher c = Cipher.getInstance("ECIES/None/NoPadding", BouncyCastleProvider.PROVIDER_NAME);
        c.init(Cipher.DECRYPT_MODE, privateKey, param);

        byte[] decryptedMessage = c.doFinal(cipherText);
        return new String(decryptedMessage, "UTF-8");
    }

    public static void main(String[] args) {
        try {
            // 1. 生成密钥对
            KeyPair keyPair = generateECKeyPair();
            PublicKey publicKey = keyPair.getPublic();
            PrivateKey privateKey = keyPair.getPrivate();

            System.out.println("--- 密钥信息 ---");
            System.out.println("Public Key (Base64): " + Base64.toBase64String(publicKey.getEncoded()));
            System.out.println("Private Key (Base64): " + Base64.toBase64String(privateKey.getEncoded()));
            System.out.println("----------------\n");

            String originalMessage = "Hello, ECIES encryption with Bouncy Castle!";
            System.out.println("原始消息: " + originalMessage);

            // 2. 加密
            byte[] encryptedData = eccEncrypt(originalMessage, publicKey);
            System.out.println("加密后的数据 (Base64): " + Base64.toBase64String(encryptedData));

            // 3. 解密
            String decryptedMessage = eccDecrypt(encryptedData, privateKey);
            System.out.println("解密后的消息: " + decryptedMessage);

            // 验证
            if (originalMessage.equals(decryptedMessage)) {
                System.out.println("\nECIES 加解密成功！");
            } else {
                System.out.println("\nECIES 加解密失败！");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}