java实现ecdh算法代码

以下是Java实现ECDH算法的示例代码：

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import javax.crypto.KeyAgreement;
import javax.crypto.SecretKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class ECDHExample {
    public static void main(String[] args) throws Exception {
        Security.addProvider(new BouncyCastleProvider());

        // 生成ECC密钥对
        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("ECDH", "BC");
        keyGen.initialize(256);
        KeyPair keyPair = keyGen.generateKeyPair();
        PrivateKey privateKey = keyPair.getPrivate();
        PublicKey publicKey = keyPair.getPublic();

        // ECDH密钥协商
        KeyAgreement keyAgreement = KeyAgreement.getInstance("ECDH", "BC");
        keyAgreement.init(privateKey);
        keyAgreement.doPhase(publicKey, true);
        SecretKey secretKey = keyAgreement.generateSecret("AES");

        // 输出密钥
        byte[] keyBytes = secretKey.getEncoded();
        System.out.println("ECDH Secret Key: " + bytesToHexString(keyBytes));
    }

    private static String bytesToHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            sb.append(String.format("%02X", b));
        }
        return sb.toString();
    }
}

该示例使用Bouncy Castle作为ECC加密提供程序，并使用256位曲线生成密钥对。在ECDH密钥协商期间，使用私钥和公钥执行doPhase()方法。最后，使用AES算法生成共享密钥，并将其输出为十六进制字符串。