ecc加密算法java

以下是使用Java实现ECC加密算法的示例代码：

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import java.security.Signature;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Hex;

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

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

        // 显示密钥对
        System.out.println("Private key: " + Hex.toHexString(privateKey.getEncoded()));
        System.out.println("Public key: " + Hex.toHexString(publicKey.getEncoded()));

        // 签名
        Signature signature = Signature.getInstance("SHA256withECDSA", "BC");
        signature.initSign(privateKey);
        byte[] message = "Hello, world!".getBytes();
        signature.update(message);
        byte[] signatureBytes = signature.sign();
        System.out.println("Signature: " + Hex.toHexString(signatureBytes));

        // 验证签名
        signature.initVerify(publicKey);
        signature.update(message);
        boolean verified = signature.verify(signatureBytes);
        System.out.println("Verified: " + verified);
    }
}

该示例代码使用Bouncy Castle库实现了ECC加密算法，包括生成密钥对、签名和验证签名等操作。其中，生成密钥对使用256位的椭圆曲线，签名算法使用SHA256withECDSA。