gmssl java 生成签名值

下面是使用 gmssl-java 库生成签名值的示例代码：

import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SM3Digest;
import org.bouncycastle.crypto.generators.ECKeyPairGenerator;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECKeyGenerationParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.signers.SM2Signer;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Hex;

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;

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

        // 生成 SM2 密钥对
        ECDomainParameters ecParams = ECNamedCurveTable.getByName("sm2p256v1");
        ECKeyGenerationParameters keyGenParams = new ECKeyGenerationParameters(ecParams, new SecureRandom());
        ECKeyPairGenerator keyPairGenerator = new ECKeyPairGenerator();
        keyPairGenerator.init(keyGenParams);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        // 待签名数据
        byte[] msg = "hello world".getBytes("UTF-8");

        // 计算消息摘要
        Digest digest = new SM3Digest();
        byte[] msgDigest = new byte[digest.getDigestSize()];
        digest.update(msg, 0, msg.length);
        digest.doFinal(msgDigest, 0);

        // 使用私钥进行签名
        SM2Signer signer = new SM2Signer();
        signer.init(true, new ECPrivateKeyParameters(((ECPrivateKey) keyPair.getPrivate()).getS(), ecParams));
        signer.update(msgDigest, 0, msgDigest.length);
        byte[] signature = signer.generateSignature();

        System.out.println("私钥：" + Hex.toHexString(((ECPrivateKey) keyPair.getPrivate()).getS().toByteArray()));
        System.out.println("公钥：" + Hex.toHexString(((ECPublicKey) keyPair.getPublic()).getQ().getEncoded(false)));
        System.out.println("待签名数据：" + Hex.toHexString(msg));
        System.out.println("签名值：" + Hex.toHexString(signature));
    }
}

在上述代码中，我们使用 `SM2Signer` 类实现了 SM2 签名，并使用 `SM3Digest` 实现了消息摘要计算。执行代码后，会输出生成的私钥、公钥、待签名数据和签名值。