Java BC包解析DER的SM2签名值转换成16进制字符串

以下是Java代码示例，用于解析DER编码的SM2签名值，并将其转换为十六进制字符串：

import java.io.IOException;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.ECGenParameterSpec;
import java.security.spec.ECParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;

import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.sec.SECNamedCurves;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.crypto.digests.SM3Digest;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.signers.SM2Signer;
import org.bouncycastle.crypto.util.PrivateKeyFactory;
import org.bouncycastle.crypto.util.PublicKeyFactory;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Hex;

public class SM2Utils {

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    public static byte[] sign(byte[] message, byte[] privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException, IOException {
        // 使用SM3摘要算法计算消息的哈希值
        byte[] digest = new byte[32];
        SM3Digest sm3 = new SM3Digest();
        sm3.update(message, 0, message.length);
        sm3.doFinal(digest, 0);

        // 解析私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);
        KeyFactory keyFactory = KeyFactory.getInstance("EC", "BC");
        ECPrivateKeyParameters privateKeyParams = (ECPrivateKeyParameters) PrivateKeyFactory.createKey(pkcs8KeySpec);

        // 创建SM2签名器
        SM2Signer signer = new SM2Signer();
        ECDomainParameters ecParams = privateKeyParams.getParameters();
        ECParameterSpec ecSpec = new ECParameterSpec(ecParams.getCurve(), ecParams.getG(), ecParams.getN(), ecParams.getH(), ecParams.getSeed());
        signer.init(true, privateKeyParams);

        // 计算签名
        signer.update(digest, 0, digest.length);
        byte[] signature = signer.generateSignature();

        // 将签名值编码为DER格式
        ASN1Integer r = new ASN1Integer(new BigInteger(1, Arrays.copyOfRange(signature, 0, 32)));
        ASN1Integer s = new ASN1Integer(new BigInteger(1, Arrays.copyOfRange(signature, 32, 64)));
        ASN1Sequence seq = new DERSequence(new ASN1Integer[] { r, s });
        byte[] derSignature = seq.getEncoded();
        return derSignature;
    }

    public static boolean verify(byte[] message, byte[] publicKey, byte[] signature) throws NoSuchAlgorithmException, InvalidKeySpecException, IOException {
        // 使用SM3摘要算法计算消息的哈希值
        byte[] digest = new byte[32];
        SM3Digest sm3 = new SM3Digest();
        sm3.update(message, 0, message.length);
        sm3.doFinal(digest, 0);

        // 解析公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(publicKey);
        KeyFactory keyFactory = KeyFactory.getInstance("EC", "BC");
        ECPublicKeyParameters publicKeyParams = (ECPublicKeyParameters) PublicKeyFactory.createKey(x509KeySpec);

        // 创建SM2签名器
        SM2Signer verifier = new SM2Signer();
        ECDomainParameters ecParams = publicKeyParams.getParameters();
        ECParameterSpec ecSpec = new ECParameterSpec(ecParams.getCurve(), ecParams.getG(), ecParams.getN(), ecParams.getH(), ecParams.getSeed());
        verifier.init(false, publicKeyParams);

        // 解码DER格式的签名值
        ASN1Sequence seq = ASN1Sequence.getInstance(signature);
        BigInteger r = ((ASN1Integer) seq.getObjectAt(0)).getValue();
        BigInteger s = ((ASN1Integer) seq.getObjectAt(1)).getValue();
        byte[] rs = new byte[64];
        System.arraycopy(r.toByteArray(), r.toByteArray().length > 32 ? 1 : 0, rs, 0, 32);
        System.arraycopy(s.toByteArray(), s.toByteArray().length > 32 ? 1 : 0, rs, 32, 32);

        // 验证签名
        verifier.update(digest, 0, digest.length);
        return verifier.verifySignature(rs);
    }

    public static void main(String[] args) throws Exception {
        // 生成密钥对
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC", "BC");
        ECGenParameterSpec ecGenSpec = new ECGenParameterSpec("sm2p256v1");
        keyPairGenerator.initialize(ecGenSpec, new SecureRandom());
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        byte[] privateKey = keyPair.getPrivate().getEncoded();
        byte[] publicKey = keyPair.getPublic().getEncoded();

        // 签名
        byte[] message = "Hello, SM2!".getBytes();
        byte[] signature = sign(message, privateKey);

        // 输出签名值的十六进制字符串
        String signatureHex = Hex.toHexString(signature);
        System.out.println(signatureHex);

        // 验证签名
        boolean verified = verify(message, publicKey, signature);
        System.out.println("Signature verified: " + verified);
    }
}
``