sm2椭圆曲线公钥java

以下是使用Bouncy Castle库生成SM2椭圆曲线公钥的Java代码示例：

import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
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.jce.provider.BouncyCastleProvider;
import org.bouncycastle.math.ec.ECPoint;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.interfaces.ECPublicKey;

public class SM2PublicKeyGenerator {
    public static void main(String[] args) throws Exception {
        Security.addProvider(new BouncyCastleProvider());

        // 定义SM2椭圆曲线参数
        BigInteger p = new BigInteger("FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFF", 16);
        BigInteger a = new BigInteger("FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFC", 16);
        BigInteger b = new BigInteger("28E9FA9E9D9F5E344D5A9E4BCF6509A7F39789F515AB8F92DDBCBD414D940E93", 16);
        BigInteger n = new BigInteger("FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFF7203DF6B21C6052B53BBF40939D54123", 16);
        BigInteger gx = new BigInteger("32C4AE2C1F1981195F9904466A39C9948FE30BBFF2660BE171F996FF2C723AC4", 16);
        BigInteger gy = new BigInteger("BC3736A2F4F6779C59BDCEE36B692153D0A9877CC62A474002DF32E52139F0A0", 16);
        ECDomainParameters domainParams = new ECDomainParameters(p, a, b, new ECDomainParameters.Fp(gx, gy), n);

        // 生成SM2公私钥对
        ECKeyPairGenerator keyPairGenerator = new ECKeyPairGenerator();
        ECKeyGenerationParameters keyGenParams = new ECKeyGenerationParameters(domainParams, null);
        keyPairGenerator.init(keyGenParams);
        AsymmetricCipherKeyPair keyPair = keyPairGenerator.generateKeyPair();
        ECPrivateKeyParameters privateKey = (ECPrivateKeyParameters) keyPair.getPrivate();
        ECPublicKeyParameters publicKey = (ECPublicKeyParameters) keyPair.getPublic();

        // 将SM2公钥转换为Java标准的公钥对象
        ECPoint q = publicKey.getQ();
        ECPublicKey javaPublicKey = (ECPublicKey) KeyPairGenerator.getInstance("EC", "BC").generatePublic(new java.security.spec.ECPublicKeySpec(q, domainParams.toECParameterSpec()));

        // 输出SM2公钥的十六进制表示
        byte[] encoded = javaPublicKey.getEncoded();
        String hexString = bytesToHexString(encoded);
        System.out.println(hexString);
    }

    private static String bytesToHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            String hex = Integer.toHexString(b & 0xFF);
            if (hex.length() == 1) {
                sb.append('0');
            }
            sb.append(hex);
        }
        return sb.toString();
    }
}

注意：以上代码中的SM2椭圆曲线参数仅供参考，实际应用中需要使用正确的参数。同时，为了保证生成的SM2公钥能够与其他系统兼容，需要根据具体需求进行编码和格式化。