Openssl X509证书从HexStream中解析

整体思路

从hex 转换成字节流

然后从字节流中进行解析

You have access to the raw certificate in memory.

In the case that you have access to the raw encoding of the certificate in memory, you can parse it as follows. This is useful if you have stored raw certificates in a database or similar data store.

#include 
#include 
#include 

const unsigned char *data = ... ;
size_t len = ... ;

X509 *cert = d2i_X509(NULL, &data, len);
if (!cert) {
	fprintf(stderr, "unable to parse certificate in memory\n");
	return EXIT_FAILURE;
}

// any additional processing would go here..

X509_free(cert);

std::string hex_str = "30820317308201ffa003020102021432e1f.....";

// hex -> binaryData
std::vector<uint8_t> binaryData;
for (size_t i = 0; i < hex_str.size(); i += 2) {
    unsigned int byte;
    sscanf(hex_str.substr(i, 2).c_str(), "%02X", &byte);
    binaryData.push_back(byte);
}
 // 将 char* 转换为 unsigned char*
const unsigned char* uchar_ptr = binaryData.data();

size_t len = binaryData.size();
X509 *cert  = d2i_X509(NULL,&uchar_ptr,len);

if (!cert) {
    printf("Failed to load certificate from bytes\n");
    return 1;
}

// 打印证书信息
X509_print_fp(stdout, cert);

// 释放资源
X509_free(cert);

使用CryptoPP 解析

使用 CryptoPP 库进行解析

   std::string hex_str = "30820317308201ffa003020102021.....";

    std::string binaryData;
    CryptoPP::StringSource(hex_str, true,
                 new CryptoPP::HexDecoder(
                         new CryptoPP::StringSink(binaryData)
                 )
    );


    CryptoPP::ByteQueue googleq, thawteq, googletbs, thawtespki;
    CryptoPP::SecByteBlock certSignature;

    googleq.Put((const CryptoPP::byte*)binaryData.data(), binaryData.size());

    CryptoPP::X509Certificate cert;

    cert.Load(googleq);

    // 获取公钥
    const CryptoPP::PublicKey& publicKey = cert.GetSubjectPublicKey();

    // 如果你确定证书的类型是 RSA，你可以将 PublicKey 强制转换为 RSA 公钥
    const CryptoPP::RSA::PublicKey& rsaPublicKey = dynamic_cast<const RSA::PublicKey&>(publicKey);
    // 获取 RSA 模数
    const CryptoPP::Integer& modulus = rsaPublicKey.GetModulus();


// 打印公钥信息
    std::cout << "Public Key: " <<rsaPublicKey.GetPublicExponent()<< std::endl;
    // 打印 RSA 模数
    std::cout << "RSA Modulus: " << modulus<< std::endl;