Botan 是一个 C++ 的加密算法库，支持 AES, DES, SHA-1, RSA, DSA, Diffie-Hellman 等多种算法，支持 X.509 认证以及CRLs 和 PKCS #10

botan-demo.c

#include
#include
#include
using namespace Botan;

#include
#include

int main(int argc, char* argv[])
{
if(argc != 5)
{
std::cout << "Usage: " << argv[0] << " "
<< " " << std::endl;
return 1;
}

try
{
const std::string arg_passphrase = argv[1];
const std::string arg_ca_cert = argv[2];
const std::string arg_ca_key = argv[3];
const std::string arg_req_file = argv[4];

AutoSeeded_RNG rng;

X509_Certificate ca_cert(arg_ca_cert);

std::auto_ptr privkey(
PKCS8::load_key(arg_ca_key, rng, arg_passphrase)
);

X509_CA ca(ca_cert, *privkey);

// got a request
PKCS10_Request req(arg_req_file);

// you would insert checks here, and perhaps modify the request
// (this example should be extended to show how)

// now sign the request
X509_Time start_time(system_time());
X509_Time end_time(system_time() + 365 * 60 * 60 * 24);

X509_Certificate new_cert = ca.sign_request(req, rng,
start_time, end_time);

// send the new cert back to the requestor
std::cout << new_cert.PEM_encode();
}
catch(std::exception& e)
{
std::cout << e.what() << std::endl;
return 1;
}
return 0;
}