CSP接口PKCS#1签名代码

以下是使用CSP接口进行PKCS#1签名的示例代码：

#include <Windows.h>
#include <wincrypt.h>
#include <iostream>

#pragma comment(lib, "Crypt32.lib")

int main()
{
    HCRYPTPROV hProv = NULL;
    if (!CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
    {
        std::cerr << "Failed to acquire context: " << GetLastError() << std::endl;
        return 1;
    }

    const char* message = "Hello, world!";
    const DWORD messageSize = strlen(message);

    HCRYPTHASH hHash = NULL;
    if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash))
    {
        std::cerr << "Failed to create hash: " << GetLastError() << std::endl;
        CryptReleaseContext(hProv, 0);
        return 1;
    }

    if (!CryptHashData(hHash, reinterpret_cast<const BYTE*>(message), messageSize, 0))
    {
        std::cerr << "Failed to hash data: " << GetLastError() << std::endl;
        CryptDestroyHash(hHash);
        CryptReleaseContext(hProv, 0);
        return 1;
    }

    DWORD signatureSize = 0;
    if (!CryptSignHash(hHash, AT_SIGNATURE, NULL, 0, NULL, &signatureSize))
    {
        std::cerr << "Failed to determine signature size: " << GetLastError() << std::endl;
        CryptDestroyHash(hHash);
        CryptReleaseContext(hProv, 0);
        return 1;
    }

    std::cout << "Signature size: " << signatureSize << std::endl;

    BYTE* signature = new BYTE[signatureSize];
    if (!CryptSignHash(hHash, AT_SIGNATURE, NULL, 0, signature, &signatureSize))
    {
        std::cerr << "Failed to sign hash: " << GetLastError() << std::endl;
        delete[] signature;
        CryptDestroyHash(hHash);
        CryptReleaseContext(hProv, 0);
        return 1;
    }

    std::cout << "Signature: ";
    for (DWORD i = 0; i < signatureSize; ++i)
    {
        std::cout << std::hex << static_cast<int>(signature[i]);
    }
    std::cout << std::endl;

    delete[] signature;

    CryptDestroyHash(hHash);
    CryptReleaseContext(hProv, 0);

    return 0;
}

该代码使用 `CryptAcquireContext` 函数获取一个CSP句柄，使用 `CryptCreateHash` 函数创建一个SHA-256哈希对象，并使用 `CryptHashData` 函数将消息哈希计算。接着，使用 `CryptSignHash` 函数进行PKCS#1签名。注意，使用 `CryptSignHash` 函数签名前，需要先确定签名所需的缓冲区大小，可以通过传递一个空的缓冲区和缓冲区大小为0的参数调用该函数来确定签名所需的缓冲区大小。签名结果为字节数组，可以将其转换为十六进制字符串进行显示。最后，使用 `CryptDestroyHash` 和 `CryptReleaseContext` 函数释放资源。