ULONG DecryptMsg(PVOID pbEncryptedBlob, ULONG cbEncryptedBlob)
{
    if (HCERTSTORE hCertStore = CertOpenStore(CERT_STORE_PROV_SYSTEM, X509_ASN_ENCODING, 0, CERT_SYSTEM_STORE_LOCAL_MACHINE, L"MY"))
    {
        CRYPT_DECRYPT_MESSAGE_PARA DecryptParams = {
            sizeof(DecryptParams), X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, 1, &hCertStore
        };

        ULONG cb = cbEncryptedBlob;
        ULONG dwError;
        do
        {
            if (PVOID buf = LocalAlloc(0, cb))
            {
                dwError = CryptDecryptMessage(&DecryptParams,
                    (PBYTE)pbEncryptedBlob, cbEncryptedBlob,
                    (PBYTE)buf, &cb, 0)
                    ? NOERROR : GetLastError();

                LocalFree(buf);
            }
            else
            {
                dwError = GetLastError();
            }
        } while (dwError == ERROR_MORE_DATA);

        CertCloseStore(hCertStore, 0);

        return dwError;
    }

    return GetLastError();
}

void CryptMsg(PVOID pbPlain, ULONG cbPlain)
{
    if (HCERTSTORE hCertStore = CertOpenStore(CERT_STORE_PROV_SYSTEM, X509_ASN_ENCODING, 0, CERT_SYSTEM_STORE_LOCAL_MACHINE, L"MY"))
    {
        if (PCCERT_CONTEXT pCertContext = GetCert(hCertStore))
        {
            CRYPT_ENCRYPT_MESSAGE_PARA EncryptParams = {
                sizeof(EncryptParams), PKCS_7_ASN_ENCODING | X509_ASN_ENCODING, 0, { szOID_NIST_AES256_CBC }
            };

            ULONG cbEncryptedBlob = cbPlain + pCertContext->cbCertEncoded;
            ULONG dwError;

            do
            {
                if (PVOID pbEncryptedBlob = LocalAlloc(0, cbEncryptedBlob))
                {
                    dwError = CryptEncryptMessage(
                        &EncryptParams,
                        1, &pCertContext,
                        (PBYTE)pbPlain, cbPlain,
                        (PBYTE)pbEncryptedBlob, &cbEncryptedBlob)
                        ? NOERROR : GetLastError();

                    if (dwError == NOERROR)
                    {
                        /****  write (pbEncryptedBlob, cbEncryptedBlob) to file  ****/;
                        DecryptMsg(pbEncryptedBlob, cbEncryptedBlob);
                    }

                    LocalFree(pbEncryptedBlob);
                }
                else
                {
                    dwError = GetLastError();
                }

            } while (dwError == ERROR_MORE_DATA);

            CertFreeCertificateContext(pCertContext);
        }
        CertCloseStore(hCertStore, 0);
    }
}