CRYPT_SIGN_MESSAGE_PARA signPara = { sizeof(signPara) };
signPara.dwMsgEncodingType = X509_ASN_ENCODING | PKCS_7_ASN_ENCODING;
signPara.pSigningCert = pCertContext;
signPara.HashAlgorithm.pszObjId = (LPSTR)szOID_CP_GOST_R3411_12_256;

CADES_SIGN_PARA cadesSignPara = { sizeof(cadesSignPara) };
cadesSignPara.dwCadesType = CADES_BES;

CADES_SIGN_MESSAGE_PARA para = { sizeof(para) };
para.pSignMessagePara = &signPara;
para.pCadesSignPara = &cadesSignPara;

const unsigned char *pbToBeSigned[] = { data.data() };
DWORD cbToBeSigned[] = { data.size() };
if (!CadesSignMessage(&para, TRUE, 1, pbToBeSigned, cbToBeSigned, &pSignedMessage))
    throw std::runtime_error("Ошибка вычисления подписи: " + std::to_string(GetLastError()));