procedure Sign(hCertContext:PCCERT_CONTEXT; buf:pointer; buf_len:dword; var result:pointer);
Var sigParams:CRYPT_SIGN_MESSAGE_PARA;
    res_len:dword;
begin
  ZeroMemory(@sigParams, sizeof(CRYPT_SIGN_MESSAGE_PARA));
  sigParams.cbSize:=SizeOf(CRYPT_SIGN_MESSAGE_PARA);
  sigParams.dwMsgEncodingType:=X509_ASN_ENCODING or PKCS_7_ASN_ENCODING;
  sigParams.pSigningCert:=hCertContext;
  sigParams.HashAlgorithm.pszObjID:='1.2.643.7.1.1.2.2';
  sigParams.HashEncryptionAlgorithm.pszObjId:='1.2.643.7.1.1.1.1';
  sigParams.cMsgCert:=1;
  sigParams.rgpMsgCert:=@hCertContext;
//  buf_len:=0;
  if(CryptSignMessage(@sigParams, true, 1, buf, @buf_len, nil, res_len))then
  begin
    GetMem(result, res_len);
    if(CryptSignMessage(@sigParams, true, 1, buf, @buf_len, result, res_len))then
    begin
    end;
  end;
end;