Criei um aplicativo de exemplo usando o provedor oledb (SQLOLEDB e SQL Native OLEDB provider).

Caso 1: Fornecedor = SQLOLEDB

hr = ::CoInitializeEx(NULL, COINIT_MULTITHREADED);
hr = cADOConnection.CreateInstance(__uuidof(Connection));
CString con_string = "provider=SQLOLEDB;server=MYPC;Database=MyDB";

CString SSlcon_string = "provider=SQLOLEDB;Encrypt=true;TrustServerCertificate=true;server=MYPC;Database=MyDB";
CString userName = "sa";
CString Password = "sa";
BSTR bsConnection = /*con_string*/SSlcon_string.AllocSysString();
BSTR uName = userName.AllocSysString();
BSTR uPassword = Password.AllocSysString();

hr = cADOConnection->Open(bsConnection, uName, uPassword, adConnectUnspecified);
printf("connection has been established");
VARIANT vaNoRecords;
memset(&vaNoRecords, 0, sizeof vaNoRecords);
CString sql = "SELECT * FROM salary";
BSTR query = sql.AllocSysString();
_RecordsetPtr rs;
rs = cADOConnection->Execute(query, &vaNoRecords, adCmdText);
printf("connection has been established\n");

Resultado: se o certificado estiver instalado na máquina do servidor, a conexão estará segura, independentemente da ativação da cadeia de conexão Encrypt = true e TrustServerCertificate = true.

Caso 2: Provedor = SQLNCLI10.1 (provedor oledb do cliente nativo SQL)

HRESULT hr;
hr = ::CoInitializeEx(NULL, COINIT_MULTITHREADED);
hr = cADOConnection.CreateInstance(__uuidof(Connection));
CString con_string = "provider=SQLNCLI10.1;server=MYPC;Database=MyDB";

CString SSlcon_string = "provider=SQLOLEDB;Encrypt=true;TrustServerCertificate=true;server=MYPC;Database=MyDB";
CString userName = "sa";
CString Password = "sa";
BSTR bsConnection = con_string/*SSlcon_string*/.AllocSysString();
BSTR uName = userName.AllocSysString();
BSTR uPassword = Password.AllocSysString();
hr = cADOConnection->Open(bsConnection, uName, uPassword, adConnectUnspecified);
printf("connection has been established");
VARIANT vaNoRecords;
memset(&vaNoRecords, 0, sizeof vaNoRecords);
CString sql = "SELECT suppliernumber, name1 FROM zrs_supplier";
BSTR query = sql.AllocSysString();
_RecordsetPtr rs;
rs = cADOConnection->Execute(query, &vaNoRecords, adCmdText);
printf("connection has been established\n");

Resultado: se o certificado estiver instalado na máquina do servidor, a conexão estará segura, independentemente da ativação de Encrypt = true e TrustServerCertificate = true na conexão string.i.e O resultado será o mesmo que acima.

Em ambos os casos, estou recebendo o mesmo comportamento. Estou perdendo alguma coisa aqui? Qualquer sugestão será apreciada ??Pergunta original