How to secure connection between Vb6 application and mssql server? - sql-server

Question

I am working on a legacy application which uses sqloledb provider and activex data objects to connect to mssql database. Now I need to encrypt the connection between the application and server without force encryption option in sql server.
I have installed a self signed certificate in the sql server instance and tried putting the Encrypt=true and Trustservercertificate=true in connection string. But the connection is not encrypted.
I have tried using ODBC provider with ADO and while using encrypt=true and trustservercertificate=true, I am getting a SSL security error which opening the connection.
Please let me know how to establish a secure connection using ADO 2.8 library.
Private Sub Command1_Click()
Dim sConnectionString As String
Dim strSQLStmt As String
'-- Build the connection string
'sConnectionString = "UID=userid;PWD=password;Initial Catalog=EHSC_SYM_Kings_Development;Server=EHILP-257\MIB14;Provider=MSOLEDBSQL;Encrypt=YES;trustServerCertificate=YES"
'sConnectionString = "Provider=sqloledb;Data Source=192.168.27.91\MIB14;Initial Catalog=EHSC_SYM_Kings_Development;User Id=userid;Password=password;Encrypt=YES;trustServerCertificate=YES"
'sConnectionString = "driver={SQL Server};server=192.168.27.91\MIB14;user id=userid;password=password;Initial Catalog=EHSC_SYM_Kings_Development;Encrypt=Yes;trustServerCertificate=True"
sConnectionString = "Provider=SQLNCLI11;Server=192.168.27.91\MIB14;Database=EHSC_SYM_Kings_Development;Uid=userid;Pwd=password;Encrypt=yes;trustServerCertificate=True"
strSQLStmt = "select * from dbo.patient where pat_pid = '1001'"
'DB WORK
Dim db As New ADODB.Connection
Dim cmd As New ADODB.Command
Dim rs As New ADODB.Recordset
Dim result As String
db.ConnectionString = sConnectionString
db.Open 'open connection
With cmd
.ActiveConnection = db
.CommandText = strSQLStmt
.CommandType = adCmdText
End With
With rs
.CursorType = adOpenStatic
.CursorLocation = adUseClient
.LockType = adLockOptimistic
.Open cmd
End With
If rs.EOF = False Then
rs.MoveFirst
Let result = rs.Fields(0)
End If
'close conns
rs.Close
db.Close
Set db = Nothing
Set cmd = Nothing
Set rs = Nothing
End Sub

Answer 1

Thank you all for your suggestions, I finally managed to make the connection secure by changing the driver to sqlserver native client 11(ODBC). Looks like sqloledb doesn't have support for tls. Changing the driver to ODBC doesn't seem to change the behaviour much. Rest of my code works fine without any changes
sConnectionString = "Driver={SQL Server Native Client 11.0};Server=192.168.27.91\MIB14;Database=xxxxxxxx;user id=xxxxxxx;password=xxxxxxxxx;Encrypt=yes;TrustServerCertificate=yes"

Answer 2

Just went through this myself.
For your original connection string the keyword you're looking for is not "Encrypt=true" or "Encrypt=yes" like most of the internet would lead you to believe. It's "Use Encryption for Data=true".
So your connection string becomes:
sConnectionString = "Provider=SQLNCLI11;Server=192.168.27.91\MIB14;Database=EHSC_SYM_Kings_Development;Uid=userid;Pwd=password;Use Encryption for Data=true;trustServerCertificate=True"
The trustservercertificate=true is just for testing with self-signed certs... and exposing yourself to man-in-the-middle attacks ;)
For reference this was tested with:
VB6 connecting to SQL Server 2016 using SQLNCLI11 provider via ADODB.