Network Programming in .NET

If your database server is on a different machine to your webserver, and the SQL queries travel through the network, then they are liable to be sniffed by third parties sharing the same network.

However, if you add the words:

Encrypt=True; TrustServerCertificate=True

To your connection string then the TDS data sent from client to server will be encrypted, and impossible to sniff from the network.

You can verify the connection is secure by running the following query;

SELECT session_id, net_transport, client_net_address, local_net_address,
local_tcp_port, auth_scheme, encrypt_option
FROM sys.dm_exec_connections

According to performance tests, I found no difference between the performance of secure vs plain text secure. over a batch of 200 queries.