Encrypt database string VB.NET

Encrypt your connection string and then use it in your app.confing.
For encryption check this link:[^]

If you want to protect your connection string it would be better not to store it in the .config file.
If you keep the connection string in code and use an obfuscator like Dotfuscator, it will be protected better.
Even better is to use encryption, see: Encrypting and Decrypting Strings in Visual Basic | Microsoft Docs[.]
Also see: .NET Encryption Simplified[^]

You can use an algorithm to encrypt the connectionstring and use an encryption key to encrypt it. You can store it in your config file after it is encrypted and when needed for any database operation, you can decrypt it using same encryption key and use it. The key used to encrypt can be defined as constant in your code.

E.g.:
This article

I have done this a few times. Its a pain to figure out the first time. Basically, there is a .net command line tool that you can use to encrypt sections of a web.config file.

Now, you have to encrypt the file on the pc/server it will reside on. This is because the encryption is done using keys specific to that machine. This makes it a pain because the web.config file will be different on your local pc and on the server.

Because of this I recommend first moving the connection strings into a separate config file. This way you can move that file to the server when ready and encrypt that file only. You can continue to make changes to the web.config file and deploy with out undoing your encryption.

It will look something like this in the web.config file to point to a separate file for connection string.
<connectionStrings configSource="ConnectionStrings.config">


Article to move connection strings to a separate file:
ASP.NET MVC: Keep Private Settings Out of Source Control | John Atten[^]

To encrypt web.config file
How to: Encrypt a web.config File[^]


Good luck!