I want to host confidential data on Sharepoint 2013 and would like to encrypt these data on a file level.
There is already a Transparent Data Encryption (TDE) feature available for Sharepoint but it is encryption at the database level.
If an attacker (somehow) bypasses the permissions set on the SharePoint library, then ideally this file should appear encrypted and not made available to the attacker.
Decrypting the file could require the correct Windows identity or a admin-defined password.
The million dollar question is: how can this be achieved? Can I write a custom web part and attach it to the library and encrypt all files that are uploaded with a password?