Need app similar to BoxCryptor

We need a desktop app for Windows similar to BoxCryptor. We are looking for great design and nice structured source code, well commented, and well documented. This project is for a trusted client. No payments or milestones will be created until the project is completed, delivered and tested by the client, and the source code inspected, and until the client is satisfied with everything. However, the payment is guaranteed, and you can check my employer profile too. I have been working with the client for several months and he always pays. Whoever bids $1000 or less will be hired immediately.