256 bit encryption - Document Management.

We are developing a web app for patient medical record management. In this app, the user will store all his own/family health records in our cloud storage server. Feature : Upload and Download files. Requirement is : Enable 256 bit encryption (end-to-end) to upload and download files to and from my storage server (Linux box with LAMP enabled) UI Interface : To upload, download and view document should be developed. Looking for an expert who can develop this algorithm and UI. It should be a fool proof code.