I recently purchased a n810 to store my personal data and to stay online when away from my computer. While I love the device for its simplicity and privacy (no cell phone contracts, etc), I find it terribly lacking in applications that keep data secure. Therefore I would like to start developing an application to address these inadequacies as soon as possible.

The concept is a simple one, but as I am new to the Maemo scene I would like a bit of guidance or information before digging around in the very large code base.

My idea is to present 3 levels of security for the MyData folder on the Nokia. At the first level, and probably for release 1, a simply password will be required for any and all accesses into this folder by any program. This folder will be kept encrypted by a secure algorithm that will cause a minimal hit to file system performance and speed. To maintain absolute security and the best compatibility with existing programs this change must be transparent to the other applications. At later releases I would like to use the camera to take retina scans and use the mic for voice comparisons (see http://www.biowallet.net/).

In theory I expect that I will have to write a hook for any access into this folder and interrupt the process to present a request for identification, once completed it will decrypt the folder and allow the access. One thing I need to know right off the bat is if this folder is required by certain systems in Maemo for purposes other than storage. Obviously I do not want the program to continually request identification each time Maemo checks a user setting or something.
In its most basic form, all data in MyData will reside as a single block of encrypted data that is only decrypted when proper identification is provided. As far as Maemo is concerned, this folder should remain unchanged and intact, so my program should act as a transparent proxy to reinterpret the os request for data.

While the task itself is fairly straight forward, I would like more information and guidance on the implementation of the file system lock for MyData. I am no stranger to the linux environment, however I am be no means an expert. Therefore I would first like to know where I would need to look in the Maemo distribution to implement such a lock, and then I would like to any information about the best way to implement such a system in linux.

I am currently reading up on maemo and hildon development, as well as studying the implementation of the linux file system operation in maemo. This research can be greatly sped up by help from people who have used this software before and know much more than I do.

I need to have at least a basic version of this system working by the end of January so any information that might lead to a workable solution will be greatly appreciated.

A little background on me; I am not afraid of editing binary files, as I fear that some of the implementation might reside in Nokia's closed source applications. Also I an quite fluent in both C and C++ but new to the ARM architecture and these devices in general. I have a basic understanding of linux and the systems that work underneath maemo, but in this phase of program design any information is welcome.

Thank you for your time
Red Comet