P2P Backup

An ex-worker of mine asked for a file from quite a while ago. After so many computers changes, I have obviously no clue where to that file. This made me think of backup software. A little skeptical with the existing paid services:

1. well, no free, or not free and unlimited;
2. actually, more important, how can I TRUST them with my files? especially those sensitive files? Even if they claim that they encrypt your files locally in your computer before upload, how can I trust them?
   
3. What if they went out business?

Even if Google offers the so-called gDrive, #2 above still remains.

OK, here's my dream backup solution:

1. P2P based.
   
• First, people will say this is such a silly idea. If I were the receiving end, why would I backup other people's files? Well, look at this way, if you offer 10MB backup space, it will try to offer you 1000MB on the network for your backup. Why, look at how much free space we have in our computer? HardDrive is getting so cheap.
  
• If enough nodes in this network and your files is spread across enough nodes, your data can be VERY secure (safe from computer crashes).
• It's free.
  
2. Strongly encrypts files locally before sharing into this P2P network.
3. In terms of implementation, prefer to built upon existing P2P protocol. Bittorrent, maybe? Why reinvent wheel?
• This is actually interesting in that there needs to be a standard P2P protocol. This protocol definitely prefers to be: robust, decentralized, efficient...
  
4. It gotta to be open source. Otherwise, I strongly doubt anyone would install it.
5. How to recover? If password based encryption, what if the user forgot the password? If PKI based, where to store the private key file? Remember, the HDD just crashed:). Maybe store the key file in your gmail;). Need more thinking on this.
   

Of course, the risks:

1. how many people will sign up this P2P network? With MPAA/RIAA suing people randomly, people are worried about running P2P software.
   
2. This can be especially troublesome if this runs on existing P2P protocol.
3. How much space people will share?

Quick search from sf.net:

1. http://sourceforge.net/projects/peer2peerbackup/
2. http://sourceforge.net/projects/p2pbackupsmile/

OK, get back to ERBA.