Hi, and thanks for your interest in OpenAFS

On 23 Mar 2010, at 16:48, Sanket Agarwal wrote:
>       • Where can I learn about the present encryption methodology used in 
> OpenAFS for packet encryption and which module shall have the relevant code 
> section ? This can give me an insight about what can be a good way to do 
> Server side encryption!

We'd be doing this separately from OpenAFS's current (and future) wire 
encryption protocols. As I'd envisaged the project, it's not really a server 
side encryption scheme - all of the encryption and decryption work would be 
performed by the client. The purpose is to prevent the server from knowing any 
of the content uploaded by the client.

The workflow would be as follows:

*) User writes a file locally
*) Client generates a key for the file, and encrypts file with it
*) Client encrypts key with user's key, and stores encrypted key in file's 
metadata [0]
*) Client stores file on file server

Reading would work in reverse of this operation - as you can see, all of the 
cryptography is done at the client (in the cache manager). The server is 
unmodified - it just saves blobs of data.

[0] AFS doesn't currently have proper extended attributes support, so for the 
purposes of this project we'd fake metadata, by creating an additional file for 
each encrypted file, containing the set of keys. The intention would be that at 
some later date this would be folded into extended attributes.

>       • Also, a design needs to be worked out in order to allow selective 
> data sharing through management of user/data keys. I will go through the 
> documentation of OpenAFS to suggest a solution, but pointers/help is greatly 
> appreciated.

This is a much later part of the project. My suspicion is that just 
implementing single user support will likely take up most of the summer. If the 
user's key is a public key pair, then we can simply do this by
just encrypting the file key with keys for every user that should be able to 
read it. Managing these public keys beyond this is out of scope for this 
project.

>       • Who'll be likely mentoring this project, it'll be helpful if I can 
> address the demands of the mentor as he would know the requirements best!

We haven't quite sorted out mentoring assignment, but I suggested this project 
originally. There are many people on this list who will be happy to help too!

Cheers,

Simon._______________________________________________
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