How to best update remote compressed, encrypted archives incrementally?

[Steven D'Aprano]

On Fri, 10 Mar 2006 15:13:07 +0100, robert wrote:

> Hello,
> 
> I want to put (incrementally) changed/new files from a big file tree 
> "directly,compressed and password-only-encrypted" to a remote backup 
> server incrementally via FTP,SFTP or DAV....  At best within a closed 
> algorithm inside Python without extra shell tools.

What do you mean by "closed algorithm"?

The only thing I can think of is you mean a secret algorithm, one which
nobody but yourself will know. So let's get this straight... you are
asking a public newsgroup dedicated to an open-source language for
somebody to tell you a secret algorithm that only you will know?

Please tell me I've misunderstood.


> (The method should work with any protocol which allows somehow read, 
> write & seek to a remote file.)
> On the server and the transmission line there should never be 
> unencrypted data.

Break the job into multiple pieces. Your task is:

- transmit information to the remote server;

Can you use SSH for that? SSH will use industrial strength encryption,
likely better than anything you can create.

- you want to update the files at the other end;

Sounds like a job for any number of already existing technologies, like
rsync (which, by the way, already uses ssh for the encrypted transmission
of data).



-- 
Steven.