encrypting files + filestreams?

[James Stroud]

per9000 wrote:
> Also I wonder if this can be solved with filestreams (Are there
> streams in python? The only python file streams I found in the evil
> search engine was stuff in other forums.)

Check the source to: http://passerby.sf.net

In it you will find the jenncrypt module that makes a file-like wrapper 
around streams for encrypting and handles padding, etc. It is designed 
for a block cipher. This is not a trivial task, actually, but all the 
code is in there. It is not intensely well documented. It is somewhat 
well organized but this was my first full size attempt at a python 
application. Please read the notes to the "SecureRandom" module inside 
if you decide to use that module as the "name is misleading" under 
certain circumstances. It is used for the padding, although the 
randomness of the padding in a block cipher is in principle not a 
practical security issue in most cases. Other than the pad generation, 
the encryption algorithm is drop-in and I use the pycrypto 
implementation of AES.

Read at least Schneier if you want to get started with such things as 
there are many caveats to using cryptographic systems.

James

-- 
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/