On Thu, 23 Jan 2003, Matthew Toseland wrote:

> > When you say powers of two - does that mean that a 5 KB file will be 
> > rounded to 8 KB? Or be split into 4 KB and 1 KB? If it is split, at what 
> 
> Rounded.

I just realized something. If files are rounded to the size which is the 
next power of 2, doesn't that mean that in the worst case, where the file 
has size n bytes, wasted space is anything up to (n-1) bytes? And in the 
average case (n/2) bytes? Is this space actually wasted? Is the empty 
space padded with zeros or random data?

I can see that this prevents any data size analysis attack on the network 
(i.e. key sizes are not indicative of content by their size), but if the 
data is encrypted, the padding with random data would probably be more 
desireable as plain zeros would introduce some level of entropy...

How far off the mark am I here?

Regards.

Gordan


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