[distcc] LZO compression

[Martin Pool]

On 16 Dec 2002, Aaron Lehmann <aaronl at vitelus.com> wrote:
> If distcc is being tunneled over SSH, no such message digest would be
> necessary. SSH does its own strong hashing, but it's SHA-1 and
> designed to withstand cryptographic attacks. It should definately be
> adequate to guarentee the integrity of distcc communications.

Yes.

> Since distcc will hopefully support ssh as a transport natively, we
> should keep this in mind and make the digest an optional part of the
> protocol.

So the question is whether the marginal cost of doing our own digest
is so great as to make it worth varying the protocol and code path
depending on whether ssh is used or not.  I'd prefer simplicity unless
there's a measurable difference.

We might also consider whether it's worth compressing data going in to
SSH, or whether we should rely on its optional compression.

There might be some value in using an integrity check even for
tunnelled connections.  For example, I know some people use rsh (which
doesn't have a md) for speed inside clusters, and they might want to
use distcc.  There have been ssh bugs that caused streamed connections
to get corrupted, though I think not recently.

-- 
Martin