(fwd from uke@jeremy.org) thanks and patch

[Martin Pool]

> > On Tue, Mar 19, 2002 at 08:21:36AM -0800, jeremy bornstein wrote:
> > > The encryption program I'm using, gpg, includes a small bit of header
> > > information with the encrypted file, thus changing the size.  Gpg is a
> > > public key encryption program which at least includes the numeric key
> > > ID of the recipient's key.  Since folks can have many keys, this is
> > > useful information to have with each bit of data.  It might be
> > > possible to strip this information off, but then the whole process
> > > would be version-sensitive and thus error-prone, which is not what I'd
> > > like in a backup program!

It sounds like you're using asymmetric encryption.  So I suppose every
time you encrypt the file, gpg will generate a new session key, so an
identical cleartext file will generate a completely different
cyphertext file every time.

On 20 Mar 2002, jeremy bornstein <uke at jeremy.org> wrote:
> > Wouldn't encrypting the file with gpg change the timestamp as well as the
> > size, so rsync would still copy the file?
> 
> It certainly does--which is why I reset it afterwards.

Why not just re-encrypt the file only if it has changed since the last
transfer?  You could do that either by keeping the encrypted file on
the origin machine, or by using rsync to look at the modification time
on the remote machine.

(I'm not just saying this to be difficult.  We can't merge patches
unless there's some reason to believe people would actually use them,
or otherwise the code will become a complete mess.)

-- 
Martin