Signing revisions in place

[Jens Alfke]

On 3 Oct '07, at 1:49 PM, Dustin Sallings wrote:

> It's unclear how you'd sign your own changeset in your changeset,  
> though.  In the case of gnu arch, the signature was a separate file  
> from the patch tarball itself.  If it's possible to do something  
> similar in mercurial, then it'd make sense.

That's what I tried to describe in the email that started this thread...

In a nutshell: When creating the revlog entry for a revision (the  
manifest hash + metadata + checkin comment), generate a signature of  
the entry and then append the signature to the entry, before adding it  
to the revlog. So in effect, every checkin comment would end with a  
bit of hex containing the signature.

To verify the signature: Get the revlog entry corresponding to the  
changeset, cut out the last sizeof(signature) bytes, then validate  
that those bytes form a valid signature of the remaining bytes.

--Jens