OT: culprit in MIME recoding and breaking signatures

[Ian Zimmerman]

On 2018-11-23 09:47, Kurt Hackenberg wrote:

> > The winner appears to be Perl, namely the Mail::Audit module (and
> > whatever other modules it relies on).  I had a couple of scripts that
> > did gentle transformations of incoming mails.  The transformations were
> > supposed to only ever touch the headers, but I used a Mail::Audit object
> > to write back the entire message including the body.  I had complete
> > trust that the body would be bitwise identical to the original, but not
> > so.
> 
> What change did it make? I suppose it might use a different MIME
> transfer encoding, changing the representation but not the meaning.

It keeps the original QP encoding, but it recodes some (but not all)
sequences of spaces as =20, and vice versa.  Please see a recent thread
I started here for exact details, and also my blog:

https://very.loosely.org/itz-blog/

> Also, the most common variants of mbox are known to break
> cryptographic signatures, with the notorious ">From " escaping.

I stopped using mbox some years ago, and this could have been one of the
reasons (though the main reason was fragility when taking apart folders
and reassembling them).

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