Modifying the contents of a message

Unicorn.Consulting at
Fri Jan 27 00:55:57 UTC 2012

On 27/01/2012 1:49 AM, Jonathan Protzenko wrote:
> Hi everyone,
> Ever since I started reading the and 
> newsgroups, a recurring question about 
> Thunderbird has been "how can I modify the contents of a message" from 
> an addon? I recently (less than 7 days ago) replied to this question 
> twice, and my answer was basically:
> - inject a message in a local folder,
> - copy it to the destination folder,
> - remove the old message.
> I'm not sure there's a better way, but I guess not. My question is: 
> could we make that easier by implementing, say, in C++, 
> nsIMsgFolder::InjectMessageFromStream, making it of course scriptable? 
> The arguments are:
> - this is something an addon will want to do, and it seems legitimate 
> that they should want to do so,
> - it's better to provide a function for that than to have someone do 
> it real, real wrong.
> I'm not very familiar with that area, so I'd be interested in hearing 
> what others have to say on the matter :).
When I send my signed message to someone, or SMIME message, I would like 
to think that I don't have to produce my copy to prove what I sent to 
the recipient as a matter of course.  If your going to use this type 
thing, and I can understand where editing the subject may be valid, I 
would like to see the digital signature removed by Thunderbird if the 
content is changed.

Microsoft Outlook, which is the application sited most when people are 
asking for this, will not save an existing signed mail without you also 
having a digital signature,  I assume it replaces the signature as a 
part of the edit.

Certainly there is always the opportunity for a message to be modified 
in a text editor, but please lets try and make fraudulent modifications 
as hard as possible. As I understand it a digitally signed message is a 
legal document in the EU.  Should we be making the modification (without 
obvious forensic fingerprinting of the process) a simple process for 
add-on authors to execute.


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