Watermarking returns+ graphical signatures

Matt Hampton matt at coders.co.uk
Fri Jul 13 09:35:34 IST 2007


Sattler, Tim wrote:
> Julian Field wrote:
> 
>> Firstly, the watermarking functionality has returned. But this time it
> 
>> is implemented differently so is safe from all patent problems. It is 
>> implemented in pretty much the same way that milter-null does it.
> 
> We have two MailScanner gateways both handling incoming and outgoing 
> mail, so the reply to a message does not necessarily come in the 
> same way the message went out. Does the watermarking functionality 
> work in such a setup as well?

Yes - the hash is calculated on the envelope from and then various
headers within the the message itself and combined with your secret and
a timestamp. It is then added as a header.

When the message comes back in it uses the envelope to and then looks
for the headers in the message body and checks the match and the expiry.

matt





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