Watermarking, what does it actually consist of ...

[Mikael Syska]

Hi,

I will look into in in the near future ... and that was tonight.

Just look and I guess i'm a little supprised allready ... if there are
any notes about it ( I'm not the biggest Perl programmer )

I converted the following to:
Friday, May 30th 2008, 08:05:51 converted to 1212134751 (GMT)
Which is not the same as in the mail ....

There seem to to a little diff ( 3 seconds, is this the scan time ? )
is expiry in that field just timestamp from the system ... since if
off by a few seconds ?

And what are the . ( dot ) denoting ? spilt between expiry and ?

The rest after the @ i guess is the md5 base64 string ?

.NET code ...
DateTime dt1 = new DateTime(1970, 1, 1, 0,0,0,0);
DateTime dt2 = new DateTime(2008, 5, 23, 10 - 2, 5, 51).AddDays(7);
TimeSpan ts = dt2 - dt1; // TimeSpan holds the TotalSeconds alias Unix Timestamp

does there seem to be any thing wrong here when trying to calc the
Expiry ? ( since it dont match the one in the mail )

This is my mail headers:
Return-Path: <root at mailtrap.dk>
X-Original-To: syska at mailtrap.dk
Delivered-To: syska at mailtrap.dk
Received: by spamtest.xxx.dk (Postfix, from userid 0)
     id CB4BF4A6456; Fri, 23 May 2008 10:05:51 +0200 (CEST)
To: syska at mailtrap.dk
Subject: test ... 123 med watermarking
Message-Id: <20080523080551.CB4BF4A6456 at spamtest.xxx.dk>
Date: Fri, 23 May 2008 10:05:51 +0200 (CEST)
From: root at mailtrap.dk (Charlie Root)
MIME-Version: 1.0
X-MailTrapper-MailScanner-Watermark: 1212134754.65295 at D1c/v4KnCSBJFymhGtSIPg
X-MailTrapper-MailScanner-Information: Please contact the ISP for more
information
X-MailScanner-ID: CB4BF4A6456.62A4F
X-MailTrapper-MailScanner: Found to be clean
X-MailTrapper-MailScanner-From: root at mailtrap.dk
X-Spam-Status: No

On Fri, May 23, 2008 at 3:52 PM, Matt Hampton <spamlists at coders.co.uk> wrote:
> Mikael Syska wrote:
>>
>> $expiry == is what ... days from the MailScanner.Conf converted to ???
>> and is this also added to the hash ... ???
>> $email == From mail taken from the header. But converted to a Unix
>> timestamp
>> $secret == From the MailScanner.Conf file
>> $date == also taken from the email header.
>> $msgid == also taken from the haeder.
>>
>>
>
> $expiry=unix timestamp of when the watermark expires
> $email= is the from email address (lower case) in the smtp transaction
>
> The rest is spot on.

Nice, its friday, and my brain aint totally cooked.

>>
>> so ... its joined with the $% ( the \ is escaping right ? )
>>
>> like "expiry$%email$%date(timestamp)$%sescret$%msgid" and the hash is
>> taken from that ?
>>
>> So what are the Expiry token ... ?
>>
>
> The expiry token is so that the code can throw away expired tokens without
> having to calculate the hash.

ohhh, saves some time :-)
>>
>> Sorry about these all these maybe stupid questions ... but I want to
>> do it right the first time ... so I'm 100% sure its the right way when
>> I'm trying to make the Watermark myself ... in a winblows system :-p
>>
>>
>
> That's OK - I wrote the code orignally so I know how it works so when
> explaining it I make assumptions that you know about it!

hehe ... :-) Every thing is also easier to know, when yourself is the
creator of it.

best regards
Mikael Syska