I
Ian Boyd
Is Microsoft going to releasing the algoritm used to generate the
x-cr-hashedpuzzle
and
x-cr-puzzleid
header entries for the new Postmark feature, so the entire world can benefit
from this idea? Or will you be keeping it a secret, so that only Outlook
users benefit?
Outlook 2007 adds to (some) outgoing e-mails the two header entries listed
above. This are computationally expensive to generate, and used as a
deterrant for spammers who are trying to send millions of spams at one time.
The receiving Outlook 2007 calculates the same "puzzle" to see if it
matches. If it's a valid postmark, it's a safe bet the e-mail isn't a spam.
Outlook 2007 only adds the postmark to outgoing messages that it thinks
might get classified as spam on the receiving end.
From http://office.microsoft.com/en-us/outlook/HA100625921033.aspx
<quote>
Sending e-mail
Before messages leave your Outbox, Office Outlook 2007 stamps each
message with an e-mail postmark. The postmark incorporates unique
characteristics of the message, including the list of recipients and the
time when the message was sent. As a result, the postmark is valid only for
that e-mail message. It takes some extra computer processing time to
construct the postmark. As a result, it takes a little longer for messages
to leave your Outbox. This is the computational cost incurred with using
Outlook E-mail Postmarking.
Receiving e-mail
When a recipient e-mail application that supports Outlook E-mail
Postmarking receives a postmarked message, it will recognize the postmark.
The postmark indicates to the recipient e-mail application that the message
is not likely to be spam and is taken into account when the message is
evaluated by the e-mail application's spam filter.
Why wouldn't spammers use this feature for their own benefit? Good question.
Here's why: Spammers rely on being able to send thousands of spam messages
per hour. To generate a postmark for each message and continue to send these
at the same rate as when they were sent without postmarks, spammers would
need to spend a significant amount of money to acquire more computers.
Therefore, spammers are less likely to send messages that are postmarked.
</quote>
Some of us want to incorporate this technique into our own e-mail client
programs - but it's only going to work if we all use the same algorithm. And
since Microsoft has taken the lead on this, it's their job to make their
algorithm open to the world.
keywords:
Outlook 2007 postmark x-cr-hashedpuzzle x-cr-puzzleid
x-cr-hashedpuzzle
and
x-cr-puzzleid
header entries for the new Postmark feature, so the entire world can benefit
from this idea? Or will you be keeping it a secret, so that only Outlook
users benefit?
Outlook 2007 adds to (some) outgoing e-mails the two header entries listed
above. This are computationally expensive to generate, and used as a
deterrant for spammers who are trying to send millions of spams at one time.
The receiving Outlook 2007 calculates the same "puzzle" to see if it
matches. If it's a valid postmark, it's a safe bet the e-mail isn't a spam.
Outlook 2007 only adds the postmark to outgoing messages that it thinks
might get classified as spam on the receiving end.
From http://office.microsoft.com/en-us/outlook/HA100625921033.aspx
<quote>
Sending e-mail
Before messages leave your Outbox, Office Outlook 2007 stamps each
message with an e-mail postmark. The postmark incorporates unique
characteristics of the message, including the list of recipients and the
time when the message was sent. As a result, the postmark is valid only for
that e-mail message. It takes some extra computer processing time to
construct the postmark. As a result, it takes a little longer for messages
to leave your Outbox. This is the computational cost incurred with using
Outlook E-mail Postmarking.
Receiving e-mail
When a recipient e-mail application that supports Outlook E-mail
Postmarking receives a postmarked message, it will recognize the postmark.
The postmark indicates to the recipient e-mail application that the message
is not likely to be spam and is taken into account when the message is
evaluated by the e-mail application's spam filter.
Why wouldn't spammers use this feature for their own benefit? Good question.
Here's why: Spammers rely on being able to send thousands of spam messages
per hour. To generate a postmark for each message and continue to send these
at the same rate as when they were sent without postmarks, spammers would
need to spend a significant amount of money to acquire more computers.
Therefore, spammers are less likely to send messages that are postmarked.
</quote>
Some of us want to incorporate this technique into our own e-mail client
programs - but it's only going to work if we all use the same algorithm. And
since Microsoft has taken the lead on this, it's their job to make their
algorithm open to the world.
keywords:
Outlook 2007 postmark x-cr-hashedpuzzle x-cr-puzzleid