Re: [Asrg] An Anti-Spam Heuristic

Steve Atkins <> Thu, 13 December 2012 02:12 UTC

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From: Steve Atkins <>
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Date: Wed, 12 Dec 2012 18:12:43 -0800
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To: Anti-Spam Research Group - IRTF <>
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Subject: Re: [Asrg] An Anti-Spam Heuristic
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On Dec 12, 2012, at 5:43 PM, Adam Sobieski <> wrote:

> Greetings. I have some ideas to prevent spam. A number of heuristics include increasing the computation required to send and receive an email, for example one to a few minutes of computation per email on desktop computers.
> One example of a heuristic, from that category, includes the use of a random number generator, seeded or salted with a combination of the sender's email address, the recipient's email address, and the date and time of the sending of the email. Then, in the described example, some amount of computation, measurable in minutes on a desktop computer, churns a stream of bits from the random number generator, in a buffer the size of which can be obtained from the size of the email, and with those bits in that buffer then utilizable by other heuristics. The recipient of an email can, with the sender's address, their own email address, the date and time of the sending of the email, and possibly other data, seed or salt an identical random number generator, churning a stream of bits, with an indicated amount of computation, measurable in minutes, to obtain the same bits in an identically sized buffer.
> By increasing the computation required to send and receive email messages, for example measurable in minutes of desktop computation, desktop graphics card computation, spam can be reduced as spammers would have to compute, per letter, per recipient, per email sending event, as described. In addition to, possibly in combination to, that category of heuristic, increasing the computation required to send and receive emails, the digital signing of email messages can be of use to preventing spam.

You might want to look at hashcash.

Brief summary of the conclusion: cannot work, as spammers have much easier access to free CPU cycles than do legitimate senders of mail.