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Beat Spam Using Hashcash

Posted by timothy on from the variation-on-a-theme dept.

Shell writes "If they want to send spam, make them pay a price. Built on the widely available SHA-1 algorithm, hashcash is a clever system that requires a parameterizable amount of work on the part of a requester while staying "cheap" for an evaluator to check. In other words, the sender has to do real work to put something into your inbox. You can certainly use hashcash in preventing spam, but it has other applications as well, including keeping spam off of Wikis and speeding the work of distributed parallel applications." If you're specifically interested in hashcash for your mail server, Camram has some interesting ideas -- their Frequently Raised Objections page may be illuminating.

8 of 324 comments (clear)

  1. Hashcash got me arrested... by Anonymous Coward · · Score: 5, Funny

    Those damn police dogs can smell through plastic pretty well!

    1. Re:Hashcash got me arrested... by Infinityis · · Score: 5, Funny

      Maybe Winzip and Ziplock should merge. I think it'd be nice to have encrypted, password protected sandwich bags, but at 90% compression, I think the bread might not taste so good afterwards.

  2. HashCash? by Hatta · · Score: 3, Funny

    And remember, you can't spell "Budget" without "Get Bud".

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  3. now what? by Scythr0x0rs · · Score: 3, Funny

    You make me pay precious CPU time to e-mail my mother-in-law? you insensitive clods!

  4. I had to quit smoking... by RandoX · · Score: 5, Funny

    ...because I was out of hash cash.

  5. Re:Again? by AndroidCat · · Score: 3, Funny

    Yeah, it's not even a new Final Ultimate Solution to the Spam Problem (FUSSP).

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    One line blog. I hear that they're called Twitters now.
  6. How many numbers would that be? by Skapare · · Score: 3, Funny
    However, verifying a stamp requires just one SHA-1 computation. For use in e-mail, a 20-bit value is currently the recommended price: Senders need to perform about a million trials to find a valid stamp, which takes less than a second on the most recent CPUs and compiled applications. And it still takes only a few seconds on relatively old machines.

    Fur sail 2 u nou: 5 mil-leeun facter numberz

    Yuz cun b-u-l-k f4ster wit dis CD uv all-ready calcoolated leest uf numbors. Fer onlee $99.95, u getz ohver fiv milyun numz ant wee tos in freeee a miliun fresh A-O-L addys. Vizut us @ hotprimefactors.biz to ordur.

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    now we need to go OSS in diesel cars
  7. Hashcash....hmmmm.... by Shant3030 · · Score: 3, Funny

    reminds of what I used to call my student loans while in college...

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    100% Insightful