<div>
I am surprised there is not a php library, I had no lucky with Google. I will take a look at wordpress and try to understand it.
</div>


I am surprised there is not a php library, I had no lucky with Google. I will take a look at wordpress and try to understand it.

<div>
<div class="content wysiwyg-content">
Does anyone know of a PHP implementation of hashcash?<br />
<br />
Also, is there an estimate of what percentage of mail servers support hashcash?
</div>
</div>


Does anyone know of a PHP implementation of hashcash?

Also, is there an estimate of what percentage of mail servers support hashcash?

PHP Implementation of HashCash

Various techniques are used to prevent email spam (unsolicited bulk email). No technique is a complete solution to the spam problem, and each has trade-offs between incorrectly rejecting legitimate email (false positives) vs. not rejecting all spam (false negatives) - and the associated costs in time and effort. Anti-spam techniques can be broken into four broad categories: those that require actions by individuals, those that can be automated by email administrators, those that can be automated by email senders and those employed by researchers and law enforcement officials.