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1 parent 39b1585 commit 2f77c579bbccd2a261222e513e4b3d376c33b218 Justin Thomas committed Feb 1, 2012
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+# Hashcash for Node
+
+Hashcash is a simple proof of work algorithm to prevent or slow down spam. It works by giving the requester a challenge in the form of a sha1 hash. After the hash is received the requesting client has four seconds to find a hash of the challenge + number that has three leading zeros. The client can find the challenge in the header: hashcash-challenge and add the answer to hashcash-answer.
+
+Using the middleware on an end-point in express will prevent the client from accessing the resource until an answer is found. A new challenge is created every four seconds.
+
+## How to Install
+
+ npm install hashcash
+
+## How to use
+
+First, require `hashcash`:
+
+```js
+var hashcash = require('hashcash');
+var express = require('express');
+var app = express.createServer();
+
+app.get('/protected',hashcash.middleware(),function(req,res) {
+ /* this will never get hit if the hashcash-answer is not present */
+ res.send('Success!');
+});
+
+var port = 8080;
+console.log('Listening on port: '+port);
+app.listen(port);
+```

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