JAVAScript Public Key Encryption Demo

First you need to generate a key pair. (Actually, it's a trio.) This is the slowest part. Pick how large a key you want. Larger keys are more secure, but take longer to generate, and somewhat longer to use (especially decrypting the orders). 512 bit key modulos (32 byte keys, ie p and q are 256 bits each) are still considered somewhat secure. My browser took almost 6 minutes to generate a key of this size. Try a smaller one first, like 8 bytes and multiply that time by 4 to see how long it might take for you.

Encrypting the orders takes very little time, maybe a second or two, but those decrypting will notice a definate lag (22 seconds for me).

Note that many browsers require you to NOT cancel the script after it is taking a while to generate the keys. I've tested this on InternetExplorer 5 (win). If you find it works/doesn't work with another browser, let me know. I've been told that Netscape is much slower than Microsoft for this type of thing.

How to use these:

Generate a key trio. For example, when I did I got:

• p*q: 187837067,451661
• d: 259144049,318819
• e: 17

Put a copy of crypto.js on your hard drive and on the server. Then add the following to your public script on your server:
<script> function encrypt() { document.form.text.value=rsaEncode([17], [187837067,451661],document.form.text.value) } </script>

And put the following in your private script (probably on your local hard disk -- not on the internet -- if your private key is found this whole thing is useless.)
<script> function decrypt() { document.form.text.value=rsaDecode([259144049,318819], [187837067,451661],document.form.text.value) } </script>

Ok, so you might want to do something more interesting than just put the data into document.form.text.value (this assumes you have a <form name="form"> in your document, by the way).

Enjoy!

John

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