What is a digital signature and why would I want one?

September 2005

Imagine if there was one very easy thing, and if everybody on the internet did it, it would stop phishing, spam and viruses. Wouldn’t you do it?

Well. There is. And yet 80% of people never bother.

Configuring your email to use a digital signature is quick and easy.

What is a digital signature?

Digital signatures confirm that an email message really comes from the person who supposedly sent it and that it hasn't been changed.

It looks like a block of letters and numbers at the bottom of the email.

A digital signature is generated by your computer using an encryption key and the words in the message itself.

Why is a digital signature important?

A digital signature proves that your email comes from you. Its absurdly easy to “spoof” email addresses – to make it look like an email comes from you when it doesn’t About as easy as writing a return address on an envelope. So sometimes it’s difficult to recognize legitimate emails.

This is particularly important for business email – if you are relying on someone to provide information, you could be in big trouble if someone sends a fraudulent email with the wrong information. A fake customer might ask for your bank details, or a fake supplier might block a legitimate email and put their own bank details to send payment to. Other scams include pretending to be a company you deal with (your ISP for example) to get your username and password with that company or your credit card details. Phishers pose as coming from a reputable company you know – maybe your bank or other payment service.

You need to be certain the information is coming from the right place. A digital signature proves that the email did come from where it says it did, and that it hasn’t been altered during its journey to your inbox.

So if all email was digitally signed:

phishing, which relies on sending emails appearing to be from someone else, would no longer exist
spam, which is illegal but relies on no one knowing where it originated, could be tracked down at source and the offenders closed down
viruses also rely on no one knowing where they originated and the source would be very obvious and the offenders prosecuted.

How does it work?

What should I do now?

Leanne Smith is a founder of Sleek Services, a popular web solutions service that builds intelligent websites for intelligent people. For more articles or to see what an intelligent, high-traffic website can do for you visit www.SleekServices.net.