If you use the browser you can encrypt your web-based email using a handy extension called freenigma.
Welcome to freenigma!
freenigma adds privacy technology (with strong e-mail encryption) to your favourite webmail service.
Now you can decide for yourself which of your e-mails are private.
Today, all your e-mails are stored and sent around the planet in plain text. And today you have no control over what happens to your private or business e-mail conversations and you can’t prevent others from reading them. Get your privacy back! Encrypt your private and business e-mails to protect your freedom, privacy and your business secrets.
Exchange encrypted e-mails with your friends using Google Mail!
Actually, we support not only Google Mail, but all large webmail services: encrypt your e-mails in Google Mail, Yahoo! Mail and Hotmail and others. Exchange encrypted content with your friends and business partners. One freenigma account can be used for all supported webmail systems!
One of the challenges presented by web-based email applications like Gmail or Yahoo! Mail is that your mail is not encrypted. You therefore run the risk that mail you send could be intercepted and read (this risk exists for all email in truth). If you enjoy using Gmail or
According to Read/Write Web:
freenigma works by encrypting e-mails before they are saved and sent; they are then decrypted on the other end by the recipient. As noted in the FAQ, even if web-based email providers offer their own encryption services, freenigma is a service that works across all the web email systems.
freenigma is based on the popular GNU Privacy Guard (“GnuPG”) cryptographic software package and was developed with the business market in mind, at least to a degree. The creators of freenigma, freiheit.com, anticipate that more and more businesses will start outsourcing their email systems to companies like Google (you can read a bit more about how Google Apps for Your Domain can make this possible using Gmail here) and as they do this, they will need to be sure that their communications are secure. The fact that this solution is browser based means there is no need for expensive software to be installed on the desktop (although some may argue that there are good reasons to buy expensive software systems and to run them off a desktop machine as opposed to a browser extension and a web-based application).
(Source: Read/Write Web)