Internet domain registrar Go Daddy bought an unused root certificate, trusted by 99 per cent of browsers, from ValiCert a little over a year ago, and has since been developing the systems to make it work. It has now launched its offering.

Go Daddy will sell its 128-bit certificates for $89.95 per year, or $149.95 for two years. They're not the cheapest in the market, but they are cheaper than offerings from market-leading VeriSign and second-placed GeoTrust.

Domain registrars selling SSL certificates is a tested formula. Network Solutions pioneered the model when it was owned by VeriSign, and continues to do so now it is private. Register.com offers GeoTrust certificates.

VeriSign pioneered and has long dominated the SSL certificate market; smaller rivals have been snapping at its heels with only a small amount of success.

According to SecuritySpace.com, the fastest-growing competitor to VeriSign and GeoTrust is third-placed Comodo, with 5.3 per cent of the market compared to 1.2 per cent a year ago.

Comodo's relatively rapid growth may be due to its prices, which, at $139.95 for two years, are the cheapest of the major players. Comodo does not operate a root certificate: its SSL certificates look back to the old Baltimore Technologies root, now managed by BeTrusted.

It's not all about price, however. VeriSign has substantial time-earned brand value when it comes to SSL security, making it a difficult competitor to dislodge. Rivals consider its soft spots to be speed and support. So GeoTrust, for example, also competes on speed, offering 10-minute turnaround on certificate sales.

Go Daddy also hopes to outpace VeriSign. SVP Warren Adelman says that the company will deliver its certificates to new customers in a matter of hours, using a semi-automated process that relies on Whois and Dun & Bradstreet lookups and a manual phone-call verification.