An industry group called the Liberty Alliance has released specifications that let websites securely share the login data of customers.

The specifications will allow web users to sign in at one website and then use other affiliated sites without having to type in user names and passwords all over again.

The Liberty Alliance is pitting itself against Microsoft and its Passport system that performs a similar role.

Although the two sign-on systems do the same job they differ in their basic approach.

Sign here

Microsoft's Passport is a centralised database of user details that people can use to sign on to a wide variety of websites.

Newer versions of Microsoft's operating system nag people to set up a Passport account to get more out of the software.

Bill Gates has been talking up ".Net"

But many people are concerned about the security of Passport and the danger of having personal information in one place and under the control of one company.

Passport is part of Microsoft's ".Net" initiative, which aims to help companies use the web to streamline their organisation and to make it easier to set up web-based trading systems.

By contrast, the Liberty Alliance uses groups of federated websites that keep their own databases of customer details.

First products

A group of federated websites could include an airline, a car rental company, a travel agent and a hotel reservation firm.

If all the companies in this group are using the Liberty Alliance specifications, then someone signing in or logging on to their account at one of the group's websites will get access to their personal accounts at the other sites.

The Liberty Alliance specifications lay down how information should be passed among members.

Currently, 65 companies, including American Express, General Motors and Nokia, have signed up to the Liberty Alliance scheme.

The first products and websites that use the Liberty Alliance specifications are due to be released by the end of the year.