Availability, security and privacy are the watchwords for Microsoft this year, according to an email sent from Bill Gates which managed to find its way into the public domain yesterday.

Dated 15 January, the Microsoft chairman's memo, apparently sent to everyone in the almost 50,000 strong company, lists security as the biggest concern for the Redmond giant.

"Every few years I have sent out a memo talking about the highest priority for Microsoft," wrote Gates. "Over the last year it has become clear that ensuring .Net is a platform for 'Trustworthy Computing' is more important than any other part of our work."

Gates acknowledged that, should Microsoft's reputation continue to be tarnished by security gaffes, "people simply won't be willing - or able - to take advantage of all the other great work we do".

He claimed that there is no "Trusted Computing" platform available today. "Trustworthy Computing is computing that is as available, reliable and secure as electricity, water services and telephony," he said.

But "computing falls well short of this. Microsoft and the computer industry will only succeed in that world if chief information officers, consumers and everyone else sees that Microsoft has created a platform for Trustworthy Computing."

Key to this strategy is the need to automate customer fixes. According to Gates, the availability part means that "our products should always be available when our customers need them. System outages should become a thing of the past because of a software architecture that supports redundancy and automatic recovery."

But Tuesday saw the end of a five-day server outage that prevented Microsoft users from downloading security updates.

Gates explained that the security part means that "the data our software and services store on behalf of our customers should be protected from harm and used or modified only in appropriate ways".

But last year's headlines were peppered with IIS vulnerabilities and viruses that propagated by exploiting bugs in Outlook.

The third part of the equation, privacy, states that "users should be in control of how their data is used, when and if they receive information". But in the past, Microsoft has come under fire over security concerns in its Passport service which is integrated into Windows XP. Passport is a key part of the .Net project.

"There are many changes Microsoft needs to make as a company to ensure and keep our customers' trust at every level," Gates acknowledged. "Flaws in a single Microsoft product, service or policy not only affect the quality of our platform and services overall, but also our customers' view of us as a company."