"
The basic business decision that we decided to make here is that Microsoft is willing to trust governments
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Salah Dandan, Microsoft
The software giant is making the move to try to beat off rivals and strengthen its position in government markets.
Under an initiative called the government security program, the firm will allow governments and their agencies to examine the source code so they can improve the security of their software.
The Nato alliance and Russia have already signed up and Microsoft said discussions were taking place with more than 60 other governments and agencies.
Aware of the risks
The world's biggest software company has been put under pressure by rivals offering so-called open-source software which is available free and can be copied and modified.
Microsoft said it was confident governments would respect its intellectual property and the company said it was not worried about piracy or other infringements.
"The basic business decision that we decided to make here is that Microsoft is willing to trust governments and willing to partner closely with them," said Salah Dandan, the initiative's worldwide manager.
"We are fully aware of the risks, but cognisant that this program will help strengthen relationships with governments around the world."
Wider scope
This is not the first time that Microsoft has given details of its software blueprints, but the new plan takes the process much further.
In 2000 the software giant began its 'shared source initiative' and opened its source code to other companies and research and educational institutions.
But while it allowed users to refer to Windows code they were not allowed to change and redistribute it.