Microsoft has opened a Transparency Center in the Belgian capital, offering European governments a look at its source code.
The center, opened in Brussels last week, will "enable governments to review and assess the source code of Microsoft products and to access important security information in a secure environment," Microsoft said.
The center is the second such facility the company has built - the first was opened in Redmond last year - and will be open to governments that have signed up to the company's Government Security Program, which lets officials take a look at technical documentation, get Microsoft's intelligence data including details on future patches, and get more details on its cloud services.
However, the chief attraction for governments is likely to be the offer to check out the source code for a number of enterprise products and run their own analysis against it to, as Microsoft says, "help reassure customers that Microsoft products do not contain any hidden 'back doors'."
Claims about back doors in Microsoft software - rejected by the company - had been made long before leaked documents from Edward Snowden revealed the extent to which technology companies had been cooperating with the NSA.
To date, 42 agencies from 23 governments, including the European Commission, have signed up to the GSP, according to Matt Thomlinson, VP of Microsoft security.
"Governments around the world are under increased and increasing pressure to protect their citizens and critical assets from cyber-attack. Ensuring the defense of national infrastructure from online threats calls for a high level of openness and cooperation between public and private sectors," Thomlinson said.
Microsoft says it plans to open more Transparency Centers in Europe, as well as in the Americas and Asia, and increase the number of products whose source code is available for inspection.