"With its proprietary Office document format Microsoft is spreading rumours that ODF is somehow less secure. This is from the company that allows Office documents to embed arbitrary Visual Basic programs," said Schneier.
"This whole thing has heated up because the State of Massachusetts recently required public records to be held in ODF, which has put Microsoft into a bit of a tizzy."
The ODF is an attempt to make a universally readable document format. Concerns have been raised over 'corporate Alzheimer's', where documents are lost because they can no longer be read by current word processing software.
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