From the press release from Langner Communications:
Press release – for immediate releaseGerman IACS security researcher Ralph Langner and his team have successfully identified code blocks that Stuxnet loads to PLCs – part of the actual attack code. The findings prove Stuxnet is directed sabotage involving insider knowledge. Langner assumes the target could be a nuclear power plant. Attack code and interpretation is published on www.langner.com/en.