Marcus Kuhn

Researcher and computer security consultant Neal Krawetz first claims that the logos of As-Sahab, al-Qaeda’s media arm, and the US-based IntelCenter organization, which monitors terrorist activity, were added to a video released by al-Qaeda deputy leader Ayman al-Zawahiri at the same time, then retracts the claim when IntelCenter protests. Krawetz initially makes the claim during a presentation at a security conference about how analysis shows al-Qaeda videos are manipulated and backgrounds are added later. Krawetz says that the As-Sahab and IntelCenter logos have the same error level, so they must have been added at the same time. However, IntelCenter says that it did not add the As-Sahab logo and that just because two items in an image have the same error level, that does not mean they were added at the same time. Krawetz then tells a journalist that he retracts his initial claim and says that the IntelCenter logo has a different error level and was added later. The journalist comments: “However, in a taped interview I conducted with him after his presentation, he said the logos were the same error levels and that this indicated they were added at the same time. Additionally, after I’d written the first blog entry about his presentation, I asked him to read it to make sure everything was correct. He did so while sitting next to me and said it was all correct. He apologizes now for the error and the confusion it caused.” [Wired News, 8/2/2007] Krawetz’s method of analysis will attract some criticism. For example, Cambridge University expert Marcus Kuhn will say that Krawetz’s tools were designed for still images, not video, and could lead a user to believe that a video had been manipulated when in fact it had not. [Times, 8/6/2007]