I am currently working on some security research that — if it works out the way I believe it will — would IMHO have made an interesting Blackhat Europe talk. I've been pushing to verify my ideas within the next week or so, as I believed the website which mentioned the CFP deadline as February, 1st. But apparently, the CFP is now closed »due to the large number of submissions we have received«. So what — they feared that closer to the CFP deadline, they would receive even more?