[lmm]

Brute force attacks are now 4x as effective as they were once thought to be, but they are not the limiting factor for AES' security, even at 126 bits. The most likely way for AES to be broken would be a new algorithmic innovation that worked against any key length, or a new kind of computer, or an implementation flaw, or... , and those things are not 4x as likely than they were.