主题：【原创】快讯：Google可能退出中国？ -- 美人他爹

The smoking gun said to tie Chinese-speaking programmers to the Hydraq trojan that penetrated Google's defenses was a cyclic redundancy check routine that used a table of only 16 constants. Security researcher Joe Stewart said the algorithm "seems to be virtually unknown outside of China," a finding he used to conclude that the code behind the attacks dubbed Aurora "originated with someone who is comfortable reading simplified Chinese."

"In my opinion, the use of this unique CRC implementation in Hydraq is evidence that someone from within the PRC authored the Aurora codebase," Stewart wrote here.

In fact, the implementation is common among English-speaking programmers of microcontrollers and other devices where memory is limited. In 2007, hardware designer Michael Karas discussed an almost identical algorithm here. Undated source code published here also bears more than a striking resemblance.

The method was also discussed in W. David Schwaderer's 1988 book C Programmer's Guide to NetBIOS. On page 200, it refers to a CRC approach that "only requires 16 unsigned integers that occupy a mere 32 bytes in a typical machine." On page 205, the author goes on to provide source code that's very similar to the Aurora algorithm.

"Digging this a little deeper though, the algorithm is a variation of calculating CRC using a nibble (4 bits) instead of a byte," programmer and Reg reader Steve L. wrote in an email. "This is widely used in single-chip computers in the embedded world, as it seems. I'd hardly call this a new algorithm, or [an] obscure one, either."