Google needs to keep hold of information about people's search history if it is to combat the sort of hacking it experienced in China last month, the company's top privacy lawyer, Peter Fleischer, said on Tuesday.
"The unprecedented hacking [of Google's networks] and the threat of similar such attacks in the future emphasised the importance of internal analysis of logs," Fleischer said.
He added that it is essential to find an appropriate balance between respecting users' privacy and maintaining network security. "To do that we need to open a dialog with the cybersecurity community. You can't discuss privacy in a vacuum," he said.
At the end of this week Google will submit a proposal to the Article 29 committee, a body comprising data protection officials from all 27 countries in the European Union, suggesting the creation of a panel of cybersecurity experts as well as privacy officials, Fleischer said.
The committee has asked all leading search engine makers to respond to its concerns about privacy by the end of January.
Microsoft said earlier on Tuesday that in response to the data protection officials' concerns, it is reducing the length of time it holds the IP addresses of users searching the Net through Bing, its recently launched search engine, to six months from 18 months at present.
In 2008 Google reduced the time it keeps full IP addresses to nine months from 18 months.
Microsoft claims to have gone much further in addressing data protection officials' concerns than its competitor, by promising to eradicate the whole IP address after six months.
Google only deletes a part of the IP addresses after nine months, leaving the parts that allow non-specific statistical analysis of the data. The part of the IP address that Google keeps hold of cannot identify an individual, Fleischer said.
"We find it incomprehensible that a company would throw away useful data when holding it poses no privacy threat," he said.
In its submission to the Article 29 committee Google has no intention of offering to further shorten the time it holds data, Fleischer added.
"We're committed to using data to both improve our services and our security measures for our users and protect their privacy, and we remain convinced that our current logs retention policy represents a responsible balance," he said.
Fleischer declined to comment on Google's response to the attack in China, which appeared to target the gmail accounts of Chinese opposition political activists.
The company has said it is considering pulling out of the Chinese market, one of the fastest growing markets for Internet search in the world, as a result of the politically motivated attacks on its system.