BRUSSELS (Reuters) - Vint Cerf, a founding father of today's Internet, said on Thursday that European Union plans for new rules to fight crime on the Web risked clashing with existing EU privacy regulations.

Cerf, who helped develop the Internet in the early 70s shortly after graduating from Stanford University and now works for WorldCom, said more secure network systems were an immediate priority for the successful development of the ubiquitous Web.

He told Reuters in an interview that Internet traffic should be retained only for billing purposes and was too cumbersome to be stored for police investigations.

Privacy and the need to combat crime against the 407 million users of the Internet are concerns of the Commission -- the European Union's executive.

But Cerf said there is an inherent contradiction in the aim of the EU, arguing that the approach in combating cybercrime suggested in a recent Commission document could clash with the EU's strict requirements for privacy protection.

``The cybercrime document has provisions which are in conflict with other already agreed (EU) privacy laws,'' Cerf told Reuters. ''So there's plenty to do to sort that out.''

Cerf's comments came less than a week before a new, more comprehensive Commission communication on network security.

NET CONFIDENCE
European Union governments have listed confidence on the Internet as a key issue to achieve the target of making Europe the best knowledge-based society of the world by 2010.

The EU executive presented plans in March to improve the security of information infrastructures and combat computer offences, ranging from hacking and sabotage to dissemination of child pornography in the Internet.

To facilitate the work of law-enforcement authorities some governments are taking steps to require Internet service providers to store data that may be useful for investigations.

But Cerf said retaining even a small portion of the huge flow amount of data that moves daily over the Net for any lengthy period could prove costly and cumbersome for Internet service providers (ISPs).

``With my ISP hat on I can say that I don't know how I can do that,'' said Cerf, a senior vice president for U.S. telecom giant Worldcom.

``With many terabytes of data moving over the Net every day, accumulating any small fraction of that for any lengthy amount of time such as months or years is a very, very hard thing to ask,'' he said. A terabyte is a trillion bytes of data.

``My sense is that we shouldn't retain data at all unless it is needed for billing purposes,'' he said. EU law bans the retention of traffic data beyond that period.

Cerf said data retention may be unnecessary to help eradicate cybercrime using technology-enabled practices such as the interception of e-mails and data, or snooping on chat lines.

Such practices are banned except if there is a requirement from a law enforcement authority, he said.

``There are lots of ways to observe what's going on in the Net,'' he said. ``If someone (an authority) explicitly orders me to capture this information, I'll do my best to capture that.''

RUNNING OUT OF SPACE

Cerf said providing sufficient address space for the growing number of Internet-activated devices was another top priority because the number of Net servers and users had been growing at rates of between 80 and 100 percent annually since 1988.

He estimated 2.4 billion Internet-activated devices will be in use by 2004 and that by 2005 or 2006 the current Internet will be close to using up the current 4 billion available addresses.

He called for the industry to quickly take steps to upgrade the current structure of the Internet to a new system, known as IPv6, which can support an unlimited number of devices -- including cell phones.

``We need the address space,'' he said. ``If we have large numbers of devices operating we will start having problems if we are not using IPv6.''