Peer-to-peer: Shared property security pay

Peer-to-peer (P2P) technology has come a long way since the early days of Napster, and even the combined might of the recording and film industries has proved powerless to stop its rapid growth.

Research from the music industry's anti-piracy arm, the IFPI, shows that 11 per cent of UK internet users frequently engaged in file-sharing in 2004 and continued to do so in 2006, undeterred by the fact that 10,000 legal actions across 18 countries against large-scale P2P uploaders were launched last year alone.

However, it's not just those trying to sell CDs and DVDs that are affected by file-sharing. Businesses face several threats from client-side P2P technologies. Downloads of the original client software can be contaminated by spyware and Trojans, which are then unwittingly executed on a user's PC behind the corporate firewall. Once the application is uploading and downloading files, the content of the received files can be dangerous.

Malicious-code writers frequently use social engineering to ensure their files - which may be designed to open a backdoor into the users network - are in demand. Unless carefully configured, some popular filesharing software allows other peers to search the network as standard. Much of the content will infringe privacy laws, and all this activity can soak up an almost infinite amount of corporate bandwidth.

Another, if indirect, danger to enterprise is encryption cracking using distributed computing techniques - thousands of PCs linked together in a P2P network. For example, the 56-bit DES encryption algorithm was broken by brute force in less than 24 hours by a distributed network that was able to test 245 billion keys per second. At the time, DES was the strongest encryption algorithm the US government allowed for export.

The latest versions of BitTorrent, which has 135 million users worldwide, and emule, as well as eBay-owned VoIP and instant messaging/file transfer application Skype, use encryption to secure their traffic. "Encrypted traffic can be very worrying for IT managers," Bo Dines Larsen, technical director for Europe at internet traffic management solutions provider Allot Communications, points out.