Security researchers have developed a new cryptographic technique they say will prevent so-called stealth attacks against networks.

A stealth attack is one where the attacker acts remotely, is very hard to trace, and where the victim may not even know he was attacked. The researchers say this kind of attack is particularly easy to mount against a wireless network.

The so-called "delayed password disclosure" protocol was developed by Jakobsson and Steve Myers of Indiana University. The protocol allows two devices or network nodes to identify themselves to each other without ever divulging passwords.

The protocol could help secure wireless networks against fraud and identity theft, and protect sensitive user data. The technique will be particularly useful in ad-hoc networks, where two or more devices or network nodes need to verify each others' identity simultaneously.

Briefly, it works like this: point A transmits an encrypted message to point B. Point B can decrypt this, if it knows the password. The decrypted text is then sent back to point A, which can verify the decryption, and confirm that point B really does know point A's password. Point A then sends the password to point B to confirm that it really is point A, and knows its own password.

The researchers say that this will prevent consumers connecting to fake wireless hubs at airports, or in coffee shops. It could also be used to notify a user about phishing attacks, scam emails that try to trick a user into handing over their account details and passwords to faked sites, provide authentication between two wireless devices, and make it more difficult for criminals to launder money through large numbers of online bank accounts.

Jakobsson is hoping to have beta code available for Windows and Mac by the spring, and code for common mobile phone platforms later in 2005.

More info available here. ®

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