AirDefense Inc and AirTight Networks Inc are each accusing the other of making misleading statements about their respective patent portfolios, with AirTight yesterday rebuffing AirDefense’s claims that its new patent is unenforceable.

Both companies claim that the other’s patents and applied-for patents are narrower in scope than their own, and each accuses the other of issuing misleading statements about the state of their patents or patent applications.

AirTight said last week that it had received its first US patent on wireless intrusion prevention systems. AirDefense immediately filed an interference action with the Patent and Trademark Office, trying to have the patent overturned.

Amit Sinha, chief technology officer of AirDefense, told us that the AirTight patent, numbered 7,002,943, is substantially the same invention as AirDefense claims in some yet-to-be approved patents, which were applied for earlier.

The ‘943 patent describes a Method and system for monitoring a selected region of an airspace associated with local area networks of computing devices. Essentially, it talks about how to accept or reject WiFi traffic based on security policies.

Sinha further claimed that AirTight was able to get its patents approved before AirDefense, despite applying later, because AirTight was making a very narrow set of claims that cover a subset of AirDefense’s own pending patents.

AirTight used a fast-track method to get its patent approved quickly. It had to pay the PTO more, and do more of the research into prior art, according to both companies.

It’s a quick and dirty patent, useful for marketing purposes, but it would not hold up in litigation, Sinha said.

That’s nonsense, according to AirTight’s vice president of marketing, Dennis Tsu. He said: It’s just as legally enforceable. AirDefense is deliberately trying to mislead the press and misrepresent the Patent Office.

Sinha pointed out that some of the prior art cited in AirTight’s patent are actually AirDefenses own patent applications. What this means depends who you talk to.

Sinha said it means AirTight is claiming a narrower set of inventions, almost a subset of AirDefense’s own claims. Tsu said it means the claims are broader, essentially building on and advancing earlier works.

Currently, only one patent has actually been issued, but AirDefense says it has three patents that have been allowed by the PTO, meaning they will become official numbered patents within a matter of weeks.

One of these allowed applications does appear to be pretty broad. Application number 20030236990, Systems and methods for network security, describes wireless intrusion detection systems apparently quite broadly.

Data corresponding communications transmitted over the wireless communication network are received. One or more tests are applied to the received data to determine whether a particular communication represents a potential security violation. An alarm may be generated based upon the results of the applied test or tests, it says.

AirTight’s Tsu claims the difference here is that AirDefense’s patents talk more about intrusion detection, IDS, whereas his own company’s patent and applications describe intrusion prevention systems, or IPS.

Tsu further claims that two of the AirDefense applications cited as prior art in AirTight’s patent have been rejected by the PTO. Sinha disputes this, saying AirDefense and the PTO are merely involved in quite normal back-and-forth negotiations.

Without time for a thorough review of all the patents and applications in question it’s tough to say whether either company is in the right here. What is clear is that not only is WiFi security set to become a hot market, but it will be one where intellectual property battles may be key strategic encounters.