The lawyers have been earning their keep at Israeli-founded security company, Finjan in recent weeks. The company alleges that rival Secure Computing has infringed on a number of fundamental patents that lie at the heart of its web-filtering appliances.

Secure Computing denies the accusation, of course, though in legally conservative terms that make it hard to grasp whether they believe their case.

“Secure Computing takes the intellectual property rights of others very seriously. Secure Computing believes that its products have been developed with its own proprietary technology,” said John McNulty Secure’s CEO.

It’s all as clear as mud. But this phenomenon of companies suing each other over (probably) quite minor patent infringements is still troubling. A company has a right to defend its intellectual property, but the “patent legal” has become a near obsession among US tech startups.

My view? It’s hard to believe that a patent put to paper as long ago as 1996 can possibly have bearing on a security system ten years later. At the very least, it must have been drafted in very general terms, which makes it akin to Apple’s ridiculous “one click” suit against Microsoft of the early 1990s. Doubtless Finjan will disagree.

Has US patent law just turned into a nice little earner that restricts innovation? This suit could turn out to be significant – once we all find out what it’s really about in plain English.