Intertrust Technologies, a software and patent holding company based in Silicon Valley, announced today that it has sued Apple for infringing 15 patents relating to security and "distributed trusting computing." The allegedly infringing products include the iPhone, iPad, Mac desktops and laptops, Apple TV, iTunes, iCloud, and the App Store. So basically every product and service Apple sells.

Intertrust was founded in 1990 and claims to have a portfolio of over 250 granted patents and another 200 pending patent applications worldwide. At least part of its identity is as a patent holding and licensing company, but it also touts a research and development team, and various subsidiaries developing security software products. However, while that's all well and good, Intertrust's very DNA may be what's most interesting.

In 2003, after several years as a publicly-traded company, Intertrust transformed itself into a private joint-venture owned by Sony, Philips, and Stephens Inc. That's two tech big shots and an investment bank — a decent formula when creating a patent-licensing business. The only patent infringement case it seems to have pending now is the one it just initiated against Apple in northern California.

Apple is one of the last big holdouts

After a three-year court battle, Intertrust got Microsoft to take a $440 million license in 2004, and well-known companies like Samsung, Motorola, Panasonic, LG, HTC, Nokia, Adobe, and Pioneer are now identified as patent licensees. Even Nest Labs — a small but innovative player in the thermostat industry — is listed as one of its "current portfolio companies." It's not clear what that means exactly, but it looks like Apple is one of the last holdouts and Intertrust wants to change that. Some huge players in tech have concluded that there is some value in licensing these patents. While Apple isn't known for its conformist ways, time will tell if this particular patent portfolio is substantive enough to bring Cupertino into the mix.

Correction: an earlier version of this article indicated that Intertrust had concluded or settled several patent infringement cases over the last decade. However, only its case against Microsoft involved claims of patent infringement. All other patent-related cases were focused on invention ownership.