Microsoft/Screenshot by CNET

Microsoft's ownership of Skype has placed it in the crosshairs of a patent lawsuit.

CopyTele, a company that calls itself "specialists in patent monetization and patent assertion," launched its suit today, alleging that some of the technology used in Skype violates patents owned by its subsidiary, Secure Web Conference Corp.

In its complaint, CopyTele is asserting the infringement of two U.S patents -- "Method and apparatus for securing e-mail attachments" and "Portable telecommunication security device," both granted in 2005.

Both patents concern secure Web-based peer-to-peer communications, such as those used by Skype. CopyTele CEO Robert Berman told CNET that the first patent applies to an exchange of information using public-key and private-key encryption with the users identified by their e-mail addresses.

The second patent covers a security device, meaning a device with a keyboard and microprocessor with multiple inputs and outputs. CopyTele's position is that a computer or smartphone that runs Skype or other Web conferencing software is within the definition of a security device and therefore violates the patent.

"New management joined CopyTele in September," Berman told CNET, "and we saw a lot of potential diamonds in the rough, and this is one of them. It's the second patent assertion campaign that we launched. We will continue to be active both in the Web conference space and in the other spaces in which we have patent coverage."

In January, CopyTele filed patent lawsuits against AU Optronics and E Ink Holdings regarding electrophoretic display technologies. Last month, the company purchased two more patent portfolios.

"We expect to launch additional assertion programs with significant revenue opportunities as we continue to mine [CopyTele's] patents and acquire additional patent portfolios from third parties," Berman said in a statement.

Microsoft declined to comment on the lawsuit.