The Chamberlain Group, Inc. v. Skylink Technologies, Inc., 381 F.3d 1178 (Fed. Cir. 2004) is a legal case heard by the United States Court of Appeals for the Federal Circuit concerning the anti-trafficking provision of the Digital Millennium Copyright Act (DMCA), , in the context of two competing universal garage door opener companies. It discusses the statutory structure and legislative history of the DMCA to help clarify the intent of the anti-circumvention provisions and decide who holds the burden of proof. It expresses that the statute creates a cause of action for liability and does not create a property right, and holds that as Chamberlain had alleged that Skylink was in violation of the anti-trafficking provision, it had the burden to prove and failed to show that access was unauthorized and its rights were infringed under the Copyright Act. As Chamberlain incorrectly argued that Skylink had the burden of proof and failed to prove their claim, the court upheld summary judgment in favor of Skylink. Background of the case This case involves two competitors that produce universal garage door openers (GDOs). Universal garage door openers are used when people want to replace or purchase a spare transmitter to open their garage door. They are designed to interoperate with existing GDO systems, regardless of model. Chamberlain markets a "Security+" line of GDOs which includes rolling code software that actively alters the transmitted signal by cycling through a series of strings (of which only some are able to open the door). This rolling code is designed to protect against a potential "code grabbing" attack where a nearby burglar may try to record the garage door opening signal. Chamberlain claims that the rolling code system makes it unlikely for a burglar to send a valid signal by replaying the recorded one. With rolling code protection, a garage door will open if and only if the transmitted code is not among the last 1024 used codes and it is among the next 4096 codes. The Security+ has additional functionality that will cause the GDO to resynchronize when two signals out of the acceptable range are transmitted in rapid succession. This was added in the case that homeowners use the same transmitter on multiple garage doors. In 1992, Skylink produced a universal transmitter called Model 39 that was designed to work for both rolling code and non-rolling code GDOs. The Model 39 bypasses the Chamberlain's