According to a statement from Discovery, the suit was filed in U.S. District Court in Delaware, and claims Kindle infringes on an encryption technology patent held by Discovery founder John Hendricks since November 2007.

Discovery is seeking damages and royalties to compensate for "future infringement" of the patent, Reuters reported. Discovery, best known for its self-titled U.S. cable channel, calls Amazon out for violating U.S. Patent Number 7,298,851, "Electronic Book Security and Copyright Protection System."

According to Discovery, "Hendricks' work included inventions of a secure, encrypted system for the selection, transmission and sale of electronic books."

"The Kindle and Kindle 2 are important and popular content-delivery systems," said Joseph A. LaSala Jr., Discovery Communications' general counsel, in a statement. "We believe they infringe on intellectual property rights, and that we are entitled to fair compensation. Legal action is not something Discovery takes lightly. Our tradition as an inventive company has produced considerable intellectual property assets for our shareholders, and today's infringement litigation is part of our effort to protect and defend those assets."

Amazon did not respond immediately to a request for comment.

Amazon has had a target on its back almost since the day the Kindle 2 was unveiled in early February. After being criticized by the Authors Guild for the Kindle's text-to-speech feature, Amazon relented and said March 2 it would allow authors, publishers and other rightsholders to have the ability to disable the text-to-speech function.

"We strongly believe many rightsholders would be more comfortable with the text-to-speech feature if they are in the driver's seat," Amazon said at the time. "Therefore, we are modifying our systems so that rightsholders can decide on a title-by-title basis whether they want text-to-speech enabled or disabled for any particular title."