Bethesda, Md.-based ContentGuard, which is backed by Xerox and Microsoft, said the digital ticket is similar to the way a ticket in the physical world allows people to gain access to a concert or a baseball game. With a digital ticket, people can view an e-book or listen to music for a specific number of times without being locked down to a single device.

ContentGuard said the digital ticket is a set of tamper-resistant codes that are put in a computer or embedded onto cell phone chips or plastic cards similar to credit cards. The code validates whether a person has certain rights to access specific digital content.
The patent comes as companies scramble to lay claim to a technology that people believe is crucial to the distribution of digital services such as online music-subscription services. Digimarc, which specializes in the authentication of digital or analog documents, this week received its 25th patent, which covers techniques for embedding digital watermarks into video and audio content.