Patent Application
20050204209
This application claims priority under 35 USC §119 to Finnish Patent Application No. FI 20040085 filed on Jan. 21, 2004.
1. Field of the Invention
The invention relates to digital rights management in electronic devices. Particularly, the invention relates to the use of an intelligent clock controller preventing the misuse of time limit protected digital content.
2. Description of the Related Art
Since the introduction of digital storage technologies more effective copyright enforcement has become an issue. Especially, the emergence of the Internet as an illicit distribution channel for copyright protected content has created a strong demand for new technologies in copyright protection. One such technology is the Digital Rights Management (DRM). The DRM is a common term for standards and proprietary systems where a given content item is augmented with information that specifies user rights associated with it. The content item may, for example, be an audio recording, video, picture, computer program or simply a document. The user rights may comprise various rules pertaining to the use of the content item. For example, a user may be given a time limit during which the content item can be presented, in other words, rendered to the user. Allowed number of listening times, allowed device identities and partial viewing rights are other examples of rules pertaining to the use of a content item. The DRM requires that the presentation device and the presentation software in it are not hostile, that is, they participate in the enforcement of digital rights. In the presentation device there is usually a DRM agent, or in other words, a DRM engine, which enforces the DRM rights and protects the content items from illicit copying. In order to avoid making a DRM protected content item available for copying, the content item may be encrypted while it is in transit from the network to the presentation device and while it is stored in the presentation device outside of the DRM engine, for example, on a hard disk.
One standard for the DRM is the one based on Open Mobile Alliance (OMA) DRM specification. The aim of the OMA DRM is to enable controlled consumption of digital media objects by allowing content providers to express content rights. The media objects are content items such as audio clips, video clips, pictures, Java applications and documents. Content items governed by rights are referred to as assets. In the OMA DRM content rights are expressed as document objects, that is, documents written using a Rights Expression Language (REL). In order to specify the rights pertaining to an asset it is associated with a REL object. The association between a REL object and an asset may be specified explicitly by mentioning the asset's identifier in the REL object or implicitly by providing the REL object in a same message together with the asset.
Reference is now made to
Reference is now made to
There are problems in a mobile terminal architecture such as illustrated in
The invention relates to a method of providing digital rights management in an electronic device, comprising a first clock. In the method a time attack event is detected in the electronic device; a barring time is increased in response to the time attack event; the barring time is checked at a request to present at least one media object; and the at least one media object is presented if that is allowed by rights associated with the at least one media object and the barring time does not exceed a predefined value.
The invention relates also to an electronic device providing digital rights management, which comprises a first clock. The electronic device further comprises: clock controller means configured to detect a time attack event and to increase a barring time in response to the time attack event; and presenting means configured to check whether the barring time exceeds a predefined value and whether a request to present at least one protected media object is detected by it.
The invention relates also to a computer program comprising code adapted to perform the following steps when executed on a data-processing system: detecting a time attack event in the electronic device; increasing a barring time in response to the time attack event; checking the barring time at a request to present a media object; and presenting the media object if it is allowed by rights associated with the media object and the barring time does not exceed a predefined value.
By a time attack event is meant herein an event related to the altering of time, the purpose of which is to bypass time-based protection associated with at least one media object.
In one embodiment of the invention, the electronic device comprises a second clock, which is adjusted based on time information from a network.
In one embodiment of the invention, a time attack event occurs when time in the first clock is updated and presentation of at least one protected media object is attempted within a predefined time period after the updating of time.
In one embodiment of the invention, a time attack event occurs if the last time signal received from a network indicates a time that is later than time in the first clock and presentation of at least one protected media object is attempted. The time signal from the network may be, for example, time information provided using UMTS Network Information and Time Zone service (NITZ). NITZ provides current time in notification messages that are sent to the electronic device. The electronic device may extract the time signal from content messages or rights messages that are delivered to it. The latest time signal from the network may be stored to a secure storage in the electronic device. The secure storage is not lost when the electronic device is powered off. The secure storage may be, for example, a flash memory. The last time signal received from the network is thereby made always available for the prevention of time attacks involving the manipulation of time in the first clock.
In one embodiment of the invention, a time attack event occurs when time in the second clock is ahead of time in the first clock and presentation of at least one protected media object is attempted.
In one embodiment of the invention rights that are associated with media objects are represented as rule objects or documents, for example, expressed in OMA REL format.
In one embodiment of the invention, the barring time is decreased regularly. The barring time may be decreased regularly at predefined time intervals by the clock controller means.
By a barring time is meant herein a time during which a user is prevented from starting time range protected media objects. Examples of time range protected media objects are objects that have associated with them OMA REL document objects, which specify a constraint element and a datetime element containing an end element and an optional start element. The elements are Extensible Markup Language (XML) elements.
In one embodiment of the invention, the predefined value associated with barring time is zero. It may also have a positive value.
In one embodiment of the invention, the barring time is allowed to become negative to a predefined limit. This is possible as the barring time is decremented by the clock controller means. The predefined limit may be, for example, −10 minutes. This means that the increasing of barring time does not immediately result in barring time that has a positive value, which might result in restrictions in the use of protected media objects, naturally depending on the predefined value associated with barring time. The negative barring time represents an extra tolerance or bonus time that is granted to the user of the electronic device in case there are no observed attempts to circumvent time range protection associated with media objects.
In one embodiment of the invention, the barring time is computed in the electronic device using a notion of behavior points. Barring time may be inversely proportional to behavior points. Negative behavior points are converted to positive barring time in direct proportion and positive behavior points are converted to negative barring time. For example, the conversion may occur so that behavior point balance B is converted to barring time T so that T=−C·B minutes. C is an arbitrary coefficient, the value of which is, for example, one. In this case the predefined value associated with barring time may also be presented as a threshold that is expressed as behavior points. The threshold may have a positive or negative value.
In one embodiment of the invention, the electronic device stores the behavior points in a secure storage, which is not lost when the electronic device is powered off. The secure storage may be, for example, a flash memory.
In one embodiment of the invention, the electronic device checks the availability of time from the second clock and it does not perform the step of checking the barring time if time is available from the second clock. The second clock may get time information from a network, for example, using UMTS Network Information and Time Zone service, which provides current time in notification messages sent to the electronic device. The second clock may get time from content messages or rights messages delivered to the electronic device. For example, the content or rights messages may be carried in UMTS or Global System of Mobile Communications (GSM) short messages to the electronic device. In one embodiment of the invention the first clock is a user interface clock in the electronic device. The user may alter time in the user interface clock at will. For example, the time may be altered via terminal set-up menus in the user interface.
In one embodiment of the invention, the first clock is also a clock, which receives timing information from a network that is not relied upon. This may occur in cases where the network providing timing information is a small and private local area network or a WLAN network. Therefore, the first clock is regarded as insecure.
In one embodiment of the invention, the step of increasing barring time is performed only if the electronic device presently stores rights, which have time range rules in them. The electronic device may perform a further check wherein it checks if it stores rights, which have time range rules that are affected by the observed updating of time in the first clock.
In one embodiment of the invention, the electronic device is a mobile device, for example, a UMTS terminal, a GSM terminal, a GPRS terminal, a WLAN terminal or a terminal within an arbitrary cellular radio system. The terminal may also be a fixed data network or telecommunication network terminal.
In one embodiment of the invention, the computer program is stored on a computer readable medium. The computer readable medium may be a removable memory card, magnetic disk, optical disk or magnetic tape.
In one embodiment of the invention, the electronic device is a mobile device, for example, a laptop computer, palmtop computer, mobile terminal or a personal digital assistant (PDA). In one embodiment of the invention the electronic device is a desktop computer or any other computing device.
The benefits of the invention are associated with improved digital rights management protection. With the invention it is now possible to avoid the circumvention of time based right control simply by manipulating a clock, which provides time for the electronic device.
The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
At step 410 intelligent clock controller 203 gets time from user interface clock 208. At step 412 intelligent clock controller 203 checks whether the timer D has expired. If the timer D has not expired at step 418 behavior points are decreased. If the timer D has expired, at step 414 intelligent clock controller 203 checks if behavior point balance 216 is less than a specified threshold value. The threshold value may be, for example, −10. Alternatively the threshold value may be, for example, 0. If behavior point balance 216 is less than the threshold value, it is an indication that user has a previous history of attempts to attack time range based DRM protection via malicious time updates. If behavior point balance 216 is less than the threshold value, the rendering of content, that is, the presentation of media object for the user is not allowed. The user is notified about the disallowing of content rendering at step 420. In one embodiment of the invention, if the presentation of a media object is disallowed due to the fact that behavior point balance 216 is less than the threshold value, MT 100 is put to a locked state, which involves that the presentation of media objects, which have time based rules associated with them, is not allowed in MT 100. In one embodiment of the invention MT 100 is put to the locked state also due to the fact that the checking of the timer D expiry reveals that it has not yet expired. The locked state may be released by receiving a specific unlock message to MT 100, for example, via network 110. MT 100 verifies the unlock message, for example, by checking whether it contains a proper unlocking key or by checking the origin of the unlock message. The unlock message may be authenticated by MT 100, for example, using data origin authentication. The unlock message may be carried to MT 100, for example, using a GSM short message or as an instant message. Alternatively, the locked state may be released by entering an unlocking code to MT 100 via user interface. If behavior point balance 216 is greater than the threshold value, DRM engine 202 is allowed by intelligent clock controller 203 to continue with checking REL object 214 that is associated with requested DRM protected media object 210. This is done at step 416.
In one embodiment of the invention, intelligent clock controller 203 and DRM engine 202 get automatically invoked by mobile terminal operating system whenever the timer I expires. In this embodiment intelligent clock controller 203 just increases the behavior point balance 216 with specified plus points, for example 10 points and exits. Therefore, in this embodiment there is no need to include the steps of starting DRM application, getting of user interface clock time, checking of behavior point balance 216, checking of REL object and any media object rendering related tasks to the increasing of behavior points.
At step 610 intelligent clock controller checks if behavior point balance 216 is less than a specified threshold value. The threshold value may be, for example, −10. Alternatively the threshold value may be, for example, 0. If behavior point balance 216 is less than the threshold value the rendering of content, that is, the presentation of media object for the user is not allowed. The user is notified about the disallowing of content rendering at step 616. In one embodiment of the invention, if the presentation of a media object is disallowed due to the fact that behavior point balance 216 is less than the threshold value, MT 100 is put to a locked state, which involves that the presentation of media objects, which have time based rules associated with them, is not allowed in MT 100. If behavior point balance 216 is greater than the threshold value, DRM engine 202 is allowed by intelligent clock controller 203 to continue with checking REL object 214 that is associated with requested DRM protected media object 210. This is done at step 612.
It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| FI20040085 | Jan 2004 | FI | national |
