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US 6,754,822 B1Granted
Active watermarks and watermark agents
AssigneeFraunhofer-Gesellschaft zur Forderung der angewandten Forshung e.V.
InventorJian Zhao
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AssigneeFraunhofer-Gesellschaft zur Forderung der angewandten Forshung e.V.
InventorJian Zhao
Estimating the term…
Techniques for protecting the security of digital representations, and of analog forms made from them are presented. The techniques include authentication techniques that can authenticate both a digital representation and an analog form produced from the digital representation, an active watermark that contains program code that may be executed when the watermark is read, and a watermark agent that reads watermarks and sends messages with information concerning the digital representations that contain the watermarks. The authentication techniques use semantic information to produce authentication information. Both the semantic information and the authentication information survive when an analog form is produced from the digital representation. In one embodiment, the semantic information is alphanumeric characters and the authentication information is either contained in a watermark embedded in the digital representation or expressed as a bar code. With the active watermark, the watermark includes program code. When a watermark reader reads the watermark, it may cause the program code to be executed. One application of active watermarks is making documents that send messages when they are operated on. A watermark agent may be either a permanent resident of a node in a network or of a device such as a copier or it may move from one network node to another. In the device or node, the watermark agent executes code which examines digital representations residing in the node or device for watermarked digital representations that are of interest to the watermark agent. The watermark agent then sends messages which report the results of its examination of the digital representations. If the watermarks are active, the agent and the active watermark may cooperate and the agent may cause some or all of the code than an active watermark contains to be executed.
Improved digital watermarking apparatus of the type that receives information and makes a digital watermark in a digital representation, the watermark containing the information and the improvement comprising:
A method of making a digital watermark comprising the steps of:
Improved digital watermark reading apparatus of the type which reads a digital watermark in a digital representation, the improvement comprising:
A method of reading a digital watermark comprising the steps of:
Improved apparatus for performing an operation on a digital representation, the apparatus having the improvement comprising:
An improved digital watermark in a digital representation, the improvement comprising:
A method of receiving information about a digital representation that includes a watermark that contains program code which is executed when an operation is performed on the digital representation and if executed, causes a message to be sent, the operation being performed by a program of which the digital representation is not a component and the method comprising the steps of:
A method of obtaining information about digital representations that contain watermarks, the method being employed in a network and comprising the steps of:
A method whereby a system which has received digital representations that contain watermarks may provide information about the received digital representations, the method being employed in a network and comprising the steps of:
A method of providing information about digital representations containing watermarks in a system which has access to a network and includes a watermark agent, the watermark agent including a program for reading a watermark and sending a message reporting a result thereof via the network, the method comprising the steps of:
Dependencies are inferred from the claim text.