Back to results
US 6,243,480 B1Granted
Digital authentication with analog documents
OwnerJian Zhao, Eckhard Kochinventors
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerJian Zhao, Eckhard Kochinventors
Estimating the term…
Techniques for protecting the security of digital representations, and of analog forms made from them. 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 an the agent may cause some or all of the code than an active watermark contains to be executed.
Apparatus which authenticates a digital representation from which an analog form may be made, the apparatus comprising:
Apparatus for determining authenticity of an analog form, the analog form containing first authentication information that is produced using semantic information present in the analog form and that is incorporated into the analog form such that the semantic information remains useful in the analog form to produce second authentication information which is comparable to the first authentication information,
A method of authenticating a digital representation from which an analog form may be made,
A method of determining authenticity of an analog form, the analog form containing first authentication information that is produced using semantic information present in the analog form and that is incorporated into the analog form such that the semantic information remains useful in the analog form to produce second authentication information which is comparable to the first authentication information, the method comprising the steps of:
Dependencies are inferred from the claim text.