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_______________________________________________________________ _ . 1 Sending Device, such as Encoder, Recorder, Transmitter, Storage, etc. '
Receiving device, such as decoder, player, recorder, etc.
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Modifying and unmodifying aux. data for methods based upon PN sequences
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1 METHODS AND APPARATUS FOR ROBUST EMBEDDED DATA
This application is a continuation of U.S. patent application Ser. No. 09/404,291, filed Sep. 23, 1999 (U.S. Pat. No. 7,055,034). The 09/404,291 application claims the benefit of Provisional Patent Application Nos. 60/101,851, filed Sep. 25, 1998; 60/110,683, filed Dec. 2, 1998; 60/114,725, filed Dec. 31, 1998; and 60/126,591, filed Mar. 26, 1999; each of Which are hereby incorporated by reference.
This application relates to Provisional Patent Application Ser. No. 60/123,587 filed Mar. 10, 1999 and No. 60/126,592 filed Mar. 26, 1999, incorporated herein by reference. The application also relates to Utility patent application Ser. No. 09/404,292, filed on Sep. 23, 1999 (the same date as the 09/404,291 application) (now U.S. Pat. No. 7,197,156) entitled “Method and apparatus for embedding auxiliary information Within original data” by the same inventor of this application, Kenneth L. Levy, incorporated herein by reference.
This invention relates to the field of signal processing, and more specifically, to techniques for hiding auxiliary information Within original data.
BACKGROUND OF THE INVENTION
There are many techniques for embedding auxiliary information Within original data, also knoWn as Watermarking or steganography. The original data consists of perceivable media, such as audio, video, stills, etc. It is usually desirable for the embedded data to be non-perceivable, but some content degradation may be okay for some configurations. Several good algorithms have increased the embedded data’s ability to resist tampering and removal. One current use of embedded data in media is to include copy management information Within the embedded data. Unfortunately, With copy management schemes presented in the prior art, if embedded copy management information is removed the original data is susceptible to illegal distribution.
Embedded data techniques are susceptible to removal of auxiliary information for either of the folloWing reasons. First, the very nature of embedded data is incompatible With bit-rate reducing (a.k.a. compression) schemes, Which remove the non-perceivable aspects of the data such as done With MPEG compression. Since a key feature of any embedded data is the fact that it is non-perceivable, compression schemes Will act to remove the embedded data. Even if the embedded data is designed to survive the current compression technology, the next generation technology Will probably remove it. Bit-rate compression schemes are very important in the digital distribution of media, and receiving much research. Second, noise reduction techniques Will be able to remove embedded data. Noise reduction techniques are a hot topic, and used to restore old recordings. Since most nonperceivable embedded data is similar to noise, it Will be removed by these noise reduction techniques. Again, even if the embedded data is designed to survive the current restoration technology, the next generation technology Will probably remove it.
It is an object of this invention to increase the robustness of embedded data to attack. Attack is defined as getting around
What the embedded data is supposed to provide or prevent. Attack may include duplication, Which is defined as being able to replicate or impersonate the embedded data from one data segment to another. Attack may also include modification, Which is defined as changing the embedded data for a desired affect, such as from “no copying” to “copying alloWed”.
This invention includes tWo preferred embodiments describing novel Ways of using embedded data such that the embedded data is more robust to attack, labeled the enabling and registration process. In addition, multiple preferred embodiments improving the robustness of embedded data to duplication or modification are disclosed, labeled dynamic locking and unlocking.
The first preferred usage embodiment is the enabling process, Which involves using embedded data to enable an action, such as copying, playing or otherWise rendering. Thus, if the embedded data is removed by attack, the end-user has gained nothing because the original data has become unusable. Improvements in this process occur When the embedded data is robust against duplication and modification.
The second preferred usage embodiment is the registration process, Where the recording device embeds its registration in the data. In this embodiment, the recording device can refer to a physical device, such as a CD or DVD burner, or virtual device, such as an MP3 or AAC encoder. This registration process alloWs any illegal media to be traced back to the original oWner assuming that recording devices are registered When purchased. At the very least, the illegal media could be traced back to the specific recording device’s place of purchase, providing laW enforcement With a good starting point.
The dynamic locking and unlocking preferred embodiments improve the robustness of existing or future embedded data techniques to duplication and/ or modification. Dynamic locking causes the embedded data to be dependent upon the media by including one or both of the folloWing steps. The first step includes modifying the auxiliary information by the media. The second step includes encrypting the auxiliary information, possibly modified in the first step. The encryption technique could be RSA, DES or any appropriate algorithm. After dynamically locking the auxiliary information, it is embedded in the original data. Each step of dynamic locking provides its oWn independent advantages. HoWever, incorporating both steps produces auxiliary information that cannot be transferred betWeen media, modified, or created.
The dynamic unlocking process performs the inverse steps, assuming each specific step Was performed in the dynamic locking process. The first step involves decrypting the retrieved data. The second step involves unmodifying the output of the first step or the retrieved data directly, depending upon Whether the first step Was performed, and thus producing the original auxiliary data.
Five example utilizations of the enabling and dynamic locking process and apparatus are described briefly here and in detail beloW to aid in the understanding of both processes and apparatus. These utilizations include (1) distribution of compressed media such that it can only be played by the requester’s playback device, (2) using the presence of the embedded data to specify copy-once access, (3) protection of DVD media, (4) photo-card validation, and (5) sending secure secret messages.
In the first example utilization, a media player, such as a computer With MP3 softWare player, contacts an Internet site to doWnload media, such as a song in MP3 format. The player sends its unique identifier to the Internet site, Where the identifier is modified using the original data and the result is encrypted. The modified and encrypted identifier is then