Abstract:
Watermark embedding is often used to identify multiple copies (Qi) of the same content (Q). Each copy (Qi) is provided with a different private watermark (Wi) which, for example, identifies the player on which that copy may be reproduced. Private watermarks can be hacked. Averaging two or more watermarked copies may cause any ofthe private watermarks to become undetectable. The watermark embedder (10) in accordance with the invention embeds a global (fixed) watermark (W) in addition to the private watermark (Wi). The global watermark is the same in each copy and therefore remains detectable. Its presence indicates that a private watermark shall be present as well. It can be used in a protocol like: no playback allowed if the global watermark is present and a private watermark is not found.
Abstract:
Multiple transform utilization and applications for secure digital watermarking. In one embodiment of the present invention, digital blocks in digital information to be protected are transformed into the frequency domain using a fast Fourier transform. A plurality of frequencies and associated amplitudes are identified for each of the transformed digital blocks and a subset of the identified amplitudes is selected for each of the digital blocks using a primary mask from a key. Message information is selected from a message using a transformation table generated with a convolution mask. The chosen message information is encoded into each of the transformed digital blocks by altering the selected amplitudes based on the selected message information.
Abstract:
Techniques for secure distribution of digital representations that combine encryption and watermarking. When a user at a client desires to download a digital representation, the user makes a request to a server for the digital representation, which encrypts the digital representation using a first key and downloads the encrypted digital representation to the user. Before the user performs any operation on the decrypted digital representation, a secret fingerprint watermark identifying the user is added to the digital representation. The fingerprint watermark is added either at the server or at the client and a copy of the fingerprinted digital representation is kept at the server. If the user makes an impermissible use of the digital representation, the secret fingerprint watermark can be used to identify the user. The request made by the user indicates the type of use that the user whished to make of the digital representation. If the use involves storage of the digital representation at the client, the server provides a second key that the client employs to encrypt the digital representation. If the user has permission to do so, the user may modify the digital representation and return the modified digital representation to the server for further distribution. In this case, the second key is used to encrypt the digital representation when it is sent to the server. The second key also serves as the user identification in the fingerprint watermark. If the user loses the second key, it can be recovered from the copy of the fingerprinted digital representation kept at the server. The first and second keys and any decrypted copy of the digital representation are kept in secure storage in the client.
Abstract:
The present invention relates to a method for certifying and subsequently authenticating original physical or digital documents. The concept of the evidence lies in the dual nature of a physical information item and a digital information item, one being the reference for the other that cannot be amended at the risk of the evidence being lost. For a physical original document (8) associated with a bubble seal (7) there is a corresponding time-and-date-stamped, proprietary paperless reference counterpart. For a time-and-date-stamped, proprietary digital original document (15) there is a corresponding reference counterpart in the form of a bubble seal (7).
Abstract:
The present invention relates to a method and apparatus for authenticating various types of digital certificates by using a text embedding method. The execution of the present invention is divided into two cases, one case including images in the certificate and another case not including the images in the certificate, according to the characteristic of the certificate. In the former case, a text embedding method is applied to images included in the certificate to embed a series of information text (a specific number of the certificate, and issuing organization, name of a person in charge, etc.) designated by a person who issues the certificate into the images. In the latter case, there is generated an image imperceptible to the human eye but having the same color as the ground color of certificate.
Abstract:
The work to be protected is digitized (10) and a baseline watermark is derived (12). A watermark offset vector is created (16) and then stored (18). The offset vector is added to the baseline watermark vector to generate a modified watermark vector (20). The baseline watermark vector is replaced with the modified watermark in the digitized work (22). And, finally, the watermarked work is returned to the original form (24).