Abstract: A method for configuring a biometric template protected authentication system wherein the desired classification threshold is first selected to optimize the trade-off between a false accept (FAR) and a false non match or reject rate (FRR) of the system, and then an error correcting code (ECC) used in the authentication process is chosen such that the number of errors which can be corrected is equal to or greater than the selected classification threshold. During authentication, the number of errors in a first codeword derived from biometric data associated with a physical object is determined and used in the decision process to accept or reject authentication.

Abstract: The invention provides a method for authenticating a physical object (OBJ) using a first helper data (W1) and a first control value (V1) associated with a reference object. The method comprises a step to generate a first property set (S1) using a noise compensating mapping (NCM) on information derived from the first helper data (W1) and a metric data (Y) associated with the physical object, and a step to establish a sufficient match between the physical object and the reference object using the first property set (S1) and the first control value (V1). The method further comprises a step to generate an update data (WUPD) for updating the first helper data (W1) using the first helper data (W1), the first property set (S1) and the metric data (Y). Also provided is a client terminal configured to carry out the method.

Abstract: The invention relates to a method of authentication of a physical object and an apparatus applying said method. The method uses a helper data (W1) and a control value (V1) associated with a reference object to generate a first property set (C1) using the helper data (W1) and a metric (Y) associated with the physical object. It further comprises a step to generate a second property set (S1) using a noise compensating mapping (NCM) on the first property set (C1), as well as a step to establish a sufficient match between the physical object and the reference object using the second property set (S1) and the first control value (V1). The method is characterized by a step that generates an error measure (ERR) by quantifying the noise removed by the noise compensating mapping (NCM) using the first property set (C1) and information derived from the noise compensating mapping (NCM). Error measure (ERR) is subsequently used for generating an authentication decision (D).

Abstract: A method for configuring a biometric template protected authentif ication system, in which the desired classification threshold (T) is first selected to optimize the trade-i off between FAR and FRR of the system, and then the ECC used in the authentif ication process is chosen such that the number (b) of errors which can be corrected thereby is equal to or greater than the selected classification threshold. During authentif ication, the number (b) of errors in a first codeword derived from biometric data associated with a physical object is determined and used in the decision process to accept or reject authentif ication.

Abstract: A secure forensic watermarking system is disclosed that distributes the same encrypted content to all users. The decryption key is different for each user, so that the decrypted content differs slightly from the original, i.e. is watermarked. Forensic tracking is possible by distributing unique decryption keys to individual users. The invention allows a forensic mark to be securely embedded in the compressed domain signal. In an embodiment of this invention, the content (x) and an encryption sequence (r) are entropy encoded using a homomorphic Huffman table. A homomorphic Huffmann table is a table H having the property that there exists an operation f( ) such that H-1 (f(H(a),H(b)))=a+b.

Abstract: The present invention relates to methods and apparatus for digital content distribution. A method of transferring digital content from a first entity (60) to a second entity (70) includes the steps of: a transfer control entity (50) transmitting a transmission key (KA) to the first entity, the first entity storing content data comprising digital content embedded with a first watermark (WA). The first entity applies the transmission key to the content data to remove the first watermark from the digital content and encrypt the digital content. The first entity transmits the encrypted digital content (CX) to the second entity. The transfer control entity transmits a receive key (KB) to the second entity and the second entity applies the receive key to the encrypted digital content to generate decrypted data comprising the decrypted digital content embedded with a second watermark (WB).

Abstract: There is described a system (10; 300) for processing an input signal (340) to generate a corresponding encoded output signal (380). The system (10; 300) includes a plurality of quantizing devices (30, 70; 350, 370) coupled in series, the system (10; 300 being configured in operation to reduce tandem quantization noise arising therein by: (a) analyzing the system (10; 300) to determine signal regions (290) in which tandem noise errors occur; and (b) modifying one or more earlier quantizing devices (30; 350) in the system (10; 300) with backward correction to reduce tandem noise arising therein from said determined signal regions (290), said one or more earlier quantizing devices (30; 350) not including a last quantizing device (70; 370) in series the system (10; 300).

Abstract: The invention provides a method for authenticating a physical object (OBJ) using a first helper data (W1) and a first control value (V1) associated with a reference object. The method comprises a step to generate a first property set (S1) using a noise compensating mapping (NCM) on information derived from the first helper data (W1) and a metric data (Y) associated with the physical object, and a step to establish a sufficient match between the physical object and the reference object using the first property set (S1) and the first control value (V1). The method further comprises a step to generate an update data (WUPD) for updating the first helper data (W1) using the first helper data (W1), the first property set (S1) and the metric data (Y). Also provided is a client terminal configured to carry out the method.

Abstract: Disclosed is a method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), for example an audio signal. The method comprises the steps of determining (301) a position where a predetermined property of the information signal exceeds a predetermined threshold, e.g. an attack position, and suppressing (302) the supplementary data signal in a predetermined neighbourhood of the determined position.

Abstract: Disclosed is a method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), for example an audio signal. The method comprises the steps of determining (107) a relative magnitude (g(n)) of a first property function (Mx(n)) of the information signal averaged over a region of a predetermined size and a second property function (Mwm(n)) of the supplementary data signal averaged over said region; and adjusting (407) the supplementary data signal according to the determined relative magnitude.

Abstract: The invention relates to embedding a spread spectrum watermark in a data signal as well as to detection of the embedded watermark. A data signal (4) is encrypted (15) or received in the form of an encrypted data signal (9), the signal being encrypted by modifying (3) it in accordance with one or more entries of a look-up-table (2) in which an encryption table (6) is stored. The encryption is carried out by a first computing device (15) such as a server device. The watermark is actually embedded while decrypting (13) the signal. This takes place in a second computing device (16), possibly in a client device, in a similar manner The client device employs a decryption table (8), which is a modified (i.e. watermarked) version of the encryption table (6). The decryption table may generated by the server and securely communicated to the client. The data signal is decrypted in accordance with entries of a look-up-table (12).

Abstract: There is described a system (10; 300) for processing an input signal (340) to generate a corresponding encoded output signal (380). The system (10; 300) includes a plurality of quantizing devices (30, 70; 350, 370) coupled in series, the system (10; 300 being configured in operation to reduce tandem quantization noise arising therein by: (a) analyzing the system (10; 300) to determine signal regions (290) in which tandem noise errors occur; and (b) modifying one or more earlier quantizing devices (30; 350) in the system (10; 300) with backward correction to reduce tandem noise arising therein from said determined signal regions (290), said one or more earlier quantizing devices (30; 350) not including a last quantizing device (70; 370) in series the system (10; 300).

Abstract: The invention relates to a system for detecting a watermark using informed detection. A first signal potentially having a watermark embedded is received (601) as is a second signal corresponding to the original signal. The signals are segmented (605) into symbol segments. For each symbol segment a first characteristic is determined (607) for a first section and a second characteristic is determined (609) for a second section in response to the first and second signals in those sections. Specifically, ratios between average envelopes are determined. Thus, the first and second characteristic is indicative of the variations of the envelope during a watermark symbol. A watermark symbol estimate is determined (611) from the first and second characteristic. A sequence of estimated watermark symbols is compared to reference watermark symbols and the presence of a watermark symbol is determined (615) depending on the comparison.

Abstract: System for performing telemetric measurements, comprising a plurality of mobile communication devices (100), each communication device (100) being provided with at least one sensor (110) and a sensor control section (120) for performing measurements, a cellular communication network structure for the mobile communication devices, a server provided with communication means for receiving measurement data from the plurality of mobile communication devices (100), and for sending measurement instructions to respective sensor control sections (120) of the mobile communication devices (100) wherein the sensor control sections (120) are programmable by the server.

Abstract: The invention relates to a method of searching for a watermark in a data signal, and to a watermark detector, such as a copy-control watermark detector. The search is conducted in order to find a watermark in content which possibly has been attacked and/or altered. The search is conducted by the steps of determining or setting a search space for the data signal, selecting a subspace of the search space, and searching for the presence of the watermark in the subspace. The subspace may be selected from a multitude of regions, the selection e.g. being based on a deterministic or probabilistic function.

Abstract: The invention relates to embedding auxiliary data in the form of a multibit payload in a host signal, and encrypting the associated detection key. Moreover, the invention relates to extracting the auxiliary data in the form of the multibit payload from a data signal. Auxiliary data is embedded in a host signal by the following steps. First a reference watermark is provided, subsequently an encrypted detection key associated only with the reference watermark is generated. The encrypted detection key may be a scrambled version of the watermark. In a further step, the multibit watermark is generated and a multibit payload is encoded into the reference watermark. Finally, the multibit watermark is embedded into the host signal.

Abstract: The invention relates to a watermark generation method for generating watermarks to be embedded in digital media, where said watermark is generated by combining at least two watermark patterns from a set of watermark patterns. The set of watermark patterns are divided into at least two subsets of watermark patterns, and the subsets are hierarchically related and the watermark patterns in said watermark are directly related watermark patterns. Directly related means that the watermark patterns are related like parent and child in a hierarchical structure e.g. a tree structure. Further, the invention relates to an apparatus adapted to generate watermarks to be embedded in media.

Abstract: In watermarking systems, hackers may try to remove the watermark using a so-called collusion attack. If the attacker has access to multiple identical signals with different watermarks (this typically occurs in electronic content delivery systems), simply averaging the signals will remove the watermark energy. A known solution to this problem is phase modulation. By modulating the phase of the signals, the averaging attack will cause phase cancellation to occur and annoying artifacts to be introduced. In the prior art, said phase modulation is carried out in the base-band domain, prior to watermark embedding. The present invention enables phase modification efficiently to be applied to transform coded signals, in particular DCT or MDCT coded signals such as MP3 or AAC audio signals, or MPEG2 video signals. The bitstream is partially decoded (4) and re-encoded (7).

Abstract: A method and a system for modifying a bitstream signal for enabling collusion resistant bitstream watermarking. The method comprises dividing a bitstream spectral signal X[k] of the bitstream signal bx into a first signal (302) and a second signal (304); multiplying the first signal (302) by a first modification signal (306) and outputting a modified first signal (314); performing a transform operation on said second signal (304) for obtaining a transformed second signal (308); multiplying said transformed second signal (308) by a second modification signal (310) and outputting a second modified signal (312); subtracting said second modified signal (312) from said first modified signal (314) and outputting a modified bitstream spectral signal X?[k] suitable for obtaining a modified bitstream signal b?x of said bitstream signal bx. Thus an efficient manner of applying a collusion resistant property for already encoded contents is provided.

Abstract: A system and a method for secure remote informed watermark detection making use of a side-information. The system in overview comprises a remote detector and a server computing system wherein a database with side-information assigned to specific descriptors of data signals is stored at the server computing system and wherein a remote detector intending to identify the watermark of a data signal will derive the descriptor of the data signal and subsequently contact the trusted server computing system in order to obtain the necessary side-information for the informed watermark detection.