Abstract: In embodiments, an apparatus for serial communication includes a transceiver, to receive a precoding request from a downlink receiver across a serial communication link, and to transmit data bits to the downlink receiver over the serial communication link. In embodiments, the apparatus further includes a precoder, coupled to the transceiver, to: receive scrambled data bits of a subset of the data bits to be transmitted, from a coupled scrambler, and, in response to the request from the downlink receiver, precode the scrambled data bits, and output the precoded scrambled data bits to the transceiver, for transmission to the downlink receiver across the serial communication link together with other unscrambled data bits.

Abstract: Techniques are provided for secure message passing. A sender process has a clear (non-encrypted) text message to pass to a recipient process as an encrypted message. The sender generates a message encryption key (MEK) for encrypting the message and sends the MEK to a first intermediary process, which encrypts the MEK. The sender uses the MEK to encrypt the message and passes both the encrypted message and the encrypted MEK to a second intermediary process. The second intermediary verifies that the sender is authorized to send messages and retains the encrypted message and the encrypted MEK. The second intermediary passes the encrypted message and the encrypted MEK to the recipient, which requests decryption of the encrypted MEK from the first intermediary. The first intermediary then decrypts the MEK and returns it to the recipient. Finally, the recipient decrypts the message using the MEK.

Abstract: Techniques for domain capture. In one embodiment, for example, a method comprises detecting an attempt by a personal user account to use the online service where the account is associated with an electronic mail address that belongs to an owner of a domain name service domain. Based on detecting the attempt, the online service prompts the particular personal user account to join a team of user accounts. Upon receiving an acceptance of the particular personal user account to join the team, the personal user account is offered an option between converting the personal user account to a team user account that is a member of the team or changing the electronic mail address associated with the personal user account to a different electronic mail address that is not owned.

Abstract: An audio decoder for providing a decoded audio information on the basis of an encoded audio information. The audio decoder has an error concealment configured to provide an error concealment audio information for concealing a loss of an audio frame, wherein the error concealment is configured to modify a time domain excitation signal obtained for one or more audio frames preceding a lost audio frame, in order to obtain the error concealment audio information.

Abstract: Techniques for domain capture. In one embodiment, for example, a method comprises detecting an attempt to create a personal user account with an online service that uses an electronic mail address that belongs to an owner of a particular domain name service domain. Based on the detecting, the online service prompts a user associated with the attempt to create a team account with the online service that is under management of the owner of the particular domain name service domain. Also based on the detecting the online service offers the user an option of creating a personal user account with the online service using an unowned electronic mail address.

Abstract: Systems and methods for remotely operating a data protection server are described. The data protection server is configured to perform predefined data protection operations for computing assets of an enterprise network. An email agent is installed on the data protection system to receive a specially-coded email message from an authorized user, where the specially-coded message includes an instruction for performing a predefined data protection operation. Upon receiving the email message and parsing it to extract the instruction, the data protection system initiates execution of the instruction.

Abstract: Systems and techniques for physical layer encryption (PLE) using beamforming. The techniques are based on the principles of Linear Amplification with Nonlinear Components (LINC) to produce a transmit signal with limited dynamic range. A masking signal is structured based upon a source data signal to produce a transmit signal with limited dynamic range, while providing a high degree of secrecy.

Abstract: A method for a machine or group of machines to watermark an audio signal may include receiving the audio signal, receiving a watermark signal, creating a spectral well on the audio signal by removing a portion of the audio signal corresponding to a frequency range, and inserting the watermark signal in the spectral well.

Abstract: Content screening operations are facilitated in devices that receive a content that is subject to screening obligations. When such a content is received at a device, a watermark extraction record is obtained and accessed to fulfill content screening obligations. Upon the receipt of such an extraction record, verification of the received extraction record is carried out based on a verification rate. If the verification is successful for an extraction record with permissive information, the verification rate is decreased, thereby reducing the processing load of the device. If the verification is unsuccessful, the verification rate is increased, which can adversely affect the processing load of the device.

Abstract: A secure optical communication system and method are disclosed. Short optical pulses are first modulated with data, then dispersed in time so that they spread out over multiple bit periods, then the desired code is applied to the dispersed pulses. The encoding may include frequency shifts or phase shifts or other. The dispersed optical symbols overlap in time so an applied code chip thus acts on multiple symbols simultaneously. There are generally multiple code chips per dispersed symbol. The coding device does not need to be synchronized to the data rate. Multiple wavelength division multiplexed channels may be encoded simultaneously. The signal propagates to a decoder that is synchronized with encoder to apply a complementary code thereby canceling out the effect of the encoder. The encoder and decoder can be realized by varying the wavelength of an optical pump to a parametric amplifier, allowing for a wide-band frequency shift.

Abstract: A local content server system (LCS) for creating a secure environment for digital content is disclosed, which system comprises: a communications port in communication for connecting the LCS via a network to at least one Secure Electronic Content Distributor (SECD), which SECD is capable of storing a plurality of data sets, is capable of receiving a request to transfer at least one content data set, and is capable of transmitting the at least one content data set in a secured transmission; a rewritable storage medium whereby content received from outside the LCS may be stored and retrieved; a domain processor that imposes rules and procedures for content being transferred between the LCS and devices outside the LCS; and a programmable address module which can be programmed with an identification code uniquely associated with the LCS. The LCS is provided with rules and procedures for accepting and transmitting content data.

Abstract: The invention relates to a chip for processing a content, comprising at least a microprocessor. Said chip includes an integrated non-volatile programmable memory for storing protection data and protected data, said protection data being intended to be used for authorizing/denying access to said protected data by said microprocessor under execution of a program. The invention allows to protect program and data dedicated to a chip-integrated conditional-access system and to protect features as external connections and downloaded data directly on the chip.

Abstract: A local content server system (LCS) for creating a secure environment for digital content is disclosed, which system comprises: a communications port in communication for connecting the LCS via a network to at least one Secure Electronic Content Distributor (SECD), which SECD is capable of storing a plurality of data sets, is capable of receiving a request to transfer at least one content data set, and is capable of transmitting the at least one content data set in a secured transmission; a rewritable storage medium whereby content received from outside the LCS may be stored and retrieved; a domain processor that imposes rules and procedures for content being transferred between the LCS and devices outside the LCS; and a programmable address module which can be programmed with an identification code uniquely associated with the LCS. The LCS is provided with rules and procedures for accepting and transmitting content data.

Abstract: In watermarked signal decoding, the embedded message is decoded by correlating the reference patterns with the watermarked signal. The watermark detector decides, depending on the size of the correlation result values, whether or not a given reference pattern was embedded. However, decoding watermarked audio or video signals is difficult if the link between the watermark encoder and the watermark decoder is not a digital one, for example an acoustic path. A re-sampler control unit controls the sampling frequency of a re-sampler, in connection with a watermark decoder that outputs, in addition to the watermark information bits, a corresponding confidence value that is derived from the correlation result and that is used for synchronizing the re-sampler sampling frequency with the original sampling frequency of the watermarked signal. The synchronization processing includes a search mode and a synchronized mode.

Abstract: User operates a selection switch to instruct temporary activation of an application. For the application of which the temporary activation has been instructed, a CPU of a console allocates resources necessary for signal processing by a DSP of an engine and for a parameter editing function of the console. In the DSP, a bypass parameter is set to ON. Thus, there is provided a state capable of accepting various parameter setting operation related to the application, but the signal processing based on the application program is prevented from being started in a substantive manner. In response to a full activation instruction of an application via a full activation instruction switch, the bypass parameter is set to OFF, so that audio signal processing based on the application can be started. In this way, preparatory work for setting parameters related to the application can be performed efficiently.

Abstract: A method of embedding data into an audio signal provides a data sequence for embedding in the audio signal and computes masking thresholds for the audio signal from a frequency domain transform of the audio signal. The masking thresholds correspond to subbands of the audio signal, which are obtained from a masking model used to compress the audio signal. The method applies the masking threshold to the data sequence to produce masked data sequence and inserts the masked data sequence in the audio signal to produce an embedded audio signal. A method of detecting data embedded in an audio signal analyzes the audio signal to estimate the masking threshold used in embedding the data and applies the estimated masking threshold to the audio signal to extract the embedded data.

Abstract: Secure communication of information is effected from a first party to a second party when the first party knows its own global location and the global location of the second party, and employs what essentially is an undiscoverable code signal that is broadcast to, and received by, both the first and the second parties. The first party securely communicates information to the second party by modifying the code signal with the information that is to be communicated and sends the modified code signal to the second party. Illustratively, the code signal is related to the Y component of a GPS signal.

Abstract: A process for distributing digital audio sequences according to a nominal stream format that include a succession of frames, each of which includes at least one digital audio block grouping a plurality of coefficients corresponding to digitally coded audio elements, including modifying at least one block of an original stream of sequences, in an adaptive manner on the original stream as a function of at least a part of characteristics representative of the structure, content and parameters of the original stream, a target profile and external events.

Abstract: A local content server system (LCS) for creating a secure environment for digital content is disclosed, which system comprises: a communications port in communication for connecting the LCS via a network to at least one Secure Electronic Content Distributor (SECD), which SECD is capable of storing a plurality of data sets, is capable of receiving a request to transfer at least one content data set, and is capable of transmitting the at least one content data set in a secured transmission; a rewritable storage medium whereby content received from outside the LCS may be stored and retrieved; a domain processor that imposes rules and procedures for content being transferred between the LCS and devices outside the LCS; and a programmable address module which can be programmed with an identification code uniquely associated with the LCS. The LCS is provided with rules and procedures for accepting and transmitting content data.

Abstract: Rather than downloading each content document on demand from the publisher location to the user site, at the publisher location, each content document is encrypted and then multiple encrypted documents are assembled into a distribution archive that is itself encrypted with a scheduled key. The distribution archive is then downloaded into a content server at the user site. When the content server receives the distribution archive, it decrypts the archive file and unpacks the encrypted documents. The scheduled key used to decrypt an archive file is included with an archive file that was sent previously to the user site in accordance with the subscription service. The scheduled key to decrypt the first archive file sent to the user is sent from the publisher to the user over a communication channel different from the communication channel used to send the archive file from the publisher to the user.

Abstract: Various quality versions of an electronic content are defined, and one or more distortion algorithms (22, 32) that are executable to generate a lower quality version of the electronic content by a distortion of the highest quality version (21, 31) are defined. Each quality version is selectively assigned a content key (CK) whereby an electronic content player (34, 70) will have the appropriate information when decrypting, decoding, and/or distorting the highest quality version (21, 31) of the electronic content.

Abstract: Watermarking of audio signals intends to manipulate the audio signal in a way that the changes in the audio content cannot be recognised by the human auditory system. In order to reduce the audibility of the watermark and to improve the robustness of the watermarking the invention uses phase modification of the audio signal. In the frequency domain, the phase of the audio signal is manipulated by the phase of a reference phase sequence, followed by transform into time domain. Because a change of the audio signal phase over the whole frequency range can be audible, the phase manipulation is carried out with a maximum amount only within one or more small frequency ranges which are located in the higher frequencies and/or in noisy audio signal sections, according to psycho-acoustic principles. Preferably, the allowable amplitude of the phase changes in the remaining frequency ranges is controlled according to psycho-acoustic principles.

Abstract: A marker is derived from an interaction between a person and an agent of a business and the agent's user interface. A part of a speech signal that corresponds to a portion of the person's special information is located with the marker. The speech signal results from the interaction between the person and the agent. The part of the speech signal that corresponds to the portion of the person's special information is rendered unintelligible.

Abstract: An electronic device comprising: a transport stream analyzer, the transport stream analyzer adapted to receive an encrypted MPEG transport stream and to output a program stream map stream, a conditional access table stream, a program stream directory stream, an encrypted video signal stream, one or more encrypted audio streams, an entitlement control message stream and an entitlement management message stream, all as MPEG packetized elementary stream data structures; and a packet multiplexer adapted to receive the output of the transport stream analyzer and to assemble the output of the transport stream analyzer into an encrypted MPEG compliant modified program stream comprised of packs of MPEG packetized elementary stream data structures and to output the encrypted MPEG compliant modified program stream.

Abstract: Methods and arrangements are disclosed for embedding and detecting a watermark in a cinema movie, such that the watermark can be detected in a copy made by a handheld video camera. The watermark embedder divides each image frame into two areas. A watermark bit ‘+1’ is embedded in a frame by increasing the luminance of the first part and decreasing the luminance of the second part. A watermark bit ‘?1’ is embedded by decreasing the luminance of the first part and increasing the luminance of the second part. It is achieved with the invention that the embedded watermark survives ‘de-flicker’ operations that are often used to remove flicker caused by the different frame rates of cinema projection equipment and consumer camcorders.

Abstract: A system and method of retrieving a watermark in a watermarked signal are disclosed. The watermarked signal comprises odd and even overlapped blocks where the watermark is contained in the even blocks. The method comprises, for each k-th even block, subtracting the two adjacent odd numbered blocks from the k-th even block of the watermarked signal to retrieve s *k(n), transforming s *k(n) into the frequency domain to generate S k(f), calculating a phase of S k(f) as ? (f) and a phase of Sk(f) as ?(f), calculating the difference ? (f) between ? (f) and ?(f), unwrapping ? (f) to obtain the phase modulation {tilde over (?)} k(f), and using a Viterbi search to retrieve the watermark embedded in {tilde over (?)} k(f).

Abstract: A system to generate an enhanced acoustic transmission signal includes a carrier signal generator to generate a carrier signal. A data signal generator is provided to receive data and to generate a data signal representing the data. A signal modulator is also provided to modulate the carrier signal with the data signal to form a modulated carrier signal at a carrier frequency. The system includes a masking signal generator to generate a masking signal to mask the modulated carrier signal from being audible by a human ear. An audio input device is provided to receive audio and to generate an audio signal based on the audio, wherein a frequency band surrounding the carrier frequency is removed from the audio signal. A signal adder is also provided to combine the modulated carrier signal, the masking signal, and the audio signal to form the enhanced acoustic transmission signal.

Abstract: A subscription broadcast security system for preventing theft of an encrypted program datastream utilizes an encryption protocol with steganographic supplementation. A decoder includes a decryption chip containing numerous decryption codes and an ID chip having a continually changing unique identification code for authenticating subscriber access. The ID chip and the decryption chip each receive decoding instructions through a combination of hidden data in the audio signal and from service provider communication directly with the ID chip.

Abstract: A digital video broadcasting receiver comprising a first input for receiving a first transport stream of data (TS#1) and a second input for receiving a second transport stream of data (TS#2), each transport stream comprising a plurality of packets and each packets having a header including a packet identifier PID. A de-scrambling device (12) receives packets of a transport stream for de-scrambling. A router (20) is arranged to pass packets alternately from the first TS#1 and the second TS#2 transport streams to the de-scrambling device 12 and to pass packets alternately to a first a second output, so restoring the first and second transport streams of data in a descrambled form.

Abstract: A method and apparatus utilizing prosody modification of a speech signal output by a text-to-speech (TTS) system to substantially prevent an interactive voice response (IVR) system from understanding the speech signal without significantly degrading the speech signal with respect to human understanding. The present invention involves modifying the prosody of the speech output signal by using the prosody of the user's response to a prompt. In addition, a randomly generated overlay frequency is used to modify the speech signal to further prevent an IVR system from recognizing the TTS output. The randomly generated frequency may be periodically changed using an overlay timer that changes the random frequency signal at a predetermined intervals.

Abstract: Audio signals, such as a music clip, are inserted with detectable watermarks. The inserted watermark can identify the content producer and provide a signature embedded in the audio signal and cannot be removed. The watermark can survive all typical kinds of processing and malicious attacks. The watermark can be implemented in a watermarking system that employs a covert channel encoder to layer an additional information data message or covert message on top of the watermark. The watermarking system can also include a permutation technique to further hide the watermark and hide the covert message within the watermark.

Abstract: A system and method of retrieving a watermark in a watermarked signal are disclosed. The watermarked signal comprises odd and even overlapped blocks where the watermark is contained in the even blocks. The method comprises, for each k-th even block, subtracting the two adjacent odd numbered blocks from the k-th even block of the watermarked signal to retrieve s*k(n), transforming s*k(n) into the frequency domain to generate Sk(f), calculating a phase of Sk(f) as ?(f) and a phase of Sk(f) as ?(f), calculating the difference ?(f) between ?(f) and ?(f), unwrapping ?(f) to obtain the phase modulation {tilde over (?)}k(f), and using a Viterbi search to retrieve the watermark embedded in {tilde over (?)}k(f).

Abstract: A local content server system (LCS) for creating a secure environment for digital content is disclosed, which system comprises: a communications port in communication for connecting the LCS via a network to at least one Secure Electronic Content Distributor (SECD), which SECD is capable of storing a plurality of data sets, is capable of receiving a request to transfer at least one content data set, and is capable of transmitting the at least one content data set in a secured transmission; a rewritable storage medium whereby content received from outside the LCS may be stored and retrieved; a domain processor that imposes rules and procedures for content being transferred between the LCS and devices outside the LCS, and a programmable address module which can be programmed with an identification code uniquely associated with the LCS. The LCS is provided with rules and procedures for accepting and transmitting content data.

Abstract: A system and method of generating a watermarked signal are disclosed. The system segments the signal into overlapping blocks using a window function and processes the overlapping blocks according to whether each block is odd- or even-numbered. The system windows the odd-numbered blocks, modulates the phase of each block in the frequency domain, transforms each modulated block in the time domain, windows each block transformed into the time domain and overlap-adds each odd-numbered block with each even-numbered block to generate the watermarked signal.

Abstract: A security apparatus and a security method for controlling electric devices by use of electronic mails. A modem receives an electronic mail sent from a sending side and stores the received electronic mail into a RAM of a controller. A CPU extracts certification information encrypted by a secret key of a user of the sending side and decrypts the certification information by use of a public key. Based on the decrypted information, the CPU determines whether the user of the sending side is authentic or not. Only when the user is found authentic, the CPU extracts a control command from the received electronic mail and stores the extracted control command into a RAM. Then, the CPU transmits an electronic mail to the sending side for confirming content of the control.

Abstract: The present invention provides an additional-watermark embedding apparatus for embedding predetermined additional data into original data. The additional-watermark embedding apparatus includes an adder for summing the original data and the additional data, a first amplifier for amplifying the original data according to a predetermined non-linear input-output characteristic, a second amplifier for amplifying the summed data supplied from the adder according to a predetermined non-linear input-output characteristic, a subtractor for taking the difference between the amplified data obtained by the second amplifier and the amplified original data obtained by the first amplifier, and an embedder for embedding modified additional data which is obtained by modifying the waveform of the additional data according to the original data and which is supplied from the subtractor into the original data.

Abstract: The invention provides apparatus and methods for embedding and recovering watermarking information based on host-matching codes. A code selector provides codes to be embedded in the host signal. The code selector associates distinct input data strings to be embedded into the host signal with distinct code sets. Codes from the associated code sets are selected to represent the input data strings based on an analysis of the host signal (i.e. “host-matching”). The code selector may associate the distinct input data strings with distinct code sets based on a predefined mapping. An embedder embeds the codes into the host signal to provide a watermarked signal. An extractor at a decoder extracts the embedded codes from the watermarked signal. A code interpreter interprets the codes to recover the data represented thereby. The interpreter may perform a many-to-one mapping of an extracted code to the associated data string.

Abstract: A system and method of generating a watermarked signal are disclosed. The system segments the signal into overlapping blocks using a window function and processes the overlapping blocks according to whether each block is odd- or even-numbered. The system windows the odd-numbered blocks, modulates the phase of each block in the frequency domain, transforms each modulated block in the time domain, windows each block transformed into the time domain and overlap-adds each odd-numbered block with each even-numbered block to generate the watermarked signal.

Abstract: An apparatus and method for displaying a copy-deterrent pattern (104) within a digital motion picture in order to discourage recording of the motion picture using a video camera or other sampling recording device. A copy-deterrent pattern (104) could be, for example, one or more symbols, a random pattern, a digital watermark or a text message (106). The copy-deterrent pattern (104) comprises a plurality of pixels within each frame of the digital motion picture, and the displayed pixel intensities are modulated at a temporal frequency using modulation characteristics deliberately selected to be imperceptible to human observers while simultaneously producing objectionable aliasing in any copy made using a video camera.

Abstract: Described herein is technology for inserting and detecting watermarks in signals, such as a music clip. In one described implementation, a watermarking system employs chess spread-spectrum sequences (i.e., “chess watermarks”) to improve the balance of positive and negative chips in the watermarking sequences. In another described implementation, a watermarking system employs an energy-level trigger to determine whether to skip encoding of a portion of a watermark within a given time span of a clip. If a large discrepancy in energy levels exists over a given time frame, then the frame is not watermarked, to avoid audible time-dispersion of artifacts due to spectral modifications. In another described implementation, a watermarking system begins encoding of a watermark at a variable position after the beginning of a clip.

Abstract: A system for modulating and demodulating signals that provides a new class of signal modulators and their corresponding demodulators. The modulation scheme embeds in an information signal a carrier signal by modulating the oscillatory rate of the carrier signal. The invention generalizes the possible carrier signals to any signal which can be generated by a dynamical system that have a known exponentially convergent observer, as in certain chaotic systems.

Abstract: Two El Gamal ciphertexts, which are input to a two-input two-output unit switching gates SW forming a permutation network, are randomized with a random number and randomly permuted, and a zero-knowledge proof, which proves the correspondence between the inputs and outputs of the switching gates SW, is output to a verifier without revealing the random number and the random permutation. A decryption unit decrypts ciphertexts from a unit switching gate SW in he last column through the use of a secret key, and proves in zero-knowledge the validity of the decryption without revealing the secret key. A verification unit verifies the proof of each unit switching gate and the proof of the decryption unit.

Abstract: A watermark embedder encodes auxiliary information, such as a binary message, into a host media signal by modulating message signals with two or more corresponding carrier signals to form a watermark signal and embeds this signal into the host. A compatible watermark decoder uses the carrier signals to demodulate the message signals from the watermarked signal.

Abstract: A data formatting method for embedding diverse data types in an electronic mail message includes the step of forming a network compliant electronic mail message header. Command blocks representing diverse data types are also generated. The command blocks representing the diverse data types are combined with a network compliant electronic mail message header into an electronic mail message. The electronic mail message is constructed to conform to network standards such that the command blocks representing the diverse data types are processed as textual information.

Abstract: A high-quality signal, for example, a unity-bit coded (DSD) audio signal having a 2.822 MHz bit rate (fs1) is converted to a lower sample rate (fs3) PCM signal by a sample rate converter (102). The watermark is embedded at the lower sample rate by a conventional watermark embedder (101) which is capable of handling signals at this lower rate. The watermark (WM) is not otherwise available. It is subsequently retrieved by subtracting (103) the unwatermarked signal from the watermarked signal, and up-sampled (104) to an intermediate sampling rate (fs2). The DSD signal is converted (110) to a PCM signal at said intermediate sample rate. The retrieved watermark is then added (107) to the PCM signal and the watermarked PCM signal is back-converted (120) to a unity-bit coded DSD signal. The arrangement preferably includes a compensation circuit (105) which compensates the information signal X′ for any (e.g.

Abstract: Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of predefined quantization values corresponding to an information symbol to be encoded. The amount of change required to modify the signal feature to the determined target quantization value is calculated and the cover signal is modified accordingly to so change the feature value over a predefined interval. Information symbols are extracted by the opposite process. In one embodiment, the predefined value is a short term autocorrelation value of the cover signal.

Abstract: Conventional decoding systems for scrambled audio-visual signals are improved by providing a dual-side local oscillator that functions as a high-side oscillator if the incoming RF signal is unscrambled and as a low-side oscillator if the incoming RF signal is scrambled. The result is that the unscrambled signal is reversed from an audio-over-video transmission configuration to an IF signal with a video-over-audio configuration, and a scrambled signal is maintained in a video-over-audio configuration, the video-over-audio configuration being the configuration required for proper reception and use of the signal by a television set. To function as both a high- and low-side oscillator, the dual-side oscillator has independent voltage control and does not follow the tracking filter associated with the tuner.

Abstract: The foregoing problems are solved and a technical advance is achieved by a computer-implemented system for providing a digital watermark in an audio signal. In a preferred embodiment, a audio file, such as a .WAV file, representing an audio signal to be watermarked is preprocessed using an algorithm of the present invention herein referred to as the “PAWS algorithm” to determine and log the location and number of opportunities that exist for inserting a watermark into the audio signal such that it will be masked by the audio signal. The user can adjust certain parameters of the PAWS algorithm before the audio file is processed. A/B/X testing between the original and watermarked files is also supported to allow the user to undo or re-encode the watermark, if desired.

Abstract: Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of predefined quantization values corresponding to an information symbol to be encoded. The amount of change required to modify the signal feature to the determined target quantization value is calculated and the cover signal is modified accordingly to so change the feature value over a predefined interval. Information symbols are extracted by the opposite process. In one embodiment, the predefined value is a short term autocorrelation value of the cover signal.

Abstract: Apparatus and methods are provided for embedding or encoding auxiliary signals into an analog host or cover signal. A replica of the cover signal or a portion of the cover signal in a particular domain (time, frequency or space) is generated according to a stego key specifying modification values to specified parameters of the cover signal. The replica signal is then modified by an auxiliary signal corresponding to the information to be embedded, and inserted back into the cover signal. Embedded auxiliary signals are extracted by generating replicas of received signals and correlating the replicas with the received signals.