A method for variable length decoding, the method including: receiving, in a default word length mode, at least one first data word having a default first word length; combining the received at least one first data word as a first portion of data; receiving, after the at least one first data word, a transition word indicative of transitioning to a variable word length mode; receiving, after the transition word, a first word length word indicative of a second word length; receiving, after the first word length word, at least one second data word having the second word length; and combining the received at least one second data word as a second portion of the data.

Various embodiments of the teachings herein include methods and systems for providing a speech-based service for the control of room control elements in buildings. Speech instructions are received by means of an audio device. The audio device is configured to analyze the received speech instructions, to convert them into corresponding operating commands for room control elements for the control of, in particular, HVAC devices (e.g. field devices) in a building and to pass them on to the corresponding room control elements. Before the receipt of the speech instructions by the audio device, the identity of the sender (user) of the speech instructions is anonymized by means of an anonymization service.

Provided is a data-coding apparatus that includes: a data-input line for receiving input data; a data scrambler having light sources coupled to the data-input line and modulated in accordance with the input data, and light sensors that receive light from the light sources; and at least one light-sensing processor coupled to the light sources and configured so as to selectively isolate light signals received from individual ones of the light sources based on at least one control signal input into such data scrambler. The light-sensing processor is dynamically controlled by the control signal(s) so as to rearrange words within the input data according to patterns that change in real time.

The codeword accessing method including: receiving a write data with M message bits; generating parity information with N-M bits based on an error correction algorithm and the M message bits, where N and M are positive integers; transforming the M message bits and the parity information to a scrambled codeword with N bits by a scrambling operation, where the scrambled codeword contains only a part of the M message bits; and writing the scrambled codeword into a memory device.

The codeword accessing method including: receiving a write data with M message bits; generating parity information with N-M bits based on an error correction algorithm and the M message bits, where N and M are positive integers; transforming the M message bits and the parity information to a scrambled codeword with N bits by a scrambling operation, where the scrambled codeword contains only a part of the M message bits; and writing the scrambled codeword into a memory device.

Aspects of the present disclosure describe scrambling of information for wireless communications to prevent deciphering or altering by unintended recipients. An example method may include generating, by a first device, a scrambling key based on at least one of a freshness parameter or a private key. The private key is known by the first device and a second device. The method also includes scrambling a payload based on the scrambling key at a physical layer. A packet includes the payload for wireless transmission from the first device to the second device via a shared channel.

A securely pre-coded orthogonal frequency division multiplexing (SP-OFDM) system includes a transmitter configured to transmit a secure transmit signal through a dynamic constellation and a receiver configured to recover the original signal from the received secure transmit signal. It is aimed to reinforce the physical layer security of wireless communications under hostile interference. Potential applications include 4G and 5G communication systems, ASTC3.0 HDTV systems, WiFi systems, and any future wireless systems that utilize OFDM.

A method and an apparatus for generating cover images for steganography are provided. The steganographic framework is designed based on an image generation system. The apparatus may encode a message to obtain a binary sequence. The apparatus may obtain a plurality of binary segments of a particular length based on the binary sequence. For each binary segment of the plurality of binary segments, the apparatus may select an image of a semantic content (e.g., a numeral digit) from a dictionary of images of random semantic contents (e.g., random numeral digits) based on the binary segment. The apparatus may combine the selected images to form at least a portion of a cover image denoting a combination of the semantic contents of the selected images (e.g., a plurality of numeral digits).

A communications system including a transmitter having a modulator that converts information bits to samples, a transmitter pseudo random number generator that generates a sequence of transmitter random numbers defining a time dilation function, and a transmitter time varying delay processor responsive to the samples and the time dilation function, where the transmitter time varying delay processor dithers the samples in time based on the time dilation function. The system also includes a receiver responsive to the dithered samples from the transmitter, where the receiver includes a receiver pseudo random number generator that generates a sequence of receiver random numbers in sync with the transmitter random numbers, a receiver time varying delay processor responsive to the receiver random numbers and the dithered samples, where the receiver time varying delay processor removes the dithering of the samples, and a demodulator for demodulating the samples to recover the information bits.

Detecting and monitoring legacy devices (such as appliances in a home) using audio sensing is disclosed. Methods and systems are provided for transforming audio data captured by the sensor to afford privacy when speech is overheard by the sensor. Because these transformations may negatively impact the ability to detect/monitor devices, an effective transformation is determined based on both privacy and detectability concerns.