In a method for embedding user information in webpages, user information of a user who logs into a target website is obtained. The user information is converted into color values. The color values are embedded in a target webpage of the target website. If a webpage is leaked, a user who leaks the webpage can be traced.

Methods and systems for tracking image senders using client devices are described herein. A computing system may receive an image containing a first watermark vector corresponding to a user account of an image sender. The computing system may convert the image to a frequency domain image that contains the first watermark vector. From the frequency domain image, the computing system may identify the first watermark vector. The computing system may compare the first watermark vector to each of a plurality of stored watermark vectors, each corresponding to a known user account, to determine a probability of a match. The computing system may determine the user account of the sender of the image by determining which of the plurality of stored watermark vectors has a highest probability of a match, and may send, to a workplace administrator platform, an indication of the user account.

Disclosed in this application are a method for embedding a watermark in video data and apparatus, a method for extracting a watermark in video data and apparatus, a device, and a storage medium. The method for embedding the watermark includes: acquiring a target image frame in video data; performing time-frequency transformation on the target image frame to obtain target frequency domain data, the target frequency domain data comprising a matrix formed by frequency domain coefficients; changing the frequency domain coefficients in the target frequency domain data according to watermark data to obtain watermarked frequency domain data; performing inverse time-frequency transformation on the watermarked frequency domain data to obtain a watermarked image frame; and synthesizing watermarked video data according to the watermarked image frame.

Image data depicting a 2D machine-readable code is up-sampled and compressed with a lossy compression process before being sent from a client device to a remote server for code reading. The remote server decompresses the sent information, extracts a payload from the machine-readable code, and causes result information to be sent back to the client device for display or other action. The up-sampling and compression operations performed on the client device can employ software instructions that are downloaded to, and executed by, browser software on the client device. Many other features and arrangements are also detailed.

In one aspect, a method is performed by a computing system that is in communication with a content-presentation device, where the content-presentation device is scheduled to perform, at a modification start-time, a content-modification operation that comprises modifying a modifiable content-segment that the content-presentation device is scheduled to receive. The method includes determining that the content-presentation device has detected, within a predefined time period after the modification start-time and during performance of the content-modification operation, a mismatch between reference fingerprint data representing the modifiable content-segment and query fingerprint data representing content received by the content-presentation device from a tuner device connected to the content-presentation device. The method also includes determining that the mismatch is due to the tuner device having modified the modifiable content-segment before the modification start-time and, in response to determining that the mismatch is due to the tuner device having modified the modifiable content-segment before the modification start-time, performing an action.

The present invention relate generally to signal encoding and decoding. One claim recites a method comprising: obtaining color image data or color video data, the color image data or color video data comprising an encoded signal pattern, the encoded signal pattern aiding detection of an encoded message, the pattern comprising first frequency components and second frequency components, the color image data or color video data comprising first color data and second color data, in which the first color data comprises the first frequency components encoded therein, and the second color data comprises the second frequency components encoded therein; combining the first color data and the second color data, said combining yielding combined color data; utilizing one or more processors or electronic processing circuitry, detecting the encoded signal pattern from the combined color data, said detecting yielding rotation and scale information; and using the rotation and scale information to detect the encoded message from the combined color data. Of course, other combinations and claims are provided too.

In one embodiment, a command is received from a video provider at a media rendering device, the command being a command to embed a subscriber ID in at least one video frame in a video stream. A random key, k is also received from the video provider at the media rendering device. An injective transformation is invoked for k and the subscriber ID, the injective transformation generating a sequence of pairs of: near-transparent patterns and corresponding time periods. Logical blocks of the at least one video frame in the video stream are overlaid with one of the near-transparent patterns for its one of the corresponding time periods. Related apparatus, systems, and methods are also described.

An image processing system for verifying that embedded digital content satisfies a predetermined criterion associated with display of the content, the image processing system a content embedding engine that embeds content in a resource provided by a content provider and that configures the resource for rendering, a rendering engine that renders the content embedded in the resource; an application interface engine that interfaces with the rendering engine and that generates a visualization of the resource and of the embedded content rendered in the resource; and an image processing engine that processes one or more pixels of the generated visualization of the resource and of the embedded content and the resource to verify that the specified visual element satisfies the predetermined criterion; and transmits verification data comprising an indication of whether the predetermined criterion is satisfied.

Systems, devices, and techniques are generally described to transmit image data. An image file including image data may be identified. The image data may be divided into a plurality of portions. The plurality of portions may include a first portion corresponding to a first position in the image data and a second portion corresponding to a second position in the image data. The image data may be modified to produce a shuffled image. The shuffled image may indicate that the first portion corresponds to a third position and the second portion corresponds to a fourth position. The shuffled image may be sent to a recipient computing device. The recipient computing device may render the first portion at the first position and the second portion at the second position to display the image data.

A system for making digital signatures includes plural signers determining cleartext bits to sign in response to a hash of a pre-image known to the respective signer and message. Another system uses one-way functions and a plurality of authentication paths per signature. A key information distribution system uses physical media, physical media revealing means, and changing the configuration of the physical media revealing means to reveal secret indicia to observers.