Method for generating a digital security item, in particular for watermarking moving images

Abstract

A method for generating a digital security item (126) is proposed. The method comprises the following steps i. providing a physical and / or chemical system (128) having a detectable, nondeterministic time behavior; ii. generating the digital security item (126) by - generating a digital image (116) of the physical and / or chemical system (128) at a time point by using at least one imaging device, and - associating the digital image with a unique timestamp relating to the time point, wherein the digital security item (126) comprises the generated digital image and the associated unique timestamp. The method may be used for watermarking moving images.

Description

[0001] Method for generating a digital security item, in particular for watermarking moving images

[0002] Technical Field

[0003] The invention generally refers to a method for generating a digital security item, a computer-implemented method for digital watermarking of a digital content, a computer-implemented method for authentication of digital content, a computer-implemented method for providing data security for different security levels, a digital security item, computer programs, computer-readable storage media and non-transient computer-readable media. The methods and devices according to the present invention specifically may be used in the field of data authentication and verification, and more specifically to systems and methods for authenticating moving images such as videos using watermarking. Other applications, however, are also feasible.

[0004] Background art

[0005] In recent years, digital video recording has become ubiquitous, whether for entertainment, security or myriad other purposes. This widespread increase in video recording has been spurred at least in part by a reduction in costs for recording equipment and the incorporation of video cameras into mobile devices (e.g., cell phones) favored by consumers. Corporations and businesses are also becoming increasingly reliant on video recording for security and communication. However, recorded video has a key drawback in that it is normally difficult, if not impossible, to reliably authenticate a video.

[0006] One of the main issues related to authentication is the determination of the time that a video was recorded. Video cameras are normally equipped with a timer, which automatically indicates the date and time of a recording. However, this information can be easily forged or otherwise falsified at the time of recording or in post-processing. To avoid this, users may place an artifact in the frame when the video is recorded that has a known date of creation (or publication). In theory, the presence of this artifact acts as a certification that the video was not created before the date of creation or publication of the artifact. However, this only provides an unreliable approximation as to the earliest date or time that a video recording may have been created and usually does not provide an upper boundary as to the latest possible date or time that the video may have been created.

[0007] US 2019 / 0297298 A describes a method for hiding images in synthetic videos and reveal them by temporal averaging. The visual masking method hides the input image both spatially and temporally. The masking approach consists of temporal and spatial pixel by pixel temporal variations of the frequency band coefficients representing the image to be hidden.

[0008] US 2018 / 0121635 A1 describes blockchain-based methods and systems for watermarking digital content. In an exemplary aspect, a method for watermarking digital content is provided, by receiving, by a processor, a data stream comprising audio and / or video content; receiving watermark data, by a processor, from a computing node communicatively linked to a blockchain-based distributed ledger; and applying at least one watermark to the data stream based upon the watermark data, wherein the watermark comprises at least one hash based on one or more data blocks stored in the blockchain-based distributed ledger.

[0009] US 8,867,782 B2 describes a system for detecting visibly hidden content on a print media in which image content is printed with one or more normal printing process visible colorants, and which further includes embedded hidden data printed with spectral edge markers. These spectral edge marker materials have a substantial spectral absorption just outside the human visible spectrum, either at the UV edge or IR edge, but only slight visible absorption which is masked by the visible colorants. Although the hidden data is nominally visually imperceptible, an image capture device having a visible spectral response from at least one spectrally distinct color imaging channel that extends into a spectral region just outside the visible spectrum where the spectral edge marker absorption occurs, can then detect the hidden data.

[0010] Further methods are known from H. Tao et al. "Robust Image Watermarking Theories and Techniques: A Review”, Journal of Applied Research and Technology, Vol. 12, February 2014, 122-138, JP 6133522 and JP 5998361.

[0011] US 2021 / 233204 describes watermarking media content, in combination with blockchain and distributed storage networks, prevents the proliferation of Deepfake content. Digital watermarks are embedded in the audio and video tracks of video clips of trusted content producers at the time the videos are captured or before they are distributed.

[0012] US 2013 / 336525 A1 describes a system for detecting visibly hidden content on a print media in which image content is printed with one or more normal printing process visible colorants, and which further includes embedded hidden data printed with spectral edge markers. These spectral edge marker materials have a substantial spectral absorption just outside the human visible spectrum, either at the UV edge or IR edge, but only slight visible absorption which is masked by the visible colorants.

[0013] Despite these achievements, a need exists for methods and systems that can reliably authenticate digital video recordings without requiring specific video content (i.e., in-frame artifacts associated with a given date or time), and which are resistant to falsification and manipulation.

[0014] Problem to be solved

[0015] It is therefore desirable to provide methods and devices which address the above-mentioned shortcomings of known methods and devices. Specifically, methods and systems shall be proposed which allow for reliably authenticate digital video recordings without requiring specific video content (i.e., in-frame artifacts associated with a given date or time), and which are resistant to falsification and manipulation. Summary

[0016] This problem is addressed by a method for generating a digital security item, a computer-implemented method for digital watermarking of a digital content, a computer-implemented method for authentication of digital content, a computer-implemented method for providing data security for different security levels, a digital security item, computer programs, computer-readable storage media and non-transient computer-readable media with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0017] In a first aspect, a method for generating a digital security item is disclosed.

[0018] The term "digital security item” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an element and / or feature configured for ensuring and / or which can be used for establishing forgery-proof data origin and / or authenticity and / or forgery-proof transfer of digital content via insecure channels. The digital security item may dependent on at least one security requirement. The digital security item may be used for fraud and tamper detection. The digital security item may be electronic information. The digital security item may be a digital code. The digital security item may be embedded into digital content such as an image and / or a video.

[0019] Specifically, the digital security item may be a digital watermark. The term "digital watermark” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to data which can be embedded into digital content in order to fulfill at least one security requirement. The security requirement may comprise one or more of data integrity, authenticity and authentication. The digital watermark may be a digital marker.

[0020] The present invention in particular proposes to use physical and / or chemical process as digital watermarks. Thus, instead of known watermarks, e.g. as described in indiaai.gov.in / article / the-art-and-algorithms-of-deepfake-ai-a-com- prehensive-study, which are based on algorithms, the proposed digital watermark is algorithm free and transforms a physical and / or chemical process into a digital watermark. Such a digital watermark is mathematically unclonable and non-invertible , therefore, not processable with computational approaches meaning super-computing resistance of e.g. quantum computing. The digital security item may be recognizable by a human being, e.g. visually, and / or may be recognizable by a machine such as a computer. For example, the digital security item may be a hidden digital security item. The hidden digital security item may be non-recognizable by a human being but only by a machine such as a computer.

[0021] The term "generating a digital security item” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process of creating a digital security item. The method may comprise generating a single digital security item or a plurality of digital security items.

[0022] The method comprises the following method steps, which, as an example, may be performed in the given order. However, a different order is also feasible. Further, it is possible to perform two or more of the method steps simultaneously or in a fashion overlapping in time. Further, it is also possible to perform one, more than one or even all of the method steps repeatedly.

[0023] The method comprises the following steps

[0024] I. providing a physical and / or chemical system having a detectable, nondeterministic time behavior; ii. generating the digital security item by generating a digital image of the physical and / or chemical system at a time point by using at least one imaging device, and associating the digital image with a unique timestamp relating to the time point.

[0025] The digital security item comprises the generated digital image and the associated unique timestamp.

[0026] The method may, in particular, be used for watermarking moving images such as at least one 2D video or at least one 3D video. The digital image in step ii. may be or may relate to a digital frame of a 2D or 3D video. The method may be performed continuously. The method may comprise generating a plurality of digital security items, in particular a plurality of digital images and corresponding timestamps. The method may comprise generating digital security items at the same frequency as a frequency of digital frames of moving images, such as of the 2D or 3D video, to be watermarked with the digital security items. For example, a frequency of digital frames may be 25 frames per second. The method may be repeated for each frame. This can ensure that for each video frame a unique digital security item is present for reliable watermarking. The watermarked video can be reliably authenticated by other parties later on.

[0027] Step I) comprises providing a physical and / or chemical system having a detectable, nondeterministic time behavior.

[0028] The term "providing” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to make available and / or using a data source, in particular the physical and / or chemical system. The term "system" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary set of interacting or interdependent elements forming a whole. The term "physical system” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary system comprising a collection of physical objects. The physical object may have some physical relationship. The term "chemical system” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary system of chemically interacting objects.

[0029] The physical and / or chemical system may be a data source, in particular a real world data source. The physical and / or chemical system may be an analog data source. The physical and / or chemical system may not comprise any virtual objects and / or may not be determined, defined and / or generated by using at least one algorithm, such as hash algorithm or random number generators, and / or simulation. The physical and / or chemical system may not comprise any virtual objects generated by computing.

[0030] The system may be a closed system having a defined and constant number of elements or an open system in which the number of elements may vary. For example, the system may be defined by elements within a vessel, a container, a tank, a chamber or the like.

[0031] The term "time behavior” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to time development of the system, in particular of elements of the system, from a first point in time to at least one second point in time, wherein the second point of time is different from and after the first point of time. The time behavior may refer to one or more of state of the elements of the system such as a chemical or physical status. The status may be defined by one or more of mixing, movement, flow, binding, location and / or orientation of physical objects, at least one physical property such as one or more of temperature, pressure, optical appearance, electrostatics, structural size of particles or molecules e.g. behavior of agglomeration or disintegration and the like. The term "nondeterministic time behavior” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to randomness or unpredictability of the time behavior. For transition for each of the elements of the system from the first point in time to the second point in time several possibilities exists. In case of particle based systems e.g. pigments, in small volumes, such as 1 mm3, about one billion particles can be present, which may lead to one billion faculty of different possibilities of local positioning. The time behavior may be one or more of non-predictable, non-computable, and non-determinable within a pre-defined time span and with available resources. The time behavior of the system may be not predictable by a machine such as a computer, in particular a quantum computer.

[0032] The term "detectable” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to at least one property of the system which changes from the first time point to the second time point can be detected by using at least one detector. The detectable, nondeterministic time behavior may be one or more of optically detectable, magnetically detectable, electrically detectable, electro-statically detectable.

[0033] The term "optically detectable” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to suitability of the system that changes from the first time point to the second time point can be detected by using the at least one imaging device. The elements of the system, in particular depending on its physical and / or chemical status, each may have at least one optical property such as one or more of diameter, shape, color including infrared color and / or ultraviolet color.

[0034] For example, the physical and / or chemical system comprises at least one element selected from the group consisting of: a system comprising a quantity of particles, wherein at least one subset of the quantity of particles has at least one different property than the remaining quantity of particles; a fluidic system comprising at least two fluids having different properties; a system comprising at least of one liquid and one quantity of particles having different properties; a system comprising at least of one gaseous material and one liquid having different properties; a system comprising at least of one gaseous material and a quantity of particles having different properties.

[0035] For example, the physical and / or chemical system comprises a system comprising a quantity of particles. The quantity of particles may comprise a mixture of particles of at least two particle subsets having different, in particular optical, properties. The quantity of particles may comprise a bulk of particles of at least two particle subsets having different optical properties. A particle size may be from 0.1 m to 0.001 m, preferably between 1 mm and 0.1 pm. The particle size may be defined by a cross-sectional diameter. For example, the size of the particle may be similar to the size of pixels of digital content which is intended to be watermarked with the digital security item. For example, the size of the particle may be identical to the size of the pixels. This can allow that every pixel can be assigned 1 :1 to a particle per frame. For example, the digital content may be in the range from 1 mm to 0.001 mm, e.g. for TV screens, for monitors of notebooks and computers. In particular, small particles behave completely randomly due to their physical properties and their interactions with each other, so that a simulation of particle movement is not possible.

[0036] For example, the physical and / or chemical system may comprise particles of different size. The particles may have a span of size due to their manufacturing process. Particle systems having particles of different size can further increase the randomness. For example, the physical and / or chemical system may comprise particles having different surface properties. Particle interaction may be induced by van-der-Waal forces resulting from surface roughness of the particles. Particle systems having particles having different surface roughness can further increase the randomness.

[0037] For example, the physical and / or chemical system may comprise particles having a very narrow span of particle properties such as size, shape, surface properties, e.g. in order to increase the reproducibility of the overall operational processing of the physical and / or chemical system. For example, the particle properties of the particles may be identical within 10 %, preferably within 5 %, more preferably within 1 %. The properties of the physical and / or chemical system may be adapted for the achievement of the required randomness and reproducibility of the overall operational processing of the physical and / or chemical system for the intended application. In particular, the span of particle properties may be adjusted accordingly.

[0038] For example, the physical and / or chemical system may comprise particles in fluidized state, e.g. via gas stream. For example, the particles may have properties according to Geldart-A definition (see "50 years of Geldart classification”, Ray Cocco et al. Volume 428, 1 October 2023, 118861). For example, the particles may be in fluidized state according to Geldart-B definition and / or Geldart-D definition. This can increase randomness due to larger variety of gas bubbles size and shape.

[0039] The optical property may be at least one property selected from the group consisting of: diameter, shape, color, density, flowability, magnetism, hydrophilicity, ionic and atomic radiation. For example, the size of the particles may be such that a desired number of particles per pixel of the digital image is present. For example, a size of one particle may correspond to the size of one pixel of digital content which is watermarked as will be described in more detail below. However, other embodiment are feasible.

[0040] The particles may be defined by at least one physical property such as one optical appearance, electrostatics, structural size of particles or molecules e.g. behavior of agglomeration or disintegration. The particles may have an identical or a different physical properties. For example the physical property may be a shape of the particles. The shape may be the geometric form and / or external morphology of the particle, e.g. characteristics such as roundness, sphericity, aspect ratio, or surface irregularity. The shape of particles may influence physical, chemical, or mechanical properties of a material or system, such as flowability or reactivity. For example, the particles may be round particles, e.g. balls. For example, the particles may have at least one edge.

[0041] For example, the system may comprise a quantity of particles. The quantity of particles may comprise a subset of black particles and a subset of color particles, e.g. RGB-color, particles such as one or more of red particles, green particles or blue particles. The quantity of particles may comprise from 70% to 99 % black particles, preferably more than 90% black particles. The term "black particle” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a particle with few or without exhibiting a color component. The term "black” may refer to black as defined in the CIE color space, e.g. see ASTM norm E308-01 , "Standard practice for Computing the Colors of Objects by Using the CIE System” or E308-22 "Computing the Colors of Objects by Using the CIE System”. The term "black” may refer to black as defined in the RGB or CMYK color space. Even other color spaces are possible. The term "color particle” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a particle having one or more of light absorption, reflection, emission spectra, and interference properties in the visible spectral range and exhibiting at least one color component. The term "color” may refer to color as defined in the CIE color space, e.g. see ASTM norm E308-01 , "Standard practice for Computing the Colors of Objects by Using the CIE System” or E308-22 "Computing the Colors of Objects by Using the CIE System”. The term "color” may refer to color as defined in the RGB or CMYK color space. Even other color spaces are possible. For example, the particle may be an RGB-color particle. The term "RGB-color particle” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a particle having one or more of light absorption, reflection, emission spectra, and interference properties relating to visual perception for humans as RGB-colors. The RGB-color of the particle may be red, green or blue.

[0042] For example, the particle system may comprise a particle collective of red and / or green and / or blue particles. In addition, the particle system may comprise black particles having an RGB color of (0,0,0). The black particles may have small optical deviations from the color black, e.g. due to reflection, or may have only very small color deviations due to the manufacturing process. Preferably, in a 24-bit RGB color space, the hexadecimal values of the black particles may be for each of the three color components below 50. The black particles may have similar or identical flow properties compared to the flow properties of the particle collective of red and / or green and and / or blue particles. The particle system may comprise more black particles than RGB particles.

[0043] The method may comprise setting and / or adapting the color values of the pixels of the digital image. For example, the RGB color values of all black particles may be set digitally to (0,0,0). This may be performed in order to cope for small optical deviations from the black color when generating a digital image. For example, the RGB color value of all red particles may be set digitally to (FF,00,00) in a 24-bit RGB color space. The same may be performed for the green or blue color when generating the digital image in a 24-bit RGB color space. The RGB color values of the green particles may be digitally set to (00, FF,00) or the RGB color values of the blue particles may be digitally set to (00,00, FF). This may be performed in order to cope for small optical deviations from the respective color when generating a digital image, in a second step. The ratio of colored versus black particles may be selected with respect to a resolution of the digital content. For example, the range of the ratio may be from 1 :5 to 1 :100000, preferably from 1 : 10 to 1 :10000, more preferably from 1 :20 to 1 :1000. The generating of the digital security item may comprise imaging at least one digital image of the particle system. The color information, in particular the RGB information, of pixels of the digital image may be used for digital watermarking, e.g. for merging with pixels of digital content, as will be described in more detail below.

[0044] The method may comprise applying at least one physical and / or chemical influence on the physical and / or chemical system thereby, in particular optically, detectable changing the state of the physical and / or chemical system. The influence may comprise one or more of shaking, mixing, stirring, vibrating, applying a gas flow, changing of a magnetic field, applying an electro-magnetic influence such as applying microwaves.

[0045] For example, the particle system may comprise black particles only. The method may comprise illuminating the particles by using at least one light source, wherein the illumination is timely changing. For example, the light source may change at least one emission wavelength of light generated by the light source. For example, the method may comprise moving the light source and / or the particles, e.g. via an oscillation and / or a rotation. The illumination of the black particles may be performed during movement of the light source thereby generating different patterns, images and the like.

[0046] Step II. comprises generating a digital image of the physical and / or chemical system at a time point by using at least one imaging device.

[0047] The term "digital image” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to digital information recorded by using the imaging device, such as a plurality of electronic readings from the imaging device, such as pixels of a camera chip. Thus, the image may be or may comprise at least one array of information values, such as an array of grey scale values and / or color information values. The image may be a single color image or a multi-color or colored image. The digital image comprises one or more of: a 2D image, a 3D image, a 2D video, a 3D video, content generated by using a tomographic technique.

[0048] The term "imaging device" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to at least one sensor device having at least one imaging element configured for recording or capturing spatially resolved one-dimensional, two-dimensional or even three-dimensional optical data or information. As an example, the imaging device may comprise at least one camera chip, such as at least one CCD chip and / or at least one CMOS chip configured for recording images. The imaging device, besides the at least one camera chip camera chip, may comprise further elements, such as one or more optical elements, e.g. one or more lenses. As an example, the imaging device may be a fix-focus camera, having at least one lens which is fixedly adjusted with respect to the camera. Alternatively, however, the imaging device may also comprise one or more variable lenses which may be adjusted, automatically or manually.

[0049] The imaging device specifically may be a color camera. Step ii. may comprise imaging the physical and / or chemical system by using at least one RGB-camera. For each pixel, color information may be provided or generated, such as color values for three colors R, G, B. A larger number of color values is also feasible, such as four colors for each pixel. Color cameras are generally known to the skilled person. As an example, each pixel of the camera chip may have three or more different color sensors, such as color recording pixels like one pixel for red (R), one pixel for green (G) and one pixel for blue (B) . For each of the pixels, such as for R, G, B, values may be recorded by the pixels, such as digital values in the range of 0 to 255, depending on the intensity of the respective color. Instead of using color triples such as R, G, B, as an example, quadruples may be used, such as C, M, Y, K or RGGB, BGGR, RGBG, GRGB, RGGB or the like. The color sensitivities of the pixels may be generated by color filters or by appropriate intrinsic sensitivities of the sensor elements used in the camera pixels. These techniques are generally known to the skilled person.

[0050] The term "generating a digital image” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to one or more of imaging, image recording, image acquisition, image capturing. The generating of the digital image may comprise capturing a single image and / or a plurality of images such as a sequence of images. For example, the capturing of the image may comprise recording continuously a sequence of images such as a video. The video may comprise moving images. The video may comprise a plurality of video frames, wherein each video frame comprises at least one digital image.

[0051] Information about the time point of generating the digital image may be known, e.g. by the imaging device, and / or may be determined e.g. by using a clock. Step ii. comprises associating the digital image with a unique timestamp relating to the time point. The associating may be performed by using at least one processor. The associating may comprise addition of the timestamp to the digital image, e.g. as meta data.

[0052] The term "timestamp” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to information about the time point of generating the digital image. The timestamp may comprise information about a date and a time of day e.g. with a resolution of seconds. The timestamp may have a format according to ISO 8601. The term "unique timestamp” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to that no two generated images have the identical timestamp. The method may comprise repeating steps i. and ii. and at different time points. The method may comprise generating the digital security items at the same frequency as a frequency of digital frames of a 2D video or a 3D video to be watermarked with the digital security items. For example, in case of a video, the frequency may be 25 frames per second. For example, steps I. to ii. may be repeated for each of the 25 frames. Other frequencies may be possible. For example, steps I. and ii. may be repeated every 1s, 5, 10, 30, or 60 seconds.

[0053] For example, the method may comprise recording a plurality of video frames. The timestamp may be recorded for each frame or a pre-defined intermittent time interval. The timestamp may be recorded for each video frame, e.g. continuously or at discontinuously, e.g. at a start of a video frame. For example, the intermittent time interval may be 25 times a second. For example, the intermittent time interval is selected from every second, every 5, 10, 30, or 60 seconds, or an arbitrary interval selected by a user. Other time intervals may be possible.

[0054] The digital security item comprises the generated digital image and the associated unique timestamp.

[0055] The method may comprise storing the digital image and the unique timestamp by a trusted authority. For example, steps I. and ii. are performed by the trusted authority. The term "trusted authority” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an entity or organization that is trusted or which is agreed upon to trust. The trusted authority may be a central location. The trusted authority may be a service provider such as a certificate authority.

[0056] For example, in case of using a particle system for generating the digital security item, due to the location and position of the particles in relation to each other, the exact time of recording each frame of a video recording of the particle system can also be derived. The time development, e.g. the mixing process, of the particle system may be monitored by the trusted authority, which, like an "atomic clock", sends the digital information of the continuous particle mixing to at least one recording device that want to generate a forgery-proof video recording.

[0057] The method comprises the trusted authority storing the generated digital security item in at least one database. The term "database" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an organized collection of data, generally stored and accessed electronically from a computer or computer system. The database may comprise or may be comprised by a data storage device. The database may comprise at least one data base management system, comprising a software running on a computer or computer system, the software allowing for interaction with one or more of a user, an application or the database itself, such as in order to capture and analyze the data contained in the data base. The database management system may further encompass facilities to administer the database. The database, containing the data, may, thus, be comprised by a data base system which, besides the data, comprises one or more associated applications.

[0058] The method comprises, e.g. the trusted authority, recording the generated digital security item as a non-fungible token (NFT) on a blockchain. The term "non-fungible token" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a unique digital identifier. The recording of the generated digital security item as NFT on a blockchain may be performed in accordance with ERC-721 und ERC-1155 standards.

[0059] The method may comprise the trusted authority transferring the generated digital security item via at least one secure communication channel to a user or a service provider. The digital security item may be used for watermarking digital content by the user or the service provider. The term "secure communication channel" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a communication channel configured for ensuring one or more of confidentiality, authenticity and non-repudiation of the data transfer. The secure communication channel may comprise using at least one cryptography technique such as one or more of data encryption using cryptographic keys, cryptographic hash functions, certificates, Transport Layer Security (TLS), a SSH protocol, and the like. The secure communication channel may comprise a physical transportation of the digital security item stored on a USB stick, hard drive and the like. The method may comprise establishing at least one secure communication channel which can be used for transfer of the generated digital security item. For example, the method may comprise exchanging a secret key using that key for communication.

[0060] In a further aspect, a digital security item is disclosed. The digital security item is generated by using a method for generating a digital security item according to the present invention such as described above or as described in more details below. With respect to definitions and embodiments of the digital security item, reference is made to the method for generating a digital security item as described in one or more embodiments above, or as described in more detail below.

[0061] In a further aspect, a computer-implemented method for digital watermarking of a digital content, in particular comprising moving images, is disclosed.

[0062] The term "computer implemented method" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a method involving at least one computer and / or at least one computer network. The computer and / or computer network may comprise at least one processor which is configured for performing at least one of the method steps of the method according to the present invention. Specifically, each of the method steps is performed by the computer and / or computer network. The method may be performed completely automatically, specifically without user interaction.

[0063] The method comprises the following method steps, which, as an example, may be performed in the given order. However, a different order is also feasible. Further, it is possible to perform two or more of the method steps simultaneously or in a fashion overlapping in time. Further, it is also possible to perform one, more than one or even all of the method steps repeatedly.

[0064] The method comprises a) providing the digital content; b) merging the digital content with a digital image of at least one digital security item generated by using a method for generating a digital security item according to the present invention thereby generating watermarked digital content; and c) one or more of storing, transmitting, or displaying the watermarked digital content.

[0065] With respect to definitions and embodiments of the digital security item, reference is made to the method for generating a digital security item as described in one or more embodiments above, or as described in more detail below.

[0066] The term "digital content" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a digital host medium, a digital cover medium and / or digital cover data. For example, the digital content comprises one or more of: a 2D image, a 3D image, a 2D video, a 3D video, content generated by using a tomographic technique. The digital content may comprise a video about an object, animal or person. The digital content may be forgery-proof digital content. The digital content may comprise a frame with a single digital image or a plurality of frames of moving images.

[0067] The term "providing the digital content" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to generating the digital content such as imaging, recording and the like, and to retrieving the digital content, in particular by downloading from at least one database.

[0068] The term "digital watermarking" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process of merging a digital security item and digital content. In case the digital content comprises a single digital image, e.g. a single frame, the method may comprise merging the single digital with a digital security item. In case the digital content comprises a plurality of frames of moving images, the method may comprise merging some or each of the frame of the plurality of frames with a digital security item respectively. The digital security items used for merging with the frames differ from each other.

[0069] The term "merging the digital content" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to one or more of combining the digital security item with digital content and / or embedding the digital security item into digital content and / or encoding the digital security item into digital content. For example, the digital watermarking may comprise digital watermarking the digital content Corgwith a digital security item W, using an encoding algorithm E, thereby generating watermarked digital content Cw

[0070] Cw=E{Corg, ).

[0071] For example, the encoding algorithm may comprise at least one addition. The merging may comprise adding of pixel color values of pixels of the digital content and pixel color values of the pixels of the digital image of the digital security item. Specifically, the digital watermarking may comprise spatial domain watermarking. The merging of the digital security item and the digital content may be performed as follows. The digital security item may be added directly to the pixels of the digital content. This can be performed by modifying the pixel values in a way that is imperceptible to the human eye. This technique may comprise embedding the watermark directly into the digital content's pixels. This can allow increasing difficulty for the watermark to be removed from the digital content, as it is part of the digital content's content.

[0072] An image resolution of the digital image of the digital security item may be selected to correspond to the image resolution of the digital content. The image resolution of the digital image may be at least similar to the resolution of the digital content.

[0073] For example, the complete digital content may be merged with the digital image of the digital security item. For example, a video, e.g. about an object, animal or person may be merged with the digital security item comprising another video recording, e.g. of a mixing movement of a particle system. These two video recordings may be converted into one video recording as a whole.

[0074] For example, at least one part of the digital content is merged with the digital image of the digital security item. For example, the method comprises detecting a face in the digital content by using at least one face detection algorithm. At least one part of the digital content comprising the detected face may be merged with the digital image of the digital security item.

[0075] The digital watermarking may comprise visible watermarking or hidden watermarking. The term "visible watermarking" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to overlaying the digital security item on top of the digital content such that it can be seen by anyone who views the digital content. Visible watermarking may, in particular, be used for branding or copyright purposes. The term "hidden watermarking", also called invisible watermarking, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to embedding the digital security item into the digital content such that it is invisible to the human eye. Invisible watermarking may, in particular, be used for identifying the source of the digital content and / or to track its distribution. For example, a wavelength content of the digital image of the digital security item is selected such that a difference between the digital content before merging and after merged is outside the range of perception of the human eye. For example, a light spectrum of the free-flowing particle system used for generating the digital security item is selected in such a way that the wavelength of the reflecting light does not disturb the viewer of the digital content. In particular, it is outside the range of perception of the human eye. The digital watermarking may comprise imperceptibly altering the digital content. The digital watermarking may be performed such that it does not cause perceptible changes to the digital content.

[0076] The digital watermarking may comprise using an encoder. The digital watermarking may comprise using one or more of secret or public keys and other parameters within the encoding algorithm. For example, a key may be generated that is used to encrypt the digital security item. The key may allow ensuring that the digital security item cannot be removed or tampered with. This key may be kept secret and may be used to decrypt the digital security item when it needs to be verified. A decoder may be used for detecting the digital security item in the watermarked digital content and for verification of the digital security item. To verify the digital security item, the same key that was used to encrypt it is used to decrypt it. The decrypted digital security item may then be compared to the original digital security item to ensure that they match. If they match, the digital content may be considered authentic.

[0077] The digital watermarking may comprise irreversibly embedding the digital security item into the digital content. For example, the merging in step b) may comprise robust watermarking. Robust watermarking may allow surviving various forms of intentional or unintentional attacks. This technique may comprise the following steps. The digital security item may be embedded into the digital content by modifying specific elements of the data of the digital content. The modifying may comprise altering the pixel values, modifying frequency domain coefficients, or manipulating other features of the digital content.

[0078] Other embodiments, however, are feasible. For example, the digital watermarking may comprise fragile watermarking. This technique can allow detecting any changes or tampering that may have been done to the digital content. The watermark may be designed to be very sensitive to any changes in the digital content, making it clear if the digital content has been altered in any way.

[0079] For example, as outlined above, the particle system may comprise a particle collective of red, green and blue particles and an amount of black particles with an RGB color of (0,0,0). The generating of the digital security item may comprise imaging at least one digital image of the particle system. The color information, in particular the RGB information, of pixels of the digital image may be merged with the color information of the pixels of digital content. The digital image and the digital content may have identical pixel numbers such that each pixel of the digital image has a corresponding pixel in the digital content. However, other options may be feasible. The color values of the pixels of the digital security item may be added to the color values of the corresponding pixels of the digital content, thereby generating a watermarked digital content. By merging with the pixels of the digital security item, the color value of the pixels of the digital content may get a maximum color portion of 255. For example, if a pixel of the digital security item having a color value of blue (0, 0, 255) is merged with a pixel of the digital content having a color value of green (0, 100, 0), the final pixel of the watermarked digital content may have the color value (0, 100, 255).

[0080] The merging may be performed by using at least one processor. The term "processor” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary logic circuitry configured for performing basic operations of a computer or system, and / or, generally, to a device which is configured for performing calculations or logic operations. In particular, the processor may be configured for processing basic instructions that drive the computer or system. As an example, the processor may comprise at least one arithmetic logic unit (ALU), at least one floating-point unit (FPU), such as a math co-processor or a numeric co-processor, a plurality of registers, specifically registers configured for supplying operands to the ALU and storing results of operations, and a memory, such as an L1 and L2 cache memory. In particular, the processor may be a multi-core processor. Specifically, the processor may be or may comprise a central processing unit (CPU). Additionally or alternatively, the processor may be or may comprise a microprocessor, thus specifically the processor's elements may be contained in one single integrated circuitry (IC) chip. Additionally or alternatively, the processor may be or may comprise one or more application-specific integrated circuits (ASICs) and / or one or more field-programmable gate arrays (FPGAs) and / or one or more tensor processing unit (TPU) and / or one or more chip, such as a dedicated machine learning optimized chip, or the like. The processor specifically may be configured, such as by software programming, for performing one or more operations.

[0081] The term "storing" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to at least one process of recording and / or retraining of data. The storing may comprise storing the watermarked digital content such as by using at least one database.

[0082] The term "transmitting" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to providing the watermarked digital content to at least one further device, e.g. of at least one user. The term "displaying" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to providing a visual output. The displaying may be performed by using at least one display device. The term "display device" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary device configured for receiving at least one electrical signal and providing a corresponding visual output. The display device may comprise at least one projector and / or at least one screen.

[0083] For example, the digital content may comprise at least one video. Steps a) to c) may be performed at an intermittent time interval while the video is recorded and transmitted. For example, in case of a video, 25 frames per second are typical for a video. Thus, e.g. steps a) to c) may be repeated for each 25 frames. For example, the intermittent time interval may be selected from every second, every 5, 10, 30, or 60 seconds, or an arbitrary interval selected by a user.

[0084] In a further aspect, a computer-implemented method for authentication of digital content, in particular comprising moving images, is disclosed.

[0085] The term "authentication” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to verifying the digital content, in particular that the digital content is not manipulated. Specifically, authentication may comprise distinguishing between the original digital security item and an amended digital security item.

[0086] The method comprises the following method steps, which, as an example, may be performed in the given order. However, a different order is also feasible. Further, it is possible to perform two or more of the method steps simultaneously or in a fashion overlapping in time. Further, it is also possible to perform one, more than one or even all of the method steps repeatedly.

[0087] The method comprises

[0088] A) retrieving the digital content and a timestamp of the digital content, wherein the digital content is suspected to be digital watermarked by using a method according to the present invention for digital watermarking of a digital content;

[0089] B) decoding the digital content thereby determining at least one authentication information;

[0090] C) authenticating the digital content depending on the authentication information With respect to definitions and embodiments, reference is made to the methods as described in one or more embodiments above, or as described in more detail below.

[0091] The method steps A) to C) may be performed by using at least one processor.

[0092] The term "retrieving" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process of a system, specifically a computer system, generating data and / or obtaining data from an arbitrary data source, such as from a data storage, from a network or from a further computer or computer system. The retrieving specifically may take place via at least one computer interface, such as via a port such as a serial or parallel port. The retrieving may comprise several sub-steps, such as the sub-step of obtaining one or more items of primary information and generating secondary information by making use of the primary information, such as by applying one or more algorithms to the primary information, e.g. by using a processor.

[0093] The retrieving may be performed by the trusted authority or a service provider, e.g. a service provider providing the digital content.

[0094] The method may comprise requesting authentication of digital content by a trusted authority. The method may comprise transferring a request for authentication to the trusted authority. The request may comprise the extracted digital image and / or the digital content and / or the timestamp of the digital content.

[0095] The term "decoding" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process of detecting the digital security item within the watermarked digital content and / or extracting the digital security item from the watermarked digital content. The decoding may be performed by using at least one decoder. The decoder may comprise at least one light sensor, wherein the light sensor may be sensitive at least in the wavelength range used for generating the digital security item. For example, in case of using a particle system for generating the digital security item any manipulation of the digital content can be detected by a breakdown of the continuous particle motion, which can be detected by the light sensor for the wavelengths of the moving particles.

[0096] The term "authentication information" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to information which can be used for verifying the digital content.

[0097] The method may comprise decoding the digital content thereby extracting a digital image. The authentication information may comprise a result of a comparison of the extracted digital image and a reference digital image for said timestamp. For example, the reference digital image may be the digital image of the physical and / or chemical system at that time point.

[0098] The method may comprise comparing the extracted digital image and a reference digital image for said timestamp and authenticating the digital content in case the extracted digital image corresponds to the reference digital image at least within tolerances. The digital content may be authenticated in case the extracted digital image corresponds to the reference digital image at least within tolerances. For example, the tolerances of the number of pixels matching the position of the colored pixel of the digital security item with the position of the pixel of the same color of the watermarked digital content may be of 0 to 1000000 pixels, preferably between 0 to 10000 pixels, most preferably 0 to 1000 pixels. In case this requirement is not fulfilled, the digital content is not authenticated.

[0099] The method may comprise decoding the digital content thereby extracting a digital image. The authentication information may comprise a result of a comparison of an associated timestamp of the extracted digital image and a timestamp of the digital content. The method may comprise determining an associated timestamp of the extracted digital image and authenticating the digital content if the determined associated timestamp corresponds to the timestamp of the digital content.

[0100] For example, the authentication information may comprise information about a time development of the extracted digital image. The decoding may comprise a digital filtering. For example, as outlined above, the particle system used for generating the digital security item may comprise a particle collective of red, green and blue particles and an amount of black particles with an RGB color of (0, 0, 0). The watermarked digital content may comprise a video comprising a sequence of images. The digital filtering may comprise determining pixels having a maximum color value "255” in one RGB color, e.g. (XX, YY, 255), wherein XX and YY are arbitrary values. In case the determined pixels show a particle movement which corresponds to a continuous movement, the video may be authenticated. Showing a tearing off the continuous movement (but chaotic) would hint to a manipulated video. The image position and relative position of the pixels with the maximum color value „255" it may be possible to determine the exact timestamp of recording of each image of the video sequence.

[0101] Steps B) and C) may be separate steps or may be performed within a combined decoding step. For example, the decoding may comprise analysis and comparison of the extracted digital security item with a reference digital image, i.e. the original digital image of the original digital security item. The method may comprise at least one confidence assessment comprising determining the similarity between the extracted digital image and the reference digital image. The decoding may comprise using at least one image processing algorithm.

[0102] The method may comprise performing at least one security action in case the extracted digital image is not authenticated. The security action comprises one or more of: issuing at least one warning, stopping data transfer, identification of the counterfeiter, blocking of the counterfeiter and the like. In a further aspect, a use of a digital security item generated by using a method for generating a digital security item according to the present invention for providing data security according to at least one security level is disclosed. With respect to definitions and embodiments, reference is made to the methods as described in one or more embodiments above, or as described in more detail below.

[0103] The term "security level" as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a, a level offering a defined degree of security and protection of data.

[0104] For example, the security level is basic, secure or top secure, wherein basic refers to a minimum security level, secure to a medium security level and top secure to a maximum security level.

[0105] The top secure security level may allow for protecting for manipulation of existing data content and / or against data content generated by artificial intelligence. The digital content and the digital security item may be generated at the identical location, e.g. a protected room, and may be merged at said location.

[0106] The secure security level may allow for protecting for manipulation of existing data content and / or against data content generated by artificial intelligence, but may has a risk that the digital content may be attacked bevor the watermarking. The digital content and the digital security item may be generated at the different locations and may be merged subsequently.

[0107] The basic security level may allow for protecting against manipulation of the watermarked digital content after watermarking.

[0108] Further disclosed and proposed herein is a computer program including computer-executable instructions for performing one or more of the methods according to the present invention in one or more of the embodiments enclosed herein when the program is executed on a computer or computer network. Specifically, the computer program may be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0109] As used herein, the terms "computer-readable data carrier” and "computer-readable storage medium” specifically may refer to non-transitory data storage means, such as a hardware storage medium having stored thereon computer-executable instructions. The computer-readable data carrier or storage medium specifically may be or may comprise a storage medium such as a random-access memory (RAM) and / or a read-only memory (ROM).

[0110] Thus, specifically, one, more than one or even all of method steps as indicated above may be performed by using a computer or a computer network, preferably by using a computer program. Further disclosed and proposed herein is a computer program product having program code means, in order to perform one or more of the methods according to the present invention in one or more of the embodiments enclosed herein when the program is executed on a computer or computer network. Specifically, the program code means may be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0111] Further disclosed and proposed herein is a data carrier having a data structure stored thereon, which, after loading into a computer or computer network, such as into a working memory or main memory of the computer or computer network, may execute one or more of the methods according to one or more of the embodiments disclosed herein.

[0112] Further disclosed and proposed herein is a computer program product with program code means stored on a machine-readable carrier, in order to perform one or more of the methods according to one or more of the embodiments disclosed herein, when the program is executed on a computer or computer network. As used herein, a computer program product refers to the program as a tradable product. The product may generally exist in an arbitrary format, such as in a paper format, or on a computer-readable data carrier and / or on a computer-readable storage medium. Specifically, the computer program product may be distributed over a data network.

[0113] Finally, disclosed and proposed herein is a modulated data signal which contains instructions readable by a computer system or computer network, for performing one or more of the methods according to one or more of the embodiments disclosed herein.

[0114] Referring to the computer-implemented aspects of the invention, one or more of the method steps or even all of the method steps of one or more of the methods according to one or more of the embodiments disclosed herein may be performed by using a computer or computer network. Thus, generally, any of the method steps including provision and / or manipulation of data may be performed by using a computer or computer network. Generally, these method steps may include any of the method steps, typically except for method steps requiring manual work, such as providing the samples and / or certain aspects of performing the actual measurements.

[0115] Specifically, further disclosed herein are: a computer or computer network comprising at least one processor, wherein the processor is adapted to perform one or more of the methods according to one of the embodiments described in this description, a computer loadable data structure that is adapted to perform one or more of the methods according to one of the embodiments described in this description while the data structure is being executed on a computer, a computer program, wherein the computer program is adapted to perform one or more of the methods according to one of the embodiments described in this description while the program is being executed on a computer, a computer program comprising program means for performing one or more of the methods according to one of the embodiments described in this description while the computer program is being executed on a computer or on a computer network, a computer program comprising program means according to the preceding embodiment, wherein the program means are stored on a storage medium readable to a computer, a storage medium, wherein a data structure is stored on the storage medium and wherein the data structure is adapted to perform one or more of the methods according to one of the embodiments described in this description after having been loaded into a main and / or working storage of a computer or of a computer network, and a computer program product having program code means, wherein the program code means can be stored or are stored on a storage medium, for performing one or more of the methods according to one of the embodiments described in this description, if the program code means are executed on a computer or on a computer network.

[0116] As used herein, the terms "have”, "comprise” or "include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions "A has B”, "A comprises B” and "A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0117] Further, it shall be noted that the terms "at least one”, "one or more” or similar expressions indicating that a feature or element may be present once or more than once typically are used only once when introducing the respective feature or element. In most cases, when referring to the respective feature or element, the expressions "at least one” or "one or more” are not repeated, nonwithstanding the fact that the respective feature or element may be present once or more than once.

[0118] Further, as used herein, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention. Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

[0119] Embodiment 1 . A method for generating a digital security item, wherein the method comprises the following steps

[0120] I. providing a physical and / or chemical system having a detectable, nondeterministic time behavior; ii. generating the digital security item by generating a digital image of the physical and / or chemical system at a time point by using at least one imaging device, and associating the digital image with a unique timestamp relating to the time point, wherein the digital security item comprises the generated digital image and the associated unique timestamp.

[0121] Embodiment 2. The method according to the preceding embodiment, wherein the method comprises generating a plurality of digital security items, wherein the method comprises generating the digital security items at the same frequency as a frequency of digital frames of moving images to be watermarked with the digital security items.

[0122] Embodiment 3. The method according to any one of the preceding embodiments, wherein the method comprises storing the digital image and the unique timestamp by a trusted authority, wherein steps I. and ii. are performed by the trusted authority.

[0123] Embodiment 4. The method according to the preceding embodiment, wherein the method comprises the trusted authority storing the generated digital security item in at least one database.

[0124] Embodiment 5. The method according to any one of the two preceding embodiments, wherein the method comprises the trusted authority recording the generated digital security item as a non-fungible token on a blockchain.

[0125] Embodiment 6. The method according to any one of the preceding embodiments, wherein the method comprises the trusted authority transferring the generated digital security item via at least one secure communication channel to a user or a service provider.

[0126] Embodiment 7. The method according to any one of the preceding embodiments, wherein the physical and / or chemical system comprises at least one element selected from the group consisting of: a system comprising a quantity of particles, wherein at least one subset of the quantity of particles has at least one different property than the remaining quantity of particles; a fluidic system comprising at least two fluids having different properties; a system comprising at least of one liquid and one quantity of particles having different properties; a system comprising at least of one gaseous material and one liquid having different properties; a system comprising at least of one gaseous material and a quantity of particles having different properties.

[0127] Embodiment 8. The method according to any one of the preceding embodiments, wherein the physical and / or chemical system comprises a system comprising a quantity of particles, wherein the quantity of particles comprises a mixture of particles of at least two particle subsets having different properties, a bulk of particles of at least two particle subsets having different properties.

[0128] Embodiment 9. The method according to the preceding embodiment, wherein a particle size is from 0.1 m to 0.0001 m, preferably between 1 mm and 0,1 pm.

[0129] Embodiment 10. The method according to any one of the preceding embodiments, wherein the detectable, non- deterministic time behavior is one or more of optically detectable, magnetically detectable, electrically detectable, electro-statically detectable.

[0130] Embodiment 11 . The method according to any one of the two preceding embodiments, wherein the optical property is at least one property selected from the group consisting of: diameter, shape, color, density, flowability, magnetism, hydrophilicity, ionic and atomic radiation.

[0131] Embodiment 12. The method according to any one of the three preceding embodiments, wherein the system comprises a quantity of particles, wherein the quantity of particles comprises a subset of black particles and a subset of at least one color particles.

[0132] Embodiment 13. The method according to any one of the preceding embodiments, wherein step ii. comprises imaging the physical and / or chemical system by using at least one color-camera.

[0133] Embodiment 14. The method according to any one of the preceding embodiments, wherein the digital image comprises one or more of: a 2D image, a 3D image, a 2D video, a 3D video, content generated by using a tomographic technique.

[0134] Embodiment 15. The method according to any one of the preceding embodiments, wherein the method comprises applying at least one physical and / or chemical influence on the physical and / or chemical system thereby detectable changing the state of the physical and / or chemical system, wherein the influence comprises one or more of shaking, mixing, stirring, vibrating, applying gas flow, changing of a magnetic field, applying an electro-magnetic influence such as applying microwaves. Embodiment 16. The method according to any one of the preceding embodiments, wherein the method comprises repeating steps i. and ii. and at different time points.

[0135] Embodiment 17. The method according to the preceding embodiment, wherein the method comprises recording a plurality of video frames, wherein the timestamp is recorded for each frame or a pre-defined intermittent time interval.

[0136] Embodiment 18. A computer-implemented method for digital watermarking of a digital content, in particular comprising moving images, wherein the method comprises a) providing the digital content; b) merging the digital content with a digital image of at least one digital security item generated by using a method for generating a digital security item according to any one of the preceding embodiments thereby generating watermarked digital content; and c) one or more of storing, transmitting, or displaying the displaying the watermarked digital content.

[0137] Embodiment 19. The method according to the preceding embodiment, wherein the digital content comprises one or more of: a 2D image, a 3D image, a 2D video, a 3D video, content generated by using a tomographic technique.

[0138] Embodiment 20. The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein the digital content comprises at least one video, wherein steps a) to c) are performed at an intermittent time interval while the video is recorded and transmitted.

[0139] Embodiment 21 . The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein the merging comprises adding of pixel color values of pixels of the digital content and pixel color values of the pixels of the digital image of the digital security item.

[0140] Embodiment 22. The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein an image resolution of the digital image of the digital security item is selected to correspond to the image resolution of the digital content.

[0141] Embodiment 23. The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein the method comprises hidden watermarking, wherein a wavelength content of the digital image of the digital security item is selected such that a difference between the digital content before merging and after merged is outside the range of perception of the human eye. Embodiment 24. The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein the complete digital content is merged with the digital image of the digital security item or wherein at least one part of the digital content is merged with the digital image of the digital security item.

[0142] Embodiment 25. The method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content, wherein the method comprises detecting a face in the digital content by using at least one face detection algorithm, wherein at least one part of the digital content comprising the detected face is merged with the digital image of the digital security item.

[0143] Embodiment 26. A computer-implemented method for authentication of digital content, in particular comprising moving images, wherein the method comprises

[0144] A) retrieving digital content and a timestamp of the digital content, wherein the digital content is suspected to be digital watermarked by using a method according to the present invention or digital watermarking of a digital content;

[0145] B) decoding the digital content thereby determining at least one authentication information;

[0146] C) authenticating the digital content depending on the authentication information.

[0147] Embodiment 27. The method according to the preceding embodiment, wherein the method comprises requesting authentication of digital content by a trusted authority, wherein the method comprises transferring a request for authentication to the trusted authority, wherein the request comprises the extracted digital image and / or the digital content and / or the timestamp of the digital content.

[0148] Embodiment 28. The method according to any one of the preceding embodiments referring to a method for authentication, wherein the decoding comprises using at least one image processing algorithm.

[0149] Embodiment 29. The method according to any one of the preceding embodiments referring to a method for authentication, wherein the method comprises performing at least one security action in case the extracted digital image is not authenticated, wherein the security action comprises one or more of: issuing at least one warning, stopping data transfer, identification of the counterfeiter, blocking of the counterfeiter and the like.

[0150] Embodiment 30. Use of a digital security item generated by using a method for generating a digital security item according to any one of the preceding embodiments referring to a method for generating a digital security item for providing data security according to at least one security level. Embodiment 31 . A digital security item, wherein the digital security item is generated by using a method for generating a digital security item according to any one of the preceding embodiments referring to a method for generating a digital security item.

[0151] Embodiment 32. A computer program comprising instructions which, when the program is executed by a processing device, cause the processing device to perform a method for generating a digital security item according to any one of the preceding embodiments referring to a method for generating a digital security item and / or a computer-implemented method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

[0152] Embodiment 33. A computer-readable storage medium comprising instructions which, when the instructions are executed by the processing device, cause the processing device to perform a method for generating a digital security item according to any one of the preceding embodiments referring to a method for generating a digital security item and / or a computer-implemented method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

[0153] Embodiment 34. A non-transient computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to perform a method for generating a digital security item according to any one of the preceding embodiments referring to a method for generating a digital security item and / or a computer-implemented method according to any one of the preceding embodiments referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

[0154] Short description of the Figures

[0155] Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0156] In the Figures:

[0157] Figure 1 shows an embodiment of a computer-implemented method for digital watermarking of a digital content and a method for authentication of digital content; and Figure 2 shows an embodiment of a method for generating of a digital security item using a (2-dim) fluidized bed.

[0158] Detailed description of the embodiments

[0159] Figure 1 shows an embodiment of a computer-implemented method for digital watermarking of a digital content 110 and a method for authentication of digital content.

[0160] In the embodiment of Figure 1, the method for digital watermarking comprises a) (112) providing the digital content 110; b) (114) merging the digital content 110 with a digital image 116 of at least one digital security item 126 generated (indicated by reference number 118) by using a method for generating a digital security item 126 according to the present invention thereby generating watermarked digital content 114; and c) (120) one or more of storing, transmitting, or displaying the watermarked digital content 122. In the embodiment of Figure 1, the watermarked digital content 122 is displayed.

[0161] The digital content 110 may comprise in this embodiment a frame of a video. In this embodiment, the frame of the video may comprise a moving sketched man. The digital content 110 may be generated by recording a video using at least one camera. The digital content 110 may comprise color pixels, wherein different colors are shown here as different greyscale values. The digital content 110 comprises a timestamp, e.g. comprising a date and time. The timestamp may be a time information provided by the camera used for recording the video. In this embodiment the timestamp of the digital content 110 is "2021-01-01 00:00:00”. Two exemplary pixels are highlighted, e.g. a pink pixel with color values (240, 130, 240) and an orange pixel with color values (240, 210, 40).

[0162] As further shown in Figure 1, the digital security item 126 may comprise the digital image 116 having at corresponding image positions (i.e. at the image positions of the pink and the orange pixel) green pixels with color values (0, 255, 0). The quantity of particles used for generating the digital security item 126 may comprise from 70% to 99 % black particles, preferably more than 90% black particles. The quantity of particles for the embodiment of Figure 1, may be selected such that the digital image of the physical and / or chemical system has two green pixels and all other pixels are black (0, 0, 0).

[0163] The digital image 116 may be generated by using a setup as shown in Figure 2, which will be described in more detail below. The digital image 116 may have a unique timestamp t1 , e.g. comprising a date and time. In this embodiment the timestamp of the digital image 116 is "2021-01-01 00:00:00”.

[0164] The color values of the pixels of the digital security item 126 may be added to the color values of the corresponding pixels of the digital content 110, thereby generating a watermarked digital content 122. By merging with the pixels of the digital security item, the color value of the pixels of the digital content 110 may get a maximum color portion of 255. For example, if a pixel of the digital security item 126 having a color value of blue (0, 0, 255) is merged with a pixel of the digital content having a color value of green (0, 100, 0), the final pixel of the watermarked digital content may have the color value (0, 100, 255). In Figure 1 , the merging 114 may comprise pixelwise addition. Each color value of > 255 is set to 255. As shown in Figure 1 , the pink pixel and the orange pixel of the original digital content have changed into light green (240, 255, 240) and yellow (240, 255, 40).

[0165] Figure 1 further shows authentication of the watermarked digital content 124, in particular a forgery check.

[0166] The method comprises

[0167] A) retrieving digital content 124 and a timestamp of the digital content 124, wherein the digital content 124 is suspected to be digital watermarked by using a method according to the present invention for digital watermarking of a digital content;

[0168] B) decoding the digital content 124 thereby determining at least one authentication information;

[0169] C) authenticating the digital content 124 depending on the authentication information.

[0170] The method may comprise decoding the digital content 124 thereby extracting a digital image. The method may comprise comparing the extracted digital image and a reference digital image for said timestamp, e.g. the reference digital image may be the digital image 116 of the physical and / or chemical system at that time point. In this embodiment, the timestamp may be t1 .

[0171] The decoding may comprise digital filtering. In this specific embodiment of a digital security item 126 with green pixels with color values (0, 255, 0), the authentication may comprise determining if the "GG value” of the color values (RR, GG, BB) of the corresponding pixels in the digital content 124' is 255.

[0172] Figure 1 shows two examples of digital content. On the upper left, the value 255 can be found in the corresponding pixels of the digital content 124 and the digital content 124 can be authenticated (indicated by a hook). In the lower part, values different from 255 for GG are present such that this digital content 124 is not authenticated (indicated by a cross).

[0173] Figure 2 shows an exemplary setup for performing a method for generating a digital security item 126 according to the present invention, in front view on the left side and in side view on the right side of Figure 2. In this embodiment, a physical and / or chemical system 128 may be used which comprises a fluidized bed within a chamber. The physical and / or chemical system 128 comprises in this embodiment moving particles 140, e.g. a quantity of black particles 142 and color particles 144, e.g. green particles. In Figure 2, black particles are depicted as smaller points and green as bigger points within the chamber. As outlined above, the quantity of particles may comprise more than 90% black particles. For example, as depicted in Figure 2, within the digital image recorded by a video camera 138, only 7 particles out of the particle quantity may be green and all others may be black. This can allow changing only a few pixels, i.e. the pixels of the digital content to which the pixels of the green particles are added, when watermarking with the digital security item.

[0174] The particles may be moving within the chamber, e.g. by applying a gas flow, in particular air, via at least one distribution system 130 comprising at least one gas inlet 132, a plurality of nozzles 134 and at least one gas outlet 136. Other influences may be possible, too. The gas flow may be applied once or at different time points or continuously.

[0175] The particle movement within the chamber may be recorded by using at least one imaging device, e.g. a video camera 138. An exemplary 16:9 frame of the video camera is depicted. The imaging device may be configured for providing a time of recording the video which can be used as timestamp.

[0176] The method may comprise generating the digital security item 126 by generating a digital image 116, in particular a video frame of the recorded particle movement, of the physical and / or chemical system 128 at a time point by using the imaging device, and associating the digital image 116 with a unique timestamp relating to the time point. The digital security item 126 comprises the generated digital image 116 and the associated unique timestamp.

[0177] List of reference numbers digital content providing digital content merging the digital content digital image generated digital security item displaying watermarked digital content digital content digital security item physical and / or chemical system distribution system gas inlet nozzles gas outlet video camera moving particles black particles color particles

Claims

Claims1 . A method for generating a digital security item (126), wherein the method comprises the following stepsI. providing a physical and / or chemical system (128) having a detectable, nondeterministic time behavior; ii. generating the digital security item (126) by generating a digital image (116) of the physical and / or chemical system (128) at a time point by using at least one imaging device, and associating the digital image (116) with a unique timestamp relating to the time point, wherein the digital security item (126) comprises the generated digital image (116) and the associated unique timestamp.

2. The method according to the preceding claim, wherein the method comprises generating a plurality of digital security items, wherein the method comprises generating the digital security items at the same frequency as a frequency of digital frames of moving images to be watermarked with the digital security items.

3. The method according to any one of the preceding claims, wherein the method comprises storing the digital image and the unique timestamp by a trusted authority, wherein steps I. and ii. are performed by the trusted authority.

4. The method according to any one of the preceding claims, wherein the physical and / or chemical system (128) comprises a system comprising a quantity of particles, wherein the quantity of particles comprises a mixture of particles of at least two particle subsets having different optical properties, a bulk of particles of at least two particle subsets having different optical properties, wherein a particle size is from 0.1 m to 0.001 pm.

5. The method according to any one of the preceding claims, wherein the detectable, nondeterministic time behavior is one or more of optically detectable, magnetically detectable, electrically detectable, electro-statically detectable.

6. The method according to any one of the two preceding claims, wherein the optical property is at least one property selected from the group consisting of: diameter, shape, color, density, flowability, magnetism, hydrophilicity, ionic and atomic radiation.

7. The method according to any one of the three preceding claims, wherein the system comprises a quantity of particles, wherein the quantity of particles comprises a subset of black particles and a subset of color particles.

8. The method according to any one of the preceding claims, wherein the method comprises applying at least one physical and / or chemical influence on the physical and / or chemical system (128) thereby detectable changing the state of the physical and / or chemical system, wherein the influence comprises one or more of shaking, mixing, stirring, vibrating, applying gas flow, changing of a magnetic field, applying an electro-magnetic influence.

9. A computer-implemented method for digital watermarking of a digital content (110), in particular comprising moving images, wherein the method comprises a) (112) providing the digital content (110); b) (114) merging the digital content (110) with a digital image (116) of at least one digital security item (126) generated by using a method for generating a digital security item according to any one of the preceding claims thereby generating watermarked digital content (122); and c) (120) one or more of storing, transmitting, or displaying the displaying the watermarked digital content (122).

10. The method according to the preceding claim, wherein the merging comprises adding of pixel color values of pixels of the digital content (124) and pixel color values of the pixels of the digital image (116) of the digital security item (126).11 . The method according to any one of the preceding claims referring to a method for digital watermarking of a digital content, wherein the method comprises hidden watermarking, wherein a wavelength content of the digital image (116) of the digital security item (126) is selected such that a difference between the digital content before merging and after merged is outside the range of perception of the human eye.

12. The method according to any one of the preceding claims referring to a method for digital watermarking of a digital content, wherein the complete digital content is merged with the digital image (116) of the digital security item (126) or wherein at least one part of the digital content is merged with the digital image (116) of the digital security item (126).

13. The method according to any one of the preceding claims referring to a method for digital watermarking of a digital content, wherein the method comprises detecting a face in the digital content by using at least one face detection algorithm, wherein at least one part of the digital content comprising the detected face is merged with the digital image (116) of the digital security item (126).

14. A computer-implemented method for authentication of digital content (124), in particular comprising moving images, wherein the method comprisesA) retrieving the digital content and a timestamp of the digital content (124), wherein the digital content (124) is suspected to be digital watermarked by using a method according to any one of the preceding claims referring to a method for digital watermarking of a digital content;B) decoding the digital content (124) thereby determining at least one authentication information;C) authenticating the digital content (124) depending on the authentication information.

15. The method according to the preceding claim, wherein the method comprises requesting authentication of digital content by a trusted authority, wherein the method comprises transferring a request for authentication to the trusted authority, wherein the request comprises the extracted digital image and / or the digital content and / or the timestamp of the digital content.

16. Use of a digital security item generated by using a method for generating a digital security item according to any one of the preceding claims referring to a method for generating a digital security item for providing data security according to at least one security level.

17. A digital security item (126), wherein the digital security item (126) is generated by using a method for generating a digital security item according to any one of the preceding claims referring to a method for generating a digital security item.

18. A computer program comprising instructions which, when the program is executed by a processing device, cause the processing device to perform a method for generating a digital security item according to any one of the preceding claims referring to a method for generating a digital security item and / or a computer-implemented method according to any one of the preceding claims referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

19. A computer-readable storage medium comprising instructions which, when the instructions are executed by the processing device, cause the processing device to perform a method for generating a digital security item according to any one of the preceding claims referring to a method for generating a digital security item and / or a computer-implemented method according to any one of the preceding claims referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

20. A non-transient computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to perform a method for generating a digital security item according to any one of the preceding claims referring to a method for generating a digital security item and / or a computer- implemented method according to any one of the preceding claims referring to a method for digital watermarking of a digital content and / or computer-implemented method for authentication of digital content.

Images