EP4626630A1

EP4626630A1 - Method and apparatus providing evidence of ownership for a 3d printed object

Info

Publication number: EP4626630A1
Application number: EP22968673.8A
Authority: EP
Inventors: Tommy Arngren; Alexander Hunt; Dmitry KNYAGININ; Bernard Smeets
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2025-10-08
Also published as: WO2024128944A1; EP4626630A4

Abstract

A method (100) for providing evidence of ownership of a three-dimensional, 3D, printed object (500) having an identification mark (501). The method comprises obtaining (101) a first set of sensor data, associated to an identity of a first owner of the 3D printed object, where the first set of sensor data is acquired using one or more first sensors (306). The method further comprises obtaining (102) a second set of sensor data, where the second set of sensor data is acquired using a selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors (307). The method further comprises creating (103) a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data. Moreover, there is a related method, apparatuses, computer programs, and computer program products.

Description

METHOD AND APPARATUS PROVIDING EVIDENCE OF OWNERSHIP FOR A 3D PRINTED OBJECT

TECHNICAL FIELD

The present invention relates to methods and apparatuses for providing evidence of ownership of a 3D printed object. A related verification server, network node, 3D printer, UE, computer program, and computer program product are also disclosed.

BACKGROUND

Provenance is the chronology of ownership, custody, or location of an object. The term was originally primarily used in relation to works of art, but may now be used in a similar sense for a wide range of fields, including archaeology, paleontology, archives, manuscripts, printed books, the circular economy, science, and computing.

There are many forms of provenance documentation. A signed statement from the artist of a piece of art, or an assessment by an expert on the artist may be a start of a provenance document for a piece of art. The provenance document may further comprise a first sales receipt, and receipts of subsequent transfers of ownership of the object through for example sales, gift letters, and wills. Unfortunately, such provenance documents can be forged, either in their entirety, or a specific item may be forged and the provenance document attached to a different, forged piece of art.

For objects manufactured wholly or partly in batches, there are other methods for ensuring uniqueness and authenticity. For example, an individual item may be marked by a serial number, or the item may be manufactured using methods and materials which are difficult to replicate. In other scenarios, an object may be identified as part of a larger batch of items, where all objects in the same batch share some properties which may differ from another batch.

In the context of additive manufacturing, such as home 3D printing of an object, it is extremely difficult to prove the provenance of any physical object. The same source file may be used to produce any number of copies of the 3D printed object, which are identical up to variations between the 3D printers used to create the 3D printed objects. Therefore, providing evidence that a particular 3D printed object belongs to a specific batch of objects or is the unique first one (which may be desired in cases of works of art) may be difficult. In prior art, there have been some attempts to create a provenance for a 3D printed object. For example, US 20200273048 A1 discloses a system and method for provisioning cryptographic digital assets for blockchain-secured retail products. The disclosure attempts to link a digital asset to a physical asset, but fails to uniquely link a digital asset to a specific instance of a physical asset - rather, it links a digital asset to any similar physical asset.

The article “Provenance in the Additive Manufacturing Process” by N. F. Fadhel, R. M. Crowder, and G. B. Wills, 2015, IFAC-PapersOnLine, 48(3), 2345-2350 provides an overview of methods which may be used to track provenance of a 3D printed object. However, the disclosed methods fail to connect a specific object to a specific person - the owner of the object.

SUMMARY

An object of the invention is to provide evidence of ownership of a 3D printed object.

According to a first aspect of the invention, there is a method for providing evidence of ownership of a three-dimensional, 3D, printed object having an identification mark. The method comprises obtaining a first set of sensor data, associated to an identity of a first owner of the 3D printed object, the first set of sensor data being acquired using one or more first sensors. The method further comprises obtaining a second set of sensor data, the second set of sensor data being acquired using a selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors. The method further comprises creating a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data.

According to an embodiment of the first aspect, the method further comprises receiving a digital file of the 3D printed object and instructing a 3D printer to print the 3D printed object with the identification mark.

According to an embodiment of the first aspect the method further comprises instructing the one or more first sensors to record the first set of sensor data.

According to an embodiment of the first aspect the method further comprises storing the provenance document. According to an embodiment of the first aspect storing the provenance document comprises securing the provenance document.

According to an embodiment of the first aspect, securing the provenance document comprises adding the provenance document to a blockchain.

According to an embodiment of the first aspect, securing the provenance document comprises adding a hash value of the provenance document to a blockchain.

According to an embodiment of the first the first set of sensor data comprises sensor data which provide evidence of the identity of the first owner of the 3D printed object.

According to an embodiment of the first aspect, the first set of sensor data comprises sensor data which provide evidence of a location connected to the first owner where the 3D object was manufactured.

According to an embodiment of the first aspect, the first set of sensor data comprises sensor data which provide evidence of a time connected to the first owner when the 3D object was manufactured.

According to an embodiment of the first aspect, the method further comprises providing the 3D printed object with the identification mark.

According to an embodiment of the first aspect, the identification mark comprises a pseudorandom mark inserted into the 3D printed object during the production of the 3D printed object.

According to an embodiment of the first aspect, the method further comprises selecting a sensing technique to sense the identification mark of the 3D printed object.

According to an embodiment of the first aspect, the selected sensing technique for acquiring the second set of sensor data depends on the properties of the identification mark.

According to an embodiment of the first aspect selecting the sensing technique comprises selecting environmental conditions for acquiring the second set of sensor data. According to an embodiment of the first aspect selecting the sensing technique comprises selecting second sensor settings for the one or more second sensors used to acquire the second set of sensor data.

According to an embodiment of the first aspect obtaining the second set of sensor data comprises obtaining a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data.

According to an embodiment of the first aspect obtaining a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data includes obtaining measurement result using the selected sensing technique and the one or more second sensors in which the selected second sensor settings have been set up.

According to an embodiment of the first aspect, obtaining the second set of sensor data comprises obtaining a result of a simulation of a behavior of the one or more second sensors according to the selected sensing technique so as to calculate an expected set of sensor data, wherein the second set of sensor data comprises the expected sensor data.

According to an embodiment of the first aspect, obtaining the second set of sensor data is performed after the 3D printed object is completed.

According to an embodiment of the first aspect, obtaining the second set of sensor data is performed during the production of the 3D printed object.

According to an embodiment of the first aspect, the method further comprises receiving an updated first set of sensor data in the provenance document to comprise a third set of sensor data related to an identity of a second owner.

According to a second aspect of the invention, there is a method for providing evidence of ownership of a three-dimensional, 3D, printed object. The method comprises obtaining a provenance document comprising a first set of sensor data, an indication of a sensing technique, and a second set of sensor data. The first set of sensor data is associated to an identity of a first owner of the 3D printed object, and is acquired using one or more first sensors, and the second set of sensor data is obtained using the selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors having selected second sensor settings. The method further comprises providing a requester with a one-time key, wherein information included in the one-time key is used to define a one-time second sensor setting for one or more of the second sensors. The method further comprises calculating a fourth set of sensor data as a function of the second set of sensor data and the one-time second sensor setting. The method further comprises receiving a sixth set of sensor data, obtained by sensing the identification mark using the selected sensing technique and the one or more second sensors, the one or more second sensor having the selected second sensor settings, wherein one of the selected second sensor settings has been replaced with the one-time second sensor setting. The method further comprises comparing the fourth set of sensor data to the sixth set of sensor data.

According to an embodiment of the second aspect providing a requester with a onetime key is performed only if the requester has an identity matching the identity of the first owner as identified by the first set of sensor data.

According to an embodiment of the second aspect the method further comprises receiving a fifth set of sensor data, the fifth set of sensor data comprising information relative to the identity of the requester.

According to an embodiment of the second aspect the method further comprises comparing the fifth set of sensor data to the first set of sensor data.

According to an embodiment of the second aspect, comparing the fifth set of sensor data to the first set of sensor data comprises calculating a first measure of similarity between the fifth set of sensor data and the first set of sensor data and comparing the first measure of similarity to a first threshold value.

According to an embodiment of the second aspect providing a one-time key is performed only if a request for the one-time key is received and the request is signed by a private key belonging to the first owner of the 3D printed object.

According to an embodiment of the second aspect comparing the fourth set of sensor data to the sixth set of sensor data comprises determining a second measure of similarity between the sixth set of sensor data and the fourth set of sensor data. According to an embodiment of the second aspect comparing the fourth set of sensor data to the sixth set of sensor data comprises comparing the second measure of similarity to a second threshold value.

According to an embodiment of the second aspect the method further comprises confirming ownership of the 3D printed object by the requester if the second measure of similarity is above the second threshold value.

According to an embodiment of the second aspect the method further comprises rejecting ownership of the 3D printed object by the requester if the second measure of similarity is below the second threshold value.

According to a third aspect of the invention, there is a first apparatus for providing evidence of ownership of a three-dimensional, 3D, printed object having an identification mark. The first apparatus is configured to obtain a first set of sensor data, associated to an identity of a first owner of the 3D printed object, using one or more first sensors. The first apparatus is further configured to obtain a second set of sensor data using a selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors (307). The first apparatus is further configured to create a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data.

According to an embodiment of the third aspect the first apparatus is further configured to receive a digital file of the 3D object and instruct a 3D printer to print the 3D printed object with the identification mark.

According to an embodiment of the third aspect the first apparatus is further configured to instruct the first set of sensors to record the first set of sensor data.

According to an embodiment of the third aspect the first apparatus is further configured to storing the provenance document.

According to an embodiment of the third aspect storing the provenance document further comprises securing the provenance document.

According to an embodiment of the third aspect securing the provenance document comprises adding the provenance document to a blockchain. According to an embodiment of the third aspect securing the provenance document comprises adding a hash value of the provenance document to a blockchain.

According to an embodiment of the third aspect, the first apparatus is further configured to provide the 3D printed object with the identification mark.

According to an embodiment of the third aspect the identification mark comprises a pseudorandom mark inserted into the 3D printed object during the production of the 3D printed object.

According to an embodiment of the third aspect the first apparatus is further configured to select a sensing technique to sense the identification mark of the 3D printed object.

According to an embodiment of the third aspect select a sensing technique comprises selecting environmental conditions for acquiring the second set of sensor data.

According to an embodiment of the third aspect select the sensing technique comprises selecting second sensor settings for the one or more second sensors used to acquire the second set of sensor data.

According to an embodiment of the third aspect obtain the second set of sensor data comprises obtaining a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data.

According to an embodiment of the third aspect obtain a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data includes obtaining a measurement result using the selected sensing technique and the one or more second sensors in which the selected second sensor settings have been set up.

According to an embodiment of the third aspect obtain the second set of sensor data comprises obtaining a result of a simulation of a behavior of the one or more second sensors according to the selected sensing technique so as to calculate an expected set of sensor data, wherein the second set of sensor data comprises the expected sensor data. According to an embodiment of the third aspect the first apparatus is further configured to receive an updated first set of sensor data and adding the updated first set of sensor data to the provenance document to comprise a third set of sensor data related to an identity of a second owner.

According to a fourth aspect of the invention, there is a second apparatus for providing evidence of ownership of a three-dimensional, 3D, printed object. The second apparatus is configured to obtain a provenance document comprising a first set of sensor data, an indication of a sensing technique, and a second set of sensor data, wherein the first set of sensor data is associated to an identity of a first owner of the 3D printed object, using one or more first sensors, and the second set of sensor data is obtained using the selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors having selected second sensor settings. The second apparatus is further configured to provide a requester with a one-time key, wherein information included in the onetime key is used to define a one-time second sensor setting of the one or more second sensors. The second apparatus is further configured to calculate a fourth set of sensor data as a function of the second set of sensor data and the one-time second sensor setting. The second apparatus is further configured to receive a sixth set of sensor data, obtained by sensing the identification mark using the selected sensing technique and the one or more second sensors, the one or more second sensors having the selected second sensor settings, wherein one of the selected second sensor settings has been replaced with the one-time setting. The second apparatus is further configured to compare the fourth set of sensor data to the sixth set of sensor data.

According to an embodiment of the fourth aspect, providing a requester with a onetime key is performed only if the requester has an identity matching the identity of the first owner as identified by the first set of sensor data.

According to an embodiment of the fourth aspect, the second apparatus is further configured to receive a fifth set of sensor data, the fifth set of sensor data comprising information relative to the identity of the requester.

According to an embodiment of the fourth aspect the second apparatus is further configured to compare the fifth set of sensor data to the first set of sensor data. According to an embodiment of the fourth aspect, comparing the fifth set of sensor data to the first set of sensor data comprises calculating a first measure of similarity between the fifth set of sensor data and the first set of sensor data and comparing the first measure of similarity to a first threshold value.

According to an embodiment of the fourth aspect, provide a one-time key is performed only if a request for the one-time key is received and the request is signed by a private key belonging to the first owner of the 3D printed object.

According to an embodiment of the fourth aspect, compare the fourth set of sensor data to the sixth set of sensor data comprises determining a second measure of similarity between the sixth set of sensor data and the fourth set of sensor data.

According to an embodiment of the fourth aspect, comparing the fourth set of sensor data to the sixth set of sensor data comprises comparing the second measure of similarity to a second threshold value.

According to an embodiment of the fourth aspect, the second apparatus is configured to confirm ownership of the 3D printed object by the requester if the second measure of similarity is above the second threshold value.

According to an embodiment of the fourth aspect, the second apparatus is configured to reject ownership of the 3D printed object by the requester if the second measure of similarity is below the second threshold value.

According to a fifth aspect of the invention, there is a computer program, comprising instructions which when run on a processor belonging to an apparatus according to the third aspect, causes the apparatus to perform a method according to any embodiment of the first aspect.

According to a sixth aspect of the invention, there is a computer program product comprising a computer readable storage medium on which a computer program according to the fifth aspect is stored.

According to a seventh aspect of the invention, there is a computer program, comprising instructions which when run on a processor belonging to an apparatus according to the fourth aspect, causes the apparatus to perform a method according to any embodiment of the second aspect. According to an eighth aspect of the invention, there is a computer program product comprising a computer readable storage medium on which a computer program according to the seventh aspect is stored.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1a is a flowchart of an embodiment of a method according to the invention.

Fig. 1 b is a flowchart of a section of an embodiment of a method according to the invention in Fig. 1a.

Fig. 2a is a flowchart of an additional embodiment of a method according to the invention.

Fig. 2b is a flowchart of a section of an embodiment of a method according to the invention in Fig. 2a.

Fig. 3 is an exemplary apparatus according to an embodiment the invention.

Fig. 4 is an exemplary apparatus according to another embodiment the invention.

Fig. 5 is an exemplary 3D printed object according to the invention.

Fig. 6 is an exemplary 3D printer according to the invention.

Fig. 7 is an exemplary flow of communications according to an embodiment of the invention.

Fig. 8 is an exemplary flow of communication according to an additional embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Fig. 1a is a flowchart depicting the operations of a method 100 to provide evidence of ownership of a three-dimensional, 3D, printed object 500 (Fig. 5).

Additive manufacturing is a production process whereby an object is manufactured by iteratively adding more material until a desired product is achieved. This contrasts to a more commonly used subtractive manufacturing, where an object is manufactured by successively removing material from a larger piece of material until the desired product is achieved.

3D printing is a process of constructing a 3D object from a digital 3D model, where the 3D model is typically constructed using computer-aided design, CAD, tools. The construction process may comprise a variety of processes in which material is deposited, joined, or solidified under computer control. The material may comprise for example polymers, metals, or ceramics, alone or in combination. The material may be deposited layer-by-layer by a 3D printer. In some 3D printing processes, such as stereolithography and two-photon absorption 3D photopolymerization, the material may need to be hardened, for example by a polymerization process, after depositing each layer, or after depositing some number of layers. The hardening process may be performed for example by laser light, ultraviolet light, or another source of visible or non-visible light. In other 3D printing processes, the hardening process may be caused by applying heat, or by chemical means such as by adding a substance like epoxy, or by exposing the 3D printed object to a gas such as air.

A 3D printed object is an object obtained by a 3D printing process.

In some 3D printing processes, the 3D printed object may be obtained through a process combining additive manufacturing and subtractive manufacturing. In these manufacturing processes, the 3D printed object is first constructed slightly larger than the target and then excess material is removed, using for example mechanical means or chemical means, to achieve the final product. This combined method may be advantageous in situations where the available 3D printer has a lower accuracy than what is desired in the finished 3D printed object. In any case, the present method of the invention is applicable to any 3D printing process and it is not limited by it. Thus, any 3D printing process can be used to create the 3D printed object.

For the purpose of this disclosure, ownership refers to the state or fact of possession and/or control over property. In embodiments of this disclosure, the property is the 3D printed object. Ownership of a physical object may be held by a single individual, or jointly by a group of individuals, or by one or several juridical persons such as corporations. Ownership of a physical object may be transferred between individuals, or between groups of individuals, or between juridical persons. This disclosure will primarily focus on ownership by a single individual and transfer of ownership from a first individual to a second individual, but it will be evident to the skilled person that the disclosed method and apparatus may be adapted to situations of joint ownership by individuals or ownership by juridical persons.

Cryptographic methods may be used to partially solve ownership problems. For example, a digital document signed by a private key belonging to a specific individual provides evidence of ownership by that specific individual. For physical objects, physical signatures may play a similar role to provide evidence of ownership, sometimes in combination with provenance documents attempting to trace the history of a specific object to provide evidence of ownership. 3D printing enables a connection between a digital document, namely the plan (project) for the 3D printed object, and the physical 3D printed object. Hence, there is the option to exploit digital cryptographic techniques to provide evidence of ownership of the physical object.

For the purpose of this disclosure, evidence of ownership refers to facts which support or do not support the proposition that a particular individual is the owner of a particular 3D printed object.

The method 100 is a method for providing evidence of ownership of a 3D printed object 500, the object having an identification mark 501. In some embodiments of the invention, the identification mark is added during the 3D printing process. In other embodiments of the invention, the identification mark is added by subtractive and/or additive manufacturing after the 3D printing process is completed. The skilled person will appreciate that the properties of the identification mark may influence at which step of the manufacturing process the identification mark is added to the 3D printed object.

The identification mark may take different forms and/or be of different types. It is to be understood that the identification mark can also be a combination of one or more of the forms/types described herein below. In some embodiments, the identification mark is a non-homogeneity in the 3D printed object. In embodiments, the identification mark may take the form of negative space (e.g., a hollow cavity) within the 3D printed object. In embodiments, the identification mark may comprise a three- dimensional quick response, QR, code, or another 2D or 3D pattern.

In embodiments, the identification mark may comprise an inclusion of a material different from the material in which the majority of the 3D printed object is formed. In embodiments, this inclusion may comprise a material which exhibits a measurably different characteristic when sensed by a sensor than the material in which the majority of the 3D printed object is formed. In an embodiment, the identification mark may be visible under irradiation. For example, the identification mark may be detected by an x-ray of the 3D printed object because the x-ray radiation is differently absorbed by the identification mark and the surrounding material. The identification mark may be fluorescent and thus it may be detected (due to the visible “glow”) when irradiated by electromagnetic radiation at the proper wavelength. The identification mark may have a measurably different electrical conductivity than the material in which the majority of the 3D printed object is formed and thus the identification mark may be detected by passing an electrical current through the object. The identification mark may have measurably different magnetic properties (ferromagnetic, paramagnetic, diamagnetic, or antiferromagnetic) than the material in which the majority of the 3D printed object is formed and thus the identification mark may be detected by applying a magnetic field to the 3D printed object. The identification mark may have a measurably different electric polarizability or magnetic polarizability than the material in which the majority of the 3D printed object is formed and thus the identification mark may be detected by subjecting the 3d printed object to an electric or magnetic field and measuring the acquired electric dipole or magnetic dipole moment. The identification mark might reflect the light differently depending on the direction of light impingement. Therefore, the identification mark may reflect light differently depending on its orientation with respect to a light source.

In some embodiments, the identification mark may comprise a pseudorandom mark, that is, a mark which is statistically random but is produced by a deterministic process, inserted into the 3D printed object during the manufacturing process. The pseudorandom mark may be an inclusion as detailed above.

The pseudorandom mark may be uniquely linked to a 3D printer used to manufacture the 3D printed object. The manufacturing process of the 3D object comprises providing a 3D printer 600 (shown in Fig. 6) and supplying 105 the 3D printer with an image file format file (e.g., a computer aided design - CAD - file, such as an STL file) comprising a digital model of the 3D printed object. The 3D manufacturing process then comprises feeding the model of the 3D printed object into a piece of software called a slicer which slices the model into slices, for example parallel slices, the thickness of which depends on the desired accuracy of the finished model, the limitations of the physical printer and material used to create the 3D printed object. Each slice is then sent to the 3D printer which deposits each layer of material sequentially to produce the final 3D printed object. The identification mark in the form of a pseudorandom mark may be inserted into the model of the 3D printed object before the slicing of the model in preparation for the manufacturing of the physical 3D printed object. For example, the identification mark is incorporated in the image format file containing the 3D model. An individual with access to the device performing the slicing may be able to determine the exact form of the identification mark, since the process for inserting it may be pseudorandom, but to the outside observer the pseudorandom mark may appear to be random.

The method 100 comprises obtaining 101 a first set of sensor data using one or more first sensors, where the first set of sensor data are related to an identity of a first owner of a 3D printed object. The one or more first sensors may comprise any sensor capable of recording information sufficient to determine the identity of the first owner of the 3D printed object. Obtaining the first set of sensor data using the one or more first sensors may comprise instructing the first sensors to acquire the first set of sensor data. Obtaining the first set of sensor data using the one or more first sensors may further comprise receiving the first set of sensor data from the one or more first sensors, for example over a communications channel which may be wired or wireless. Information sufficient to determine the identity of the first owner of the 3D printed object means that it is possible to associate the information to a specific (e.g. unique) individual. That is, given the information recorded by the one or more first sensors, i.e. the first set of data, it is possible to select among all individuals a single individual who can be directly linked to the information, i.e., a single selected individual - wherein the selection is made using the information - is identified. This link between the first set of data recoded by the one or more first sensors and the individual is the identification of the individual.

Obtaining 102 the first set of sensor data using one or more first sensors may mean to acquire the first set of data using the one or more first sensors.

An identification of an individual using information comprised in the first set of data can be done in many different ways. Identification of an individual using information comprised in the first set of data means the information are enough to make a direct link to a unique individual. Many different types of information may lead to the identification of an individual. The individual can be identified for example by information containing the unique morphology of a body part of the individual. For example, the identification may be performed using a physical characteristic of the individual, such as fingerprints or other specific portion of anatomy (i.e. , structure of the retina, facial configuration, vein pattern, etc.). As an alternative or in addition, identification may be performed using information related to performing a task. For example, each individual has a specific way of performing a task that is individualspecific. For example, in the act of typing a document using a physical or virtual keyboard, such as a page of the same, each individual has a specific way of pressing keys of a keyboard. The pressing for example has a given frequency and individual-specific pauses between a stroke and the following one are performed. The same applies to an action of signing: the individual has a specific way of moving the hands, angling the bones of the hands while signing and the pressure exerted on the support where the signature takes place. Alternatively, information that allows the identification of an individual can relate to the environment where the individual is, for example information that identify a unique location and time.

The first set of sensor data which provide evidence of an identity of the first owner may comprise for example a photograph of a body part of the first owner, a fingerprint of the first owner, a handprint of the first owner, a heat signature map of the first owner, a scent of the first owner, or a typing pattern of the first owner.

In other embodiments of the invention, the first set of sensor data may comprise sensor data of a location connected to the first owner of the 3D printed object. The first set of sensor data of a location connected to the first owner may, for example, comprise the location of a user equipment, UE, belonging to the first owner. The UE may include a smart watch or a mobile phone. The first set of sensor data of a location connected to the first owner may comprise information about the location of the 3D printer used to create the 3D printed object. For example, in some embodiments of the invention as claimed, the location of the 3D printer may be recorded. If the 3D printer is located in a secured location, which the first individual has to access by means of an electronic key, logs of times when different individuals accessed the secured location and information about when the 3D printed object was manufactured may provide evidence of the identity of the first owner.

In some embodiments, the first set of sensor data may comprise information which provide evidence of a time connected to the first owner when the 3D printed object was manufactured. A time connected to the first owner of the 3D printed object may, for example, comprise a timestamp when the 3D printed object was manufactured. In an example, combined with information about the place where the 3D printed object was manufactured and which individuals had access to the location at that time, the timestamp may provide evidence of the identity of the first owner. In other examples, the timestamp may be combined with information about which individuals were logged in to or otherwise had access to a computer or an apparatus 401 (shown in Fig. 4) connected to the 3D printer used to manufacture the 3D printed object.

The one or more first sensors may, in embodiments, comprise one or more of: a camera, a fingerprint sensor, a handprint sensor, a satellite navigation system such as a global positioning service, GPS, sensor, a GLONASS, Global Navigation Satellite System, sensor, a Beidou sensor, a Galileo sensor, or a heat sensor, an artificial nose, a keyboard recorder, a capacitive or resistive touch sensor, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, or a medical sensor.

In embodiments of the invention, the one or more first sensors acquires the first set of sensor data at one specific point in time. For example, the one or more first sensors includes a camera, and the first set of data comprises a photograph of the owner at the time the 3D printed object is completed (e.g., the printing is finished). In other embodiments, the one or more first sensors acquire the first set of sensor data as a plurality of measurements which may be performed at regular intervals, at irregular intervals, or at random intervals. The first set of sensor data in this embodiment comprises data taken at different times. In other embodiments, the one or more first sensors acquire the first set of sensor data by measuring “continuously” over one or more periods of time. The period of time may be equal to the entire printing time from the beginning till the end of the 3D printing of the 3D printed object. The period of time may be one or more subsets of the entire printing time. The definition of a continuous measure depends on the type of the one or more first sensors. For example, if the one or more first sensors comprise a digital video camera, a continuous set of sensor data refers to a non-stop video recording with the maximal frame rate the video camera is capable of for one or more periods of time. If the one or more first sensors comprise an analogue sound recorder, a continuous set of sensor data may refer to a graphical representation of an audio curve on a suitable medium, with the highest possible resolution for one or more periods of time.

The first set of sensor data may comprise sensor data from a single sensor, or from multiple sensors. Sensor data may comprise multiple types of data - as an example the first set of sensor data may include a photograph of the first owner of the 3D printed object, metadata comprising information about the time the picture was taken, the location the picture was taken, and the device used to take the picture.

The method 100 may further comprise a step of selecting 109 a sensing technique to sense the identification mark of the 3D printed object. Selecting a sensing technique may, in embodiments, comprise selecting one or more second sensors to be used to sense the identification mark. The one or more second sensors may include one or more of: a camera, a thermometer, a voltmeter, an x-ray machine, a magnetometer, a Geiger counter, an RFID scanner, a densitometer, a radar sensor, a light detection and ranging, LiDAR, sensor, or a time-of-flight sensor. The sensing technique may include: image detection, temperature sensing, voltage sensing, x-ray image detection, magnetic field sensing, radioactivity sensing, RFID sensing, density sensing, radio detection, laser detection, or laser or light-emitting diode, LED, sensing. The sensing technique may also include manipulation of the 3D printed object, for example putting the 3D printed object in a pre-determined location or accelerating the 3D printed object at a given velocity. The skilled person understands that selecting the type of the one or more second sensors may depend on the properties of the identification mark.

Selecting a sensing technique may, in embodiments, comprise selecting the environmental conditions under which the selected one or more second sensors are to be operated. The environmental conditions under which the one or more second sensors are to be operated may for example comprise one or more of: a temperature range, a level of ambient light, a purity of the air, and others. Selecting a sensing technique may comprise selecting a setting for the selected one or more second sensors, called in the following second sensor setting. The second sensor setting for the selected one or more second sensors may comprise one or more of: an initializing voltage of an electric generator of the one or more second sensors, a temperature of the ambient environment the 3D printed object is in or a temperature of the 3D printed object, an intensity and/or wavelength of emitted light to be sensed by the one or more second sensors, or a position of the one or more second sensors relative to the 3D printed object.

The method 100 further comprises obtaining 102 a second set of sensor data using the selected sensing technique and the selected one or more second sensors. Obtaining the second set of sensor data using the one or more second sensors may comprise instructing the one or more second sensors to acquire the second set of sensor data using the selected sensing technique. Obtaining the second set of sensor data using the one or more second sensors may further comprise receiving the second set of sensor data from the one or more second sensors, for example over a communications channel which may be wired or wireless. The second set of sensor data may comprise a measurement related to the identification mark. Preferably, the second set of data comprises one or more measurements made by the one or more second sensors. In embodiments, depending on the properties of the selected one or more second sensors, the second set of sensor data may comprise one or more of: an electric resistance value measured when passing a current through the 3D printed object from a specified point on the 3D printed object, an x-ray image taken from a specified position relative to the 3D printed object, a measurement of the intensity of reflected light from a specified position relative to the 3D printed object, a photograph of a shadow of the 3D printed object, the shadow created when electromagnetic radiation impinges the 3D printed object from a selected position, a measurement of a frequency or intensity of a sound wave of a specified intensity transmitted from a specified position relative the 3D printed object when reflected off the 3D printed object, a measurement of polarized radiation or a specified wavelength reflected and/or passed through the 3D printed object from a specified position relative to the 3D printed object, a measurement of an intensity of a magnetic field of the 3D printed object, or a measurement obtained from a radio frequency identification, RFID, tag embedded in the 3D printed object. In embodiments, obtaining 102 the second set of sensor data may comprise performing a measurement using the selected sensing technique and the one or more second sensors with the selected second sensor setting. The selected second sensor setting is applied to the one or more second sensors before taking the measurements corresponding to the second set of sensor data. In an embodiment, applying the selected second sensor setting to the one or more second sensors comprises placing the one or more second sensors in a specified position relative to the 3D printed object. The specified position may be provided as for example Euclidean or spherical coordinates relative to an identifiable point of the 3D printed object. In an embodiment, applying the selected second sensor setting to the one or more second sensors comprises setting an initializing voltage value of or emitted wavelength value of the light emitted by the one or more second sensors. In an example, applying the second sensor settings to the one or more second sensors comprises manipulating the environmental conditions by for example adjusting the ambient light. The second set of sensor data may comprise measurements made by the one or more second sensor.

The sensing technique and the selected second sensor settings are linked. The properties of the sensing technique place limitations on the possible selected set of sensor settings - a video camera does not have an initializing voltage which affects the video recording, and an x-ray machine is only minimally affected by a change in ambient temperature. On the other hand, if the selected sensing technique comprises using a camera to sense the object, the sensor data will be affected by changing the location of the camera relative to the 3D printed object, and changing the ambient light in the location where the 3D printed object is located.

The second set of sensor data is in an embodiment the result of measurements performed by the one or more second sensors. For example, it may be the result of measurements performed by the one or more second sensors using the selected sensing technique. For example, it may be the result of measurements performed by the one or more second sensors using the selected sensing technique to which the second sensor setting has been applied.

The second set of sensor data may be obtained, e.g., acquired, when the 3D printed object is completely finished, e.g. the printer has printed the whole 3D object according to the file. Alternatively, the second set of sensor data may be obtained as soon as the identification mark is completely printed, even if the 3D printed object is not yet complete. This may happen for example when the identification mark comprises a 3D QR code embedded in the 3D printed object. In embodiments, obtaining 102 the second set of sensor data comprises simulating a behavior of the one or more second sensors according to the selected sensing technique so as to calculate an expected set of sensor data. In an embodiment, this may comprise using a computer including a processing unit configured to simulate the behavior of the one or more second sensors using the selected sensing technique in sensing the 3D printed object, which is also preferably simulated. Simulating the behavior of the one or more second sensors while sensing the 3D printed object includes obtaining a set of (simulated) measurements values of properties of the 3D printed object. In the simulation, the one or more second sensors preferably have the selected second sensor settings. Obtaining a set of simulated measurements may mean performing the simulation and computing the result (i.e. the measurements). Obtaining the set may mean instructing a processor to perform the simulation and receiving the result of the simulation as the measurements. The second set of sensor data comprises the output of the simulation. The second set of sensor data therefore comprises values that are “simulated measurements”, that is, values which are not the measurements of physical one or more second sensors, but simulations of the behavior of the one or more second sensors. In embodiments, the processing unit is configured to perform a simulation using a machine learning algorithm.

If the second set of sensor data is obtained by means of performing a simulation, the second set of sensor data may even be acquired before the 3D printing process has started, immediately after the identification mark has been inserted into the design file.

In embodiments, the simulating a behavior of the one or more second sensors according to the selected sensing technique so as to calculate an expected set of sensor data is performed using a digital twin of the 3D printed object.

In embodiments, the second set of sensor data may comprise both data acquired by physical one or more second sensors and simulated data outputted from a simulated one or more second sensors. The skilled person may appreciate that performing the measurement directly by “real” one or more second sensors and simulating the behavior of the one or more second sensors introduce different potential sources of errors and noise, which may be accounted for when evaluating the evidence supporting the provenance of the 3D printed object. The selection of the method for acquiring the second set of sensor data preferably depends on one or more of: the properties of the identification mark, the properties of the second set of sensors, and the availability of the second set of sensors at the time the second set of sensor data is acquired.

The method 100 further comprises creating 103 a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data. The provenance document is, in embodiments, a digital document. The indication of the selected sensing technique may comprise information about the one or more second sensors. In other embodiments the indication of the selected sensing technique may comprise information about the environmental conditions for acquiring the second set of sensor data. In other embodiments, the indication of the selected sensing technique may comprise information about the selected second sensor settings for the selected one or more second sensors.

The method 100 may further comprise storing 107 the created provenance document. The created provenance document may be stored in any location available to the first owner.

Storing 107 the provenance document may further comprise securing 108 the provenance document, as depicted in Fig. 1 b. The provenance document may, in embodiments, be added to a blockchain. In some embodiments, a hash value of the provenance document may be added to a blockchain and the provenance document secured in a different location.

In some embodiments of the method, evidence of ownership of the 3D printed object is provided by a first individual to enable the first individual to transfer ownership of the 3D printed object to a second individual. In these embodiments, the method may further comprise updating 110 the first set of sensor data in the provenance document to comprise a third set of sensor data related to an identity of the second individual. Updating the provenance document to comprise sensor data related to the identity of the second individual will make the second individual a second owner of the 3D printed object.

In some embodiments of the method 100 ownership of the 3D printed object is transferred from a first owner of the 3D printed object to a second owner of the 3D printed object. In other embodiments of the method 100, the second owner is added as an additional owner of the 3D printed object, and the 3D printed object becomes jointly owned by the first owner of the 3D printed object and the second owner of the 3D printed object.

In some embodiments of the method 100 where ownership is transferred from a first owner of the 3D printed object to a second owner of the 3D printed object, the first set of sensor data relating to the identity of the first owner is deleted from the provenance document when the third set of sensor data relating to the identity of the second owner are added. In other embodiments, the first data relating to the identity of the first owner is retained in the provenance document after a transfer of ownership. In other embodiments of the method 100, for example embodiments where the provenance document is stored on a blockchain or embodiments where a hash of the provenance document is stored on a blockchain, the storage method ensures that some information about all previous owners is retained. In embodiments, the third set of sensor data may comprise the same type of data as described with reference to the first set of sensor data.

Fig. 2a depicts a method 200 which may be used to obtain and examine evidence of ownership of the 3D printed object. The method may, for example, be performed by an apparatus 400 which can be referred to as a verification server.

The method 200 comprises obtaining 201 a provenance document. The provenance document may, for example, be stored securely on a server. Obtaining the provenance document may comprise receiving a transmission comprising the provenance document, for example over a wired or wireless communication channel. Obtaining the provenance document may comprise communicating a request for the provenance document to the server where it is stored and receiving a transmission comprising the provenance document over a wired or wireless communication channel. The communication channel may be secured, by for example encryption, to ensure the integrity of the provenance document. The provenance document has been already described with reference to the method of figures 1a and 1b.

When a requester wishes to determine ownership of the 3D printed object, the requester may communicate 108 via a wired or wireless communication channel with the verification server. The communication may use a graphic user interface, GUI, or may comprise the requester communicating with the verification server by entering machine-readable commands in a suitable programming language. In embodiments where the requester communicates with the verification server through a GUI, the requester may use a web application, or a mobile application developed specifically for the purpose of verifying the ownership of 3D printed objects created according to the method of this disclosure. Alternatively, the functionalities may be built into a more general-purpose web application or mobile application, such as an application for accessing NFT trading platforms.

The verification server may, in embodiments, comprise a network node in a wireless communication network, such as a mobile network according to any suitable 3GPP standard, or a Wi-Fi network according to any suitable IEEE standard. Alternatively, the verification server may be incorporated into an NFT trading platform, or an existing blockchain infrastructure.

The verification server may provide a one-time key 202 to the requester wishing to determine ownership of the 3D printed object. The one-time key comprises information enabling the requester to define a one-time setting of the one or more second sensors. The one-time setting of the one or more second sensors is a new setting for the one or more second sensors, not used by the one or more second sensors to obtain the second set of data. This one-time setting is a setting “similar” to the second sensor settings used to obtain the second set of sensor data. In an example, the one-time setting is defined as a new setting for the one or more second sensor calculated as follows: the selected second sensor settings as given in the provenance document for the one or more second set of sensors (to obtain the second set of sensor data) varied by a value delta. For example, the one-time key may provide only the delta. The provided delta may be called the one-time key. In some embodiments, the one-time setting is selected by the verification server such that the verification server may calculate, based on the one-time setting, on the second set of sensor data, and on the selected sensing technique, a fourth set of data comprising an expected result of measurements of the one or more second sensors using the second sensor setting with the exception of one second sensor setting which is replaced by the one-time setting.

For example, the delta defined by the one-time key may refer to one or more of: a changed position relative to the selected second sensor settings for the one or more second sensors, or a changed ambient temperature relative to the selected settings for the one or more second sensors, or a changed initializing voltage relative to the selected settings for the one or more second sensors. The delta may, in embodiments, apply to a single second sensor from the selected one or more second sensors. In other embodiments, the delta may apply to several second sensors from the selected one or more second sensors.

In some embodiments, the verification server may be further configured to only provide a one-time key to the requester if the request is made by a requester with an identity matching the identity of the first owner, which identity the first set of sensor data provide evidence of. In such embodiments, the verification server may request that the requester provides a fifth set of sensor data which may be compared by the verification server to the first set of sensor data accessible to the verification server. In embodiments, the verification server may use a measure of similarity to determine whether the fifth set of sensor data provided by the requester matches the first set of sensor data. In embodiments, the verification server may provide the one-time key only if the measure of similarity is above a predetermined first threshold.

The fifth set of sensor data comprises information related to an identity of a purported owner of the 3D printed object. In particular, the fifth set of data comprises information which may be compared to the information comprised in the first set of data. For example, if the first set of data comprises a voice recording of the first owner, then the fifth set of data comprises information which may be compared to a voice recording, such as a voice recording or a video recording of an individual speaking. If the first set of data comprises a fingerprint of the first owner, then the fifth set of data may comprise a fingerprint, a handprint, or geometric information related to a fingerprint, where corresponding geometric information may be extracted from the fingerprint comprised in the first data for comparison. In embodiments, the fifth set of sensor data may comprise the same type of data as described with reference to the first set of sensor data.

In some embodiments, the verification server may be configured to provide the onetime key only if the request for the one-time key is signed by a private key belonging to the first owner of the 3D printed object. In these embodiments, the first set of sensor data include information which enables the verification server to link the first owner to a public-private key pair. For example, the first set of sensor data may be signed with a public key available to the first owner.

The method 200 may further comprise receiving 204 a sixth set of sensor data. The method may comprise instructing the second set of sensors to sense the identification mark of the 3D printed object using the selected one or more second sensors and the selected one-time settings for the one or more second sensors, equal to the second sensor settings modified by the one-time key obtained from the verification server. The sensing may result in the sixth set of sensor data. The sixth set of data therefore may comprise information relative to the identification mark of the 3D printed object taken by the same one or more second sensors and same sensing technique but “slightly” different setting. The sixth set of data may be compared to the fourth set of data.

The method 200 may further comprise comparing 205 the obtained sixth set of sensor data to the fourth set of sensor data. The skilled person will appreciate that the result of the comparison between the sixth set of sensor data and the fourth set of sensor data may depend on the one-time key. Performing the comparison between the sixth set of sensor data and the fourth set of sensor data may therefore involve using the second set of sensor data and the one-time key to calculate the fourth of sensor data. For example, the second set of sensor data may include a value of a measurement of electrical conductivity when applying an electrical current with a specified initializing voltage v to a specified point of the 3D printed object. The one-time key may comprise instructions to increase the initializing voltage by a specific A so that the initializing voltage of the sensor is v + 4. The verification server may then be configured to calculate an expected measure of electrical conductivity when an initializing voltage v + A is applied to the specified point of the 3D printed object. The fourth set of sensor data comprises the calculated expected measure of electrical conductivity.

The fourth set of sensor data may be calculated when the verification server sends out a one-time key, or it may be calculated in association with the determination of the value of the one-time key, or it may be calculated on demand when a requester returns a sixth set of data to the verification server.

In embodiments, the fourth set of sensor data may not be identical to the sixth set of sensor data. Comparing the fourth set of sensor data to the sixth set of sensor data may therefore comprise calculating a measure of similarity between the fourth set of sensor data and the sixth set of sensor data. The skilled person will appreciate that which measure of similarity is calculated may depend on the properties and format of the sensor data.

In some embodiments of the invention, the method 200 may further comprise determining 210 a second threshold value for the measure of similarity (Fig. 2b). Determining a second threshold value may, in embodiments, comprise identifying 211 potential sources of noise for the second set of sensors. Determining a second threshold value may, in embodiments, further comprise quantifying 212 the magnitude of the potential sources of noise for the second set of sensors.

Determining a second threshold value may, in some embodiments, further comprise estimating a standard error of the fourth set of sensor data.

Determining a second threshold value may, in some embodiments, comprise using the accuracy of the 3D printer used to manufacture the 3D printed object to calculate a suitable second threshold value. In some embodiments where the 3D printed object was manufactured using a combination of additive manufacturing and subtractive manufacturing, determining a second threshold value may further comprise using the accuracy of the subtractive manufacturing process to determine a second threshold value.

In some embodiments of the method 200, the method may further comprise confirming 208 ownership of the 3D printed object if the calculated measure of similarity is above the determined second threshold value. In other embodiments of the method 200, the method may further comprise rejecting 209 ownership of the 3D printed object if the calculated measure of similarity is below the determined second threshold value.

Fig. 3 depicts an exemplary first apparatus 301 configured to collect the first set of sensor data and the second set of sensor data according to some embodiment of the invention. The first apparatus comprises a memory 302 and a processor 303. The first apparatus may have access to the one or more first sensors 306. The one or more first sensors may, in embodiments, be incorporated into the first apparatus. The one or more first sensors may comprise, for example, one or more of: a camera, a fingerprint sensor, a handprint sensor, a global positioning service, GPS, sensor, a heat sensor, an artificial nose, a keyboard recorder, a capacitive or resistive touch sensor, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, or a medical sensor. The first apparatus may further have access to the one or more second sensors 307 adapted to acquire the second set of sensor data. The one or more second sensors may comprise one or more of: a camera, a fingerprint sensor, a handprint sensor, a global positioning service, GPS, sensor, a heat sensor, an artificial nose, a keyboard recorder, a capacitive or resistive touch sensor, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, or a medical sensor.

For example, the one or more first sensors may comprise a camera which may be used to collect the first set of sensor data and the one or more second sensors may comprise an x-ray machine which may be used to collect the second set of sensor data. The camera and the x-ray machine may be integrated in the first apparatus. In other embodiments, the first apparatus may be equipped to communicate with the first set of sensors and/or the second set of sensors. The communication may be wired, over for example an Ethernet cable, or may be wireless, e.g. they may use for example Bluetooth as standardized in the IEEE 802.15.1 standard or any other suitable standard, Wi-Fi as standardized in the IEEE 802.11 standard or any other suitable standard, or a 3GPP protocol for mobile broadband communication such as Global System for Mobile Communications, GSM, Universal Mobile Telecommunications System, UMTS, Long-term Evolution, LTE, New Radio, NR, device-to-device sidelink communications, or future standards such as 6G and 7G. The first apparatus 301 may take any number of forms. It may, for example, comprise a mobile phone, a personal computer, a laptop, a smart device such as a smart watch, a 3D printer, or an Internet of Things, loT, device.

By way of example, the loT device for a home, an office, a building or an infrastructure may be a baking scale, a coffee machine, a grill, a fridge, a refrigerator, a freezer, a microwave oven, an oven, a toaster, a water tap, a water heater, a water geyser, a sauna, a vacuum cleaner, a washer, a dryer, a dishwasher, a door, a window, a curtain, a blind, a furniture, a light bulb, a fan, an air-conditioner, a cooler, an air purifier, a humidifier, a speaker, a television, a laptop, a personal computer, a gaming console, a remote control, a vent, an iron, a steamer, a pressure cooker, a stove, an electric stove, a hair dryer, a hair styler, a mirror, a printer, a scanner, a photocopier, a projector, a hologram projector, a 3D printer, a drill, a hand-dryer, an alarm clock, a clock, a security camera, a smoke alarm, a fire alarm, a connected doorbell, an electronic door lock, a lawnmower, a thermostat, a plug, an irrigation control device, a flood sensor, a moisture sensor, a motion detector, a weather station, an electricity meter, a water meter, and a gas meter.

By further ways of example, the loT device for use in a city, urban, or rural areas may be connected street lighting, a connected traffic light, a traffic camera, a connected road sign, an air control/monitor, a noise level detector, a transport congestion monitoring device, a transport controlling device, an automated toll payment device, a parking payment device, a sensor for monitoring parking usage, a traffic management device, a digital kiosk, a bin, an air quality monitoring sensor, a bridge condition monitoring sensor, a fire hydrant, a manhole sensor, a tarmac sensor, a water fountain sensor, a connected closed circuit television, a scooter, a hoverboard, a ticketing machine, a ticket barrier, a metro rail, a metro station device, a passenger information panel, an onboard camera, and other connected device on a public transport vehicle.

As further way of example, the communication loT device may be a wearable device, or a device related to extended reality, wherein the device related to extended reality may be a device related to augmented reality, virtual reality, merged reality, or mixed reality. Examples of such loT devices may be a smart-band, a tracker, a haptic glove, a haptic suit, a smartwatch, clothes, eyeglasses, a head mounted display, an ear pod or other type of headphones, an activity monitor, a fitness monitor, a heart rate monitor, a ring, a key tracker, a blood glucose meter, and a pressure meter.

As further ways of example, the loT device may be an industrial application device wherein an industrial application device may be an industrial unmanned aerial vehicle, an intelligent industrial robot, a vehicle assembly robot, and an automated guided vehicle.

As further ways of example, the loT device may be a transportation vehicle, wherein a transportation vehicle may be a bicycle, a motor bike, a scooter, a moped, an auto rickshaw, a rail transport, a train, a tram, a bus, a car, a truck, an airplane, a boat, a ship, a ski board, a snowboard, a snow mobile, a hoverboard, a skateboard, rollerskates, a vehicle for freight transportation, a drone, a robot, a stratospheric aircraft, an aircraft, a helicopter and a hovercraft.

As further ways of example, the loT device may be a health or fitness device, wherein a health or fitness device may be a surgical robot, an implantable medical device, a non-invasive medical device, and a stationary medical device which may be: an in-vitro diagnostic device, a radiology device, a diagnostic imaging device, and an x-ray device.

In embodiments of the invention, the first apparatus may be a central device in an loT network, and the first set of sensors and the second set of sensors may comprise sensors in the loT network.

Fig. 4 depicts a second apparatus 401 according to embodiments of the invention. The second apparatus is the verification server. The verification server comprises a processor 402 and a memory 403. The memory further comprises computer- readable instructions enabling the verification server to execute the steps of the method according to embodiments of the invention as described with reference to figures 2a and 2b. The verification server may further comprise a secure element 406, such as a trusted execution environment. The trusted execution environment may for example comprise Arm ® TrustZone® technology, or an AMD® platform security processor. Fig. 5 depicts an exemplary 3D printed object 500 according to embodiments of the method of the invention described in figures 1a, 1 b, 2a, and 2b of the invention. The 3D printed object comprises an identification mark 501 .

Fig. 6 depicts an exemplary 3D printer 600 according to embodiments of the invention. The 3D printer may be used to print the 3D printed object 500 of Fig. 5. The 3D printer comprises a nozzle 601 which deposits material on the tray 602. In embodiments of the invention, the nozzle is moveable and moves according to instructions received from the CAD file containing the sliced plan of the 3D printed object. In other embodiments of the invention, the shelf is moveable and moves according to instructions received from the CAD file containing the sliced plan of the 3D printed object. In other embodiments, the nozzle and shelf are both moveable and shift as the 3D printed object is being manufactured. In some embodiments of the invention, the 3D printer is further configured to communicate with a computer comprising a processor and a memory. In some embodiments, the 3D printer comprises the apparatus 301 . Alternatively or in addition, the apparatus 301 may comprise the 3D printer 500.

Fig. 7 depicts an exemplar flow of communications between a requester with access to the 3D printed object 500, the second apparatus 401 , and the one or more second sensors for providing evidence of ownership of a 3D printed object. The communication is initiated by the requester who sends a request 701 to the verification server for providing a one-time key. The second apparatus 401 responds to the request by checking 702 whether the request is valid. In embodiments, valid means that it was made by a requested with an identity matching the identity of the first owner according to the first data available to the verification server, up to some predetermined margin of error. Checking may thus comprise comparing the fifth data sent with the request to the first data to determine if it supports the proposition that the requester has the same identity as the first owner.

If the request is found to be valid, the verification server will transmit 703 the onetime key and the selected settings. The one-time key and the selected settings may be provided to the one or more second sensors directly. In other embodiments, the one-time key and the selected settings may be provided to the requester. The settings of the one or more second sensors are adjusted 704, either by the one or more second sensors, or by a controller for the sensors, or by a human able to adjust the required settings to match the selected settings modified by the one-time key as communicated by the verification server to obtain the one-time settings of the one or more second sensors. The second set of sensors, using the one-time settings according to the one-time key, obtain 705 the sixth set of sensor data. The sixth set of sensor data is transmitted 706 to the verification server. Obtaining the sixth set of sensor data using the one or more second sensors may comprise instructing the one or more second sensors to acquire the second set of sensor data using the selected sensing technique. Obtaining the sixth set of sensor data using the one or more second sensors may further comprise receiving the second set of sensor data from the one or more second sensors, for example over a communications channel which may be wired or wireless.

The verification server will compare 707 the fourth set of sensor data to the sixth set of sensor data. The result of the comparison is, in embodiments, compared to the pre-determined second threshold. If the level of similarity between the fourth set of data and the sixth set of sensor data is above the second threshold, the verification server will confirm that there is evidence of ownership of the 3D printed object. If the level of similarity between the fourth set of data and the sixth set of sensor data is below the second threshold, the verification server will reject that there is evidence of ownership of the 3D printed object. The verification server will then transmit 708 the rejection or confirmation to the requester. In other embodiments, the verification server will not evaluate the output of the comparison and will instead transmit 708 the output and the requester may evaluate the evidence.

Fig. 8 depicts an exemplary flow of communication between a requester, a second set of sensors, and a verification server for transferring ownership of a 3D printed object. Steps 801 to 808 are identical to steps 701 to 708 of Fig. 7.

If the requester and the buyer are satisfied that ownership has been confirmed 809, ownership can be transferred. The buyer provides a third set of data, comprising sensor data related to an identity of the buyer. The third set of data have the same properties as the first set of data related to an identity of the first owner, or it may have different properties. The third set of data is transmitted 810 to the verification server. The verification server may update 811 the provenance document with the third set of data. In embodiments of the invention, the third set of data is added to the provenance document, but the first set of data remains unchanged. In other embodiments of the invention, the third set of data replaces the first set of data.

Finally, the verification server communicates 812 to the requester that the ownership of the 3D printed object has been successfully transferred.

A non-limiting example of the invention is provided. In this example, a first individual wishes to create and assure the provenance of a decorative bowl based on a design file created in a CAD program. The 3D printed object is the decorative bowl. The first individual registers to a service which provides verification server services according to an embodiment of the invention. The first individual provides the design file and information about the 3D printer which the first individual plans to use to create the object (the bowl) to the verification server, which uses those documents to initialize a provenance document. The 3D printer may, for example, be an Anycubic™ Kobra Max.

The service provides the 3D printer with information sufficient for the 3D printer to include a hidden identification mark in the design file. In this example, the hidden identification mark comprises a series of fluorescent inclusions on the exterior of the object. The precise properties of the inclusion is known only to the verification server, the slicer, and the 3D printer. The verification server uses the information about the 3D printer to determine an identification mark which the 3D printer is capable of manufacturing.

The updated design file including the fluorescent inclusion is provided to a slicer, which prepares the updated design file for the 3D printing process by slicing the updated design plan and providing it to the 3D printer.

The 3D printer manufactures the bowl with the fluorescent inclusions according to the updated design plan.

In this embodiment, the first set of data is collected by a camera mounted in the room where the 3D printing process happens, and the first set of data comprises a series of photographs taken every 30 seconds showing the production process and the first individual initializing the process from a computer connected to the 3D printer and supervising the printing process. The verification server selects one or more second sensors and a sensing technique for the one or more second sensors based on the properties of the identification mark. In this embodiment, the one or more second sensors are a camera and a light source, and the sensing technique comprises light irradiation. The setting of the one or more second sensors may comprise a selected ambient light and a frequency of emitted light from the light source(s) which together enable a camera to detect the fluorescent inclusions in the bowl. The setting furthermore may comprise the position of the camera and the position of the light source as detailed below.

The second set of data is collected by the one or more second sensors using the selected sensing technique. In this embodiment, the light source emits light towards the object, from a specified position relative to the object, in order to measure the number of visible fluorescent inclusions in the bowl. The specified position of the camera and/or of the light source is given with respect to the bowl and it is indicated for example as a triplet of coordinates (r, 6, cp,) where r is a Euclidean distance from the center of mass of the bowl, 6 is a polar angle relative to the horizontal surface the bowl is resting on, and cp is an azimuthal angle. The frequency of the light and the ambient light in the room are selected to ensure that the fluorescent inclusions are visible to the camera.

The second set of data, in the form of a photograph of the inclusions, is streamed to the verification server and added to the provenance document.

Based on the second set of sensor data in the provenance document, the verification server calculates a tolerance associated to the second set of sensor data which may be used in the evaluation process. For example, the selected settings for the one or more second sensors may result in 3 out of 5 inclusions being visible in the photograph comprised in the second set of data. Moreover, the fluorescent inclusions have a position in the photograph, and a shape in the photograph, which depend on the selected position of the camera. The verification server determines a suitable tolerance for the number of visible fluorescent inclusions, their position, and their shape.

The creation of the 3D printed object and associated provenance document is now complete. In this embodiment of the invention, the verification server protects the provenance document by only responding to requests signed by a private key belonging to the first individual, and with an attached photograph which the verification server determines with accuracy > 98% portrays the same individual as the first data, using an Al powered image recognition algorithm.

If a second individual wishes to ascertain the provenance of the 3D printed object, before for example purchasing the object, the second individual may send a request to the verification server, indicating the specific object the second individual wishes to ascertain the provenance of. The request is signed by a private key belonging to the first individual and comprises a photograph of the first individual. The photograph of the first individual comprises the fifth data.

The verification server responds by calculating a A which is an adjustment in the relative position of the camera which will be used to create the fourth set of data and the sixth set of data. In this embodiment, the A comprises a modification of the polar angle 9 of the camera position by n/10. With this setting the verification server, based on the information about the bowl in the provenance document, determines that one additional inclusion becoming visible and change the shape of the inclusions in the photograph. The new number of inclusions, 4, and the calculated changed shapes and sizes of the inclusions comprise the fourth set of data.

The second individual receives the information about the adjusted settings of the second scanning device and takes the photograph from the described position under the stated conditions. The photograph, which comprises the sixth set of data, is sent to the verification server. The verification server evaluates the photograph compared to the fourth set of data using an Al-powered image processing algorithm. If the algorithm determines with > 90% that the photograph matches the expectation, then the verification server transmits to the second user that the evidence supports the proposition that the object is the same as the one in the provenance document, and the first individual is the owner.

The second individual now has evidence of the provenance of the bowl, and can proceed with the purchase with some level of evidence that the bowl is the original and the first individual is the owner. The second individual provides the verification server with a third set of data related to the identity of the second individual. In this embodiment, the third set of data comprises a handprint of the second individual. Additionally, the second individual signs the third data with a private key accessible to the second individual. The verification server incorporates the third data into the provenance document and records information about the signature of the second individual and transmits an acknowledgement that the ownership of the bowl has been transferred.

Claims

1 . A method (100) for providing evidence of ownership of a three-dimensional, 3D, printed object (500) having an identification mark (501 ), the method comprising: obtaining (101 ) a first set of sensor data, associated to an identity of a first owner of the 3D printed object, the first set of sensor data being acquired using one or more first sensors (306), obtaining (102) a second set of sensor data, the second set of sensor data being acquired using a selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors (307), creating (103) a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data.

2. The method according to claim 1 , comprising: receiving (104) a digital file of the 3D printed object; and instructing (105) a 3D printer to print the 3D printed object with the identification mark.

3. The method according to claim 1 or 2, comprising: instructing (106) the one or more first sensors to record the first set of sensor data.

4. The method according to one or more of claims 1 -3, further comprising storing (107) the provenance document.

5. The method according to claim 4, wherein storing (107) the provenance document comprises securing (108) the provenance document.

6. The method according to claim 5, wherein securing (108) the provenance document comprises adding the provenance document to a blockchain.

7. The method according to claim 5 or 6, wherein securing (108) the provenance document comprises adding a hash value of the provenance document to a blockchain.

8. The method according to one or more of the preceding claims, wherein the first set of sensor data comprises sensor data which provide evidence of the identity of the first owner of the 3D printed object (500).

9. The method according to one or more of the preceding claims, wherein the first set of sensor data comprises sensor data which provide evidence of a location connected to the first owner where the 3D object (500) was manufactured.

10. The method according to one or more of the preceding claims, wherein the first set of sensor data comprises sensor data which provide evidence of a time connected to the first owner when the 3D object (500) was manufactured.

11 . The method 100 according to one or more of the previous claims, comprising: providing the 3D printed object with the identification mark (501).

12. The method according to claim 11 or 2, wherein the identification mark (501 ) comprises a pseudorandom mark inserted into the 3D printed object (500) during the production of the 3D printed object (500).

13. The method according to one or more of the preceding claims, comprising: selecting (109) a sensing technique to sense the identification mark of the 3D printed object.

14. The method according to claim 13, wherein the selected sensing technique for acquiring the second set of sensor data depends on the properties of the identification mark (501 ).

15. The method according to claim 13, wherein selecting (109) the sensing technique comprises selecting environmental conditions for acquiring the second set of sensor data.

16. The method according to one or more of claims 13 - 15, wherein selecting (109) the sensing technique comprises selecting second sensor settings for the one or more second sensors (307) used to acquire the second set of sensor data.

17. The method according to one or more of claims 13-16, wherein obtaining (102) the second set of sensor data comprises obtaining a measurement result using the selected sensing technique and the one or more second sensors (307) for acquiring the second set of sensor data.

18. The method according to claims 16 and 17, wherein obtaining a measurement result using the selected sensing technique and the one or more second sensors (307) for acquiring the second set of sensor data includes obtaining measurement result using the selected sensing technique and the one or more second sensors (307) in which the selected second sensor settings have been set up.

19. The method according to one or more of the previous claims, wherein obtaining (102) the second set of sensor data comprises obtaining a result of a simulation of a behavior of the one or more second sensors (307) according to the selected sensing technique so as to calculate an expected set of sensor data, wherein the second set of sensor data comprises the expected sensor data.

20. The method according one or more of the preceding claims, wherein obtaining (102) the second set of sensor data is performed after the 3D printed object is completed.

21 . The method according to one or more of the previous claims, wherein obtaining (102) the second set of sensor data is performed during the production of the 3D printed object.

22. The method according to any one of claims 1-19, further comprising receiving an updated (110) first set of sensor data in the provenance document to comprise a third set of sensor data related to an identity of a second owner.

23. A method (200) for providing evidence of ownership of a three- dimensional, 3D, printed object (500), the method comprising: obtaining (201 ) a provenance document comprising a first set of sensor data, an indication of a sensing technique, and a second set of sensor data, wherein the first set of sensor data is associated to an identity of a first owner of the 3D printed object, and is acquired using one or more first sensors, and the second set of sensor data is obtained using the selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors having selected second sensor settings; providing (202) a requester with a one-time key, wherein information included in the one-time key is used to define a one-time second sensor setting for one or more of the second sensors (307); calculating (203) a fourth set of sensor data as a function of the second set of sensor data and the one-time second sensor setting; receiving (204) a sixth set of sensor data, obtained by sensing the identification mark using the selected sensing technique and the one or more second sensors (307), the one or more second sensor having the selected second sensor settings, wherein one of the selected second sensor settings has been replaced with the one-time second sensor setting; comparing (205) the fourth set of sensor data to the sixth set of sensor data.

24. The method (200) according to claim 23, wherein providing a requester with a one-time key is performed only if the requester has an identity matching the identity of the first owner as identified by the first set of sensor data.

25. The method (200) according to claim 24, comprising: receiving (206) a fifth set of sensor data, the fifth set of sensor data comprising information relative to the identity of the requester.

26. The method (200) according claim 25, comprising: comparing (207) the fifth set of sensor data to the first set of sensor data.

27. The method (200) according to claim 26, wherein comparing (207) the fifth set of sensor data to the first set of sensor data comprises calculating a first measure of similarity between the fifth set of sensor data and the first set of sensor data and comparing the first measure of similarity to a first threshold value.

28. The method (200) according to one or more of claims 21-27, wherein providing a one-time key is performed only if a request for the one-time key is received and the request is signed by a private key belonging to the first owner of the 3D printed object.

29. The method according to one or more of claims 23 - 28, wherein comparing (205) the fourth set of sensor data to the sixth set of sensor data comprises determining a second measure of similarity between the sixth set of sensor data and the fourth set of sensor data.

30. The method according to claim 29, wherein comparing (205) the fourth set of sensor data to the sixth set of sensor data comprises comparing the second measure of similarity to a second threshold value.

31. The method according to claim 30, comprising confirming (208) ownership of the 3D printed object by the requester if the second measure of similarity is above the second threshold value.

32. The method according to claim 30, comprising rejecting (209) ownership of the 3D printed object by the requester if the second measure of similarity is below the second threshold value.

33. A first apparatus (301) for providing evidence of ownership of a three- dimensional, 3D, printed object (500) having an identification mark (501 ), the apparatus configured to: obtain (101 ) a first set of sensor data, associated to an identity of a first owner of the 3D printed object, using one or more first sensors (306), obtain (102) a second set of sensor data using a selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors (307), and create (103) a provenance document comprising the first set of sensor data, an indication of the selected sensing technique, and the second set of sensor data.

34. The first apparatus of claim 33, configured to: receive (104) a digital file of the 3D object; and instruct (105) a 3D printer to print the 3D printed object (500) with the identification mark (501 ).

35. The first apparatus according to claim 33 or 34, configured to: instruct (106) the first set of sensors (306) to record the first set of sensor data.

36. The first apparatus according to any one or more of claims 33-35, further configured to storing (107) the provenance document.

37. The first apparatus according to claim 36, wherein storing the provenance document further comprises securing (108) the provenance document.

38. The first apparatus according to claim 37, wherein securing (108) the provenance document comprises adding the provenance document to a blockchain.

39. The first apparatus according to claim 37 or 38, wherein securing (108) the provenance document comprises adding a hash value of the provenance document to a blockchain.

40. The first apparatus (301 ) according to any one or more of claims 33-39, further configured to: provide the 3D printed object with the identification mark.

41 . The first apparatus (301 ) according to claim 40, wherein the identification mark comprises a pseudorandom mark inserted into the 3D printed object during the production of the 3D printed object.

42. The first apparatus (301 ) according to any one or more of claims 33-41 , further configured to: select (109) a sensing technique to sense the identification mark (501 ) of the 3D printed object.

43. The first apparatus (301 ) according to claim 42, wherein select (109) a sensing technique comprises selecting environmental conditions for acquiring the second set of sensor data.

44. The first apparatus (301 ) according to any one or more of claims 41 -43, wherein select (109) the sensing technique comprises selecting second sensor settings for the one or more second sensors used to acquire the second set of sensor data.

45. The first apparatus (301 ) according to any one or more of claims 41 -44, wherein obtain (102) the second set of sensor data comprises obtaining a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data.

46. The first apparatus (301 ) according to claims 44 and 45, wherein obtain a measurement result using the selected sensing technique and the one or more second sensors for acquiring the second set of sensor data includes obtaining a measurement result using the selected sensing technique and the one or more second sensors in which the selected second sensor settings have been set up.

47. The first apparatus (301 ) according to any one or more of claims 33-46, wherein obtain the second set of sensor data comprises obtaining a result of a simulation of a behavior of the one or more second sensors according to the selected sensing technique so as to calculate an expected set of sensor data, wherein the second set of sensor data comprises the expected sensor data.

48. The first apparatus (301 ) of any one or more claims 33-47, further configured to receive (110) an updated first set of sensor data and adding the updated first set of sensor data to the provenance document to comprise a third set of sensor data related to an identity of a second owner.

49. A second apparatus (401 ) for providing evidence of ownership of a three- dimensional, 3D, printed object, the second apparatus configured to: obtain (201 ) a provenance document comprising a first set of sensor data, an indication of a sensing technique, and a second set of sensor data, wherein the first set of sensor data is associated to an identity of a first owner of the 3D printed object, using one or more first sensors, and the second set of sensor data is obtained using the selected sensing technique to sense the identification mark of the 3D printed object and one or more second sensors having selected second sensor settings; provide (202) a requester with a one-time key, wherein information included in the one-time key is used to define a one-time second sensor setting of the one or more second sensors; calculate (203) a fourth set of sensor data as a function of the second set of sensor data and the one-time second sensor setting; receive (204) a sixth set of sensor data, obtained by sensing the identification mark using the selected sensing technique and the one or more second sensors, the one or more second sensors having the selected second sensor settings, wherein one of the selected second sensor settings has been replaced with the one-time setting; compare (205) the fourth set of sensor data to the sixth set of sensor data.

50. The second apparatus (401 ) according to claim 49, wherein providing a requester with a one-time key is performed only if the requester has an identity matching the identity of the first owner as identified by the first set of sensor data.

51 . The second apparatus (401 ) according to claim 50, further configured to receive (206) a fifth set of sensor data, the fifth set of sensor data comprising information relative to the identity of the requester.

52. The second apparatus (401 ) according to claim 51 , further configured to compare (207) the fifth set of sensor data to the first set of sensor data.

53. The second apparatus (401 ) according to claim 52, wherein comparing the fifth set of sensor data to the first set of sensor data comprises calculating a first measure of similarity between the fifth set of sensor data and the first set of sensor data and comparing the first measure of similarity to a first threshold value.

54. The second apparatus (401 ) according to any one or more of claims 49-

53, wherein provide a one-time key is performed only if a request for the one-time key is received and the request is signed by a private key belonging to the first owner of the 3D printed object.

55. The second apparatus (401 ) according to any one or more of claims 49-

54, wherein compare the fourth set of sensor data to the sixth set of sensor data comprises determining a second measure of similarity between the sixth set of sensor data and the fourth set of sensor data.

56. The second apparatus (401 ) according to claim 55, wherein comparing the fourth set of sensor data to the sixth set of sensor data comprises comparing the second measure of similarity to a second threshold value.

57. The second apparatus (401) according to claim 55, configured to confirm ownership of the 3D printed object by the requester if the second measure of similarity is above the second threshold value.

58. The second apparatus (401 ) according to claim 55, configured to reject ownership of the 3D printed object by the requester if the second measure of similarity is below the second threshold value.

59. A computer program (304), comprising instructions which when run on a processor belonging to an apparatus, causes the apparatus to perform a method according to any one of claims 1-22.

60. A computer program product (305), comprising a computer readable storage medium on which a computer program according to claim 59 is stored.

61 . A computer program (404), comprising instructions which when run on a processor belonging to a server causes the server to perform a method according to any one of claims 23-32.

62. A computer program product (405), comprising a computer readable storage medium on which a computer program according to claim 61 is stored.