Abstract: A method comprises: receiving, at a secondary printer module, an attestation challenge generated by a primary printer module; deriving, from a set of executable instructions encoded on a non-transitory machine-readable storage medium of the secondary printer module, a private key: generating, from the attestation challenge and the private key, a response to the attestation challenge; and communicating the response to the primary printer module.

Abstract: A non-transitory computer readable medium is provided. The computer readable medium is encoded with instructions which when executed by a processor, cause the processor to receive a certificate of authentication from an authentication entity, the certificate of authentication certifying that a user has been authenticated by the authentication entity, verify the certificate of authentication, receive a cryptographic key associated to the user, generate a secure ledger transaction request, the transaction request comprising the cryptographic key, identification data associated to the user and the certificate of authentication and communicate the transaction request to the secure ledger.

Abstract: According to an example, a method to certify 3D objects comprises receiving a request to certify a 3D object printed by a 3D printer, obtaining printer state data relating to a recorded state of the 3D printer and intended state data relating to an intended state of the 3D printer at a time when the 3D object was printed, determining if the recorded state of the 3D printer is in compliance with the intended state of the 3D printer, and approving the request to certify the 3D object if the recorded state is determined to be in compliance with the intended state.

Abstract: According to examples, a method comprises obtaining a digital representation of a three-dimensional object, mapping the digital representation on to a sphere of a pre-determined radius and generating a descriptor of the digital representation based on a spherical harmonic decomposition of an output of the mapping.

Abstract: According to examples, a method comprises obtaining a digital representation of a three-dimensional object, mapping the digital representation on to a sphere of a pre-determined radius and generating a descriptor of the digital representation based on a spherical harmonic decomposition of an output of the mapping.

Abstract: According to examples, an apparatus includes a processor that is to receive a transaction for a smart contract on a blockchain to progress a state of a workflow instance of the smart contract. The processor is to identify a rule correlated to the received transaction among a set of rules for the smart contract and is to load the identified rule correlated to the received transaction into the smart contract. The processor is to determine whether the received transaction is valid based on application of the identified rule in the smart contract. Based on a determination that the received transaction is valid based on application of the identified rule, the processor is to progress the state of the workflow instance of the smart contract.

Abstract: In one example in accordance with the present disclosure, an electronic device is described. The example electronic device includes a processor and a memory communicatively coupled to the processor. The memory stores executable instructions that when executed cause the processor to store data received from a first entity in a blockchain ledger based on a smart contract. The instructions also cause the processor to verify, with the smart contract, that a second entity is authorized to receive the data. The instructions further cause the processor to send the data to the second entity in response to verifying the second entity is authorized to receive the data.

Abstract: An example method for use in additive manufacturing comprises operating, by a processor, on object model data, the object model data describing an object to be generated in an additive manufacturing process. The example method comprises determining, by a processor, based on the object model data, whether a portion of the object to be generated is identified as an object of interest. In response to a determination that a portion of the object to be generated is identified as an object of interest, then the method comprises determining, by a processor, whether a policy-based action is associated with the object of interest. In response to a determination that a policy-based action is associated with the object of interest, then the method comprises executing, by a processor, the policy-based action, and generating, by a processor, the object according to the policy-based action.

Abstract: Apparatuses and methods for scanning a flow of parts or products of many various types and formats. The apparatus comprises a plurality of light sources and a plurality of detectors located around a scanning volume to observe build parts or products in the scanning volume from different observation angles, the light sources each to direct light of separate wavelengths over a respective field of view. Each detector has at least one filter to isolate at the detector light from one of the light sources from light from the other of the light sources. The apparatus also includes a controller to operate a plurality of the light sources, detectors and filters to form measurement groups to scan the observable surface of objects in the scanning volume simultaneously from different observation angles, to obtain scanning data for generating a 3D model.

Abstract: According to examples, a three-dimensional (3D) fabrication system may include a fabrication component, a monitoring component, and a controller. The controller may access a record specifying an identification of a parameter to be monitored during a fabrication operation of a part, cause the fabrication component to fabricate the part, and cause the monitoring component to monitor the parameter during fabrication of the part and generate data corresponding to the monitored parameter. The controller may also cause the generated data to be recorded in a blockchain ledger.

Abstract: In an example there is provided a method for certifying transactions of a workflow for a workflow comprising a set of transactions and a permitted order of execution of transactions. The method comprises generating verification data in response to a request from a client to certify a transaction of the workflow on the basis of a secure ledger where the verification data certifies the validity of the secure ledger. The method further comprises communicating the verification data to the client. The secure ledger is determined on the basis of workflow transactions.

Abstract: In some examples, there is provided a method, comprising receiving data encrypted using an encryption key, querying a digital ledger sewer for rights associated with the received data, recording, at the digital ledger server, a request to perform an access/process operation on the data, decrypting the data using a decryption key, and determining, using the rights, whether a rendering device is authorised to access and/or process the data.

Abstract: The present disclosure pertains to systems and methods of secure printing to preserve proprietary content. In some examples, a system may include utilizing a verifiable content summary with a lower resolution version of the content and a full-detail distinguishing excerpt of the content. In some examples, the system may provide a user with a verifiable content summary to facilitate authentication of a received physical content item.

Abstract: A method tor regulating production of an object, the method comprising allocating access rights and a production quota to a user, the production quota to be fulfilled on an authorised production device using an encrypted unique job token embedded or comprised within or derived from the object and associated with the user and production device, receiving a user request to produce the object at the authorised production device, authenticating the user, decrypting the encrypted unique job token using a private key of the user and a private key of the production device, determining whether the production quota for the user related to the object has been met and on the basis of the determination, authorising the user request to produce the object at the authorised production device.

Abstract: In an example, a data structure comprises a first genesis record having an associated authentication value and a plurality of subsequent records arranged in an order, wherein at least one subsequent record includes the authentication value associated with the first genesis record and an authentication value associated with another record in the data structure. A method may include designating one of the subsequent records as a second genesis record, acquiring an authentication value for the second genesis record, deleting at least one record preceding the second genesis record in the data structure and adding a further record to the data structure wherein the further record includes the authentication value of the second genesis record and an authentication value associated with a directly preceding record in the data structure.

Abstract: Object model data modification is described in which object model data defining a three dimensional model to be generated by a three-dimensional printer may be obtained. Data relating to a first sensitive portion of the model may be obtained, the first sensitive portion representing a portion of the model to be concealed. Modified object model data in generated, the modified object model data including a first version of the three dimensional model that is represented in a first pre-processing application without exposing the first sensitive portion, and including the first object model data defining the three dimensional model for printing by a three-dimensional printer.

Abstract: A method for regulating modification of a distributed digital ledger at a node comprises controlling access to a cryptographic key used to enable modification of the distributed digital ledger according to a policy maintained by at least one owner of the distributed digital ledger.

Abstract: Examples associated with digital composition hashing are described. One example method includes receiving a digital composition file from a user. The digital composition file may include a top-level design and a hierarchy of sub-level designs. A hashed structure may be generated from the digital composition file, where a node in the hashed structure for the first sub-level design is generated based on hashes of sub-level designs below the first sub-level design in the hierarchy. The hashed structure and a hash of the digital composition file are stored in association with the user.

Abstract: A method and system for certifying an interaction of an infrastructure component with a device in the course of the device lifecycle are described. The method comprises accessing device identification data that identifies the device, generating validation data on the basis of device identification data and component identification data to certify an interaction of the device with the infrastructure component and communicating a request to store the validation data in a secure ledger. The secure ledger comprises a ledger entry for each interaction of the device with an infrastructure component.

Abstract: In an example, there is provided a method for creating a workflow, comprising workflow tasks. The method comprises assigning workflow tasks to workers, according to an access control policy. The method comprises encoding as a transaction to a secure ledger that access to the workflow is granted to a worker to perform a workflow task and enforcing access control on execution of the workflow task according to the transaction encoded to the secure ledger.