WO2018087493A1

WO2018087493A1 - System and method for secure transfer and identified and traceable use of proprietary computer files

Info

Publication number: WO2018087493A1
Application number: PCT/FR2017/053082
Authority: WO
Inventors: Vasile Andrei MITUCA; Alexandre Guerin; Antoine JEOL
Original assignee: 3Dtrust
Priority date: 2016-11-14
Filing date: 2017-11-13
Publication date: 2018-05-17
Also published as: FR3058856B1; FR3058856A1

Abstract

The invention relates to a system and method for secure transfer and identified and traceable use of computer files between a machine hosting proprietary computer files, known as a file host (6), and a machine requesting the receipt and use of at least one of said proprietary computer files, known as a file client (7), said machines being connected to a network, said private machine network (5) comprising at least one central server (8) and a database formed of a chain of ordered blocks, known as a blockchain (9), distributed on the private network (5) and associated with a write-read protocol and cryptographic validation of transactions performed on the private network, said file host (6) and said file client (7) being further connected to each other by a secure transmission channel dedicated to the transfer of proprietary computer files.

Description

SYSTEM AND METHOD FOR SECURE TRANSFER AND IDENTIFIED AND TRACEABLE USE OF FILES

COMPUTER OWNERS

1. Technical field of the invention

The technical field of the invention is that of systems and methods for securing the exchange of data between two machines. The invention more particularly relates to a system and a method for secure transfer and traceable use of proprietary computer files. 2. Technological background

Throughout the text, a proprietary computer file designates a set of digital codes adapted to be directly or indirectly interpreted by a machine, such as a computer, a numerically controlled machine, an additive manufacturing machine, and in a manner general any machine equipped with a microprocessor. The computer file is said to be proprietary since the creator of the file or his trustee intends to control access and use of the file. Such a proprietary computer file is for example a software intended to be installed and executed on a computer, a printing file intended for an additive manufacturing machine, such as a 3D printer, an image file, a video file, a file textual, etc.

Today, most of the computer file transfer operations between two parties is done directly, for example by sending an email from one party to another, or by making the file available on a server. FTP or any equivalent means. In order to secure the transfer of a computer file, it is encrypted with a key that is known to each party to encrypt and decrypt the file. This simple method gives the file protection against fraudulent access by a third party whose security level is closely related to the type of key used and its backup mode. On the other hand, this simple process does not make it possible to trace the use that is made of the file once received by one of the parties. Moreover, it does not provide any tangible evidence that the transfer took place.

The emergence of additive printing technologies, more commonly known as 3D printing, requires the implementation of new methods of securing data transfers.

In particular, a 3D object can be associated with a variety of intellectual property rights (protection of the form of the object by a model, protection of the functionality of the object by a patent, protection of the originality of the object by a copyright, protection of the sign formed by the object by a three-dimensional mark, etc.).

It is therefore necessary to promote the emergence of these technologies and generally to favor all technologies using proprietary computer files, to have a solution that makes it possible to secure the transfer of a proprietary computer file. party to another, and who can guarantee that intellectual property rights are respected.

Patent document EP2757736 dedicated to 3D printing files proposes not to transmit the print files as such but to transmit only the control instructions of the 3D printer (known for example under the name of G- codes), these instructions being themselves encrypted with a key known only to the 3D printer considered. Thus, the content of the print file does not circulate on the network and only the machine control instructions are transmitted from a server to the machine, which avoids interception of the print file. In other words, the solution proposed by EP2757736 makes it possible to prevent a third party from recovering the source file of the object to be printed.

However, this solution does not guarantee that only a copy of the piece will be produced from the order instructions. Indeed, from the moment the commands are received by the 3D printer, nothing prevents the manufacture of a plurality of parts from the control instructions of the machine. In other words, if the proposed solution seems to authorize the securing of the data with regard to third parties, it does not allow the holder of a right on the object to be printed to check the use made of the instructions transmitted to the printer. In particular, the proposed solution does not make it possible to trace the use of the instruction commands of the 3D printer.

It is therefore essential to promote the emergence of these additive printing technologies, and generally to favor all technologies using proprietary computer files, to have a solution that makes it possible to secure the transfer of a computer file from one party to another, to guarantee that this transfer has taken place, and to trace the use made of the transferred file.

3. Objectives of the invention

The aim of the invention is to provide a method and system for the secure transfer of proprietary computer files that overcomes at least some of the disadvantages of known solutions.

The invention aims in particular to provide, in at least one embodiment, a method and a system for secure transfer of computer files that track and trace the use that is made of the transferred computer file.

The invention also aims to provide, in at least one embodiment, a method and a system for transferring computer files that guarantee the inviolability of the files.

The invention also aims to provide, in at least one embodiment, a method and a system for transferring computer files that guarantee inalterability of the transmitted files.

The invention also aims to provide, in at least one embodiment, a method and a system for transferring computer files that make it possible to authenticate each of the parties involved in the transfer operation.

The invention also aims to provide, in at least one embodiment, a method and a system for transferring computer files that provide information on the quality of the use of the transferred file, including a quality of 3D printing in the case of a proprietary computer file for a 3D printer.

4. Presentation of the invention

To do this, the invention relates to a secure transfer system and identified use of computer files between at least one machine hosting said proprietary computer files, said file host, and at least one machine requesting the reception and use of computer files. at least one of said proprietary computer files, said file client, said system comprising:

a network of machines, said private network, comprising at least each file host, each client of files, and a central server,

a database formed of an ordered blockchain block chain distributed on the private network and associated with a crypto-graphic write / read protocol for transactions carried out on the private network,

a secure transmission channel connecting said machines of the private network to each other,

a blockchain module hosted by each machine of the private network and configured to be able to read / write transactions in said blockchain so as to be able to interact with the other machines via the blockchain to authorize the transfer of the proprietary files of the hosting provider; files to the file client if predetermined transfer conditions are met and to track the use made by said file client of the transferred proprietary files,

an application module hosted by each machine of the private network and configured to be able to transfer files from the file hosting proprietor to the file client via the secure transmission channel if said predetermined conditions transfer are recorded in said blockchain.

A system according to the invention therefore comprises a network, said private network, which distributes a database consisting of an ordered block of blocks, and associated with a write / read protocol and cryptographic validation of transactions carried out. on the private network. Such a database is better known by its English name blockchain, which is used throughout.

A blockchain thus forms a transaction register, replicated on one or more machines of the private network interconnected by a peer-to-peer network. These machines are nodes of the private network and the communication between the nodes is encrypted and guarantees the identity of the sender and the recipient. When a node wants to add a new transaction to the registry, it proposes it to the network that forms a consensus to determine where and when that transaction is to be registered in the registry. This consensus is a block. In practice, a block groups several transactions.

According to the invention, the blockchain is used to list all the transactions between the different machines of the private network, and in particular between at least one machine that hosts proprietary files (the file host), at least one machine that requests the using a proprietary file (the file client) and a machine that controls the system (the central server). The blockchain ensures that the file has been sent by the file host and received by the file client. In addition, each use of the file by the file client is retranscribed in the blockchain, which makes it possible to identify and trace the use made of the transmitted proprietary file.

The particularity of the invention is also to use a secure transmission channel which connects the machines together and in particular the file host and the file client to ensure secure transfer as such proprietary computer files.

In other words, the blockchain and the blockchain modules of the different machines of the private network make it possible to organize the transfer of a proprietary computer file, to verify that the transfer has indeed taken place and to trace the use made of the file, once transferred, but the transfer as such is done through the secure transmission channel, which is controlled by the central server and the blockchain. It is only when the predetermined transfer conditions are recorded and read in the blockchain that the physical transfer of the file by the secure transmission channel takes place. Once the transfer is made, the blockchain records the confirmation of the transfer.

The operations of writing and reading in the blockchain by the machines of the private network are carried out by means of blockchain modules hosted by the machines and configured to interact with the blockchain.

According to a preferred embodiment, at least one module forms a minor module configured to validate each write / read transaction in the blockchain. In other words, it is this minor module that forms the consensus and validates the blocks and imposes them on all the machines in the network.

Throughout the text, and unless otherwise stated, the term "minor" refers to the action of "mining", that is to say the blockchain block validation operation and the synchronization of the different copies of the blockchain. the blockchain on the private network.

File transfer operations via the secure transmission channel are performed through application modules hosted by the machines.

Throughout the text, the term "module" denotes a software element, a subset of a software program that can be compiled separately, either for independent use, or to be assembled with other modules of a program, or a hardware element, or a combination of a hardware element and a software subprogram. Such a hardware element may comprise an application-specific integrated circuit (ASIC) or a programmable logic circuit (FPGA) for the English name Field- Programmable Gâte Array) or a specialized microprocessor circuit (better known by the acronym DSP for the English name Digital Signal Processor) or any equivalent hardware. In general, a module is therefore an element (software and / or hardware) that ensures a function.

The invention also relates to a secure transfer method and identified use (we also speak throughout the text traceable use) of computer files between at least one machine hosting proprietary computer files, said file host, and at least a machine requesting the reception and use of at least one of said proprietary computer files, said file client, said machines being connected to a network of machines, said private network, comprising at least one central server and a database formed an ordered blockchain block chain, distributed on the private network and associated with a write / read and cryptographic validation protocol for transactions carried out on said private network, said machines being further connected to each other by a transmission channel; secure transmission.

The method according to the invention comprises at least the following steps:

a file client requires the transfer of a proprietary file by a writing of a corresponding transaction in said blockchain,

said central server determines the validity of the request and informs, in the event of a valid request, said file host hosting said file requested by said file client,

said file host provides said file client with a key representative of the file address required by a write operation of a corresponding transaction in said blockchain,

said file client retrieves said proprietary file from said requested file address from said file host via said secure transmission channel,

said file client notifies the use of the proprietary file retrieved by writing a corresponding transaction in said blockchain, and uses said proprietary file with a dedicated application.

A method according to the invention is advantageously implemented by a system according to the invention and a system according to the invention advantageously implements a method according to the invention.

A method according to the invention thus makes it possible to organize and control the transfer of proprietary files between a proprietary file host and a file client.

Advantageously and according to the invention, the transaction write / read and cryptographic validation protocol implements at least one module, called a minor module, configured to be able to validate the write / read transactions in said blockchain.

According to this embodiment, each step of writing a transaction in the blockchain is followed by a step of validating the transaction by the minor module. This minor module can be hosted by a machine dedicated to the validation of transactions or can be hosted by a machine of the private network, for example by a file client, and / or by the central server. According to a variant of the invention, several minor modules are used in parallel to increase the computing power and the speed of implementation of the method.

As mentioned above, the term "minor" refers to the "mining" action, ie the blockchain block validation operation and the synchronization of the different copies of the blockchain on the private network. .

Advantageously and according to the invention, said write / read protocol and cryptographic validation of transactions performed on said private network of said blockchain is Ethereum® protocol implementing programmable entities, called smart contracts, each associated with a structure of data and methods for modifying these data, so that a writing of a transaction in said blockchain is a modification of at least one of said data associated with an intelligent contract obtained by executing one of said methods associated with a smart contract.

According to this advantageous variant, the use of Ethereum® protocol smart contracts makes it possible to initialize a contract in the blockchain for each proprietary computer file to be transferred from a file host. to a file client. The contract is initialized by the file client by executing a contract initialization method. This contract creation method provides an identification of the requested file, a file host address that holds the desired file, an amount in crypto currency, designated Ether in the Ethereum® protocol, and the number of copies desired. . Subsequently, all the exchanges between the file client and the host concerning this proprietary computer file are done by updating (or modifying) the corresponding contract.

Advantageously and according to the invention, said blockchain is initialized by providing in a first block, called block genesis, a predetermined list of identifiers, each identifier, said address, being determined from a private digital key and intended to designate a network machine.

According to this variant, each file client is assigned a predefined identifier in the genesis block of the blockchain. The blockchain module hosted by the file client is then set with the predefined identifier in the genesis block of the blockchain.

Advantageously and according to the invention, each private digital key associated with an address registered in said genesis block is obtained from the same predetermined root key and a predetermined derivation function.

According to this advantageous variant, the cryptographic security of the system and method according to the invention is based on a single predetermined root key. Thus, as soon as the private digital keys are generated and the identifiers of the machines are obtained, it is possible to delete the private digital keys and keep in a safe place only the root key. Indeed, in case of loss of identifiers, it is always possible with a system and a method according to the invention to find them by accessing the root key and the predetermined derivation function.

For example, each private numeric key is obtained from a 128-bit key and a derivation algorithm of the HKDF type for the English name Hashed Message Authentication Code (HMAC) Key Derivation Function.

Advantageously and according to the invention, each address is associated with a random amount greater than a predetermined threshold of crypto currency to allow each machine to perform transactions on said blockchain.

In particular, the Ethereum® protocol works with a cryptocurrency, or virtual currency, designated Ether, whose function is to pay for the execution of smart contracts, the operation of which can consume significant resources. In the Ethereum® protocol, the Ether is used to obtain "gas" (gasoline) to make the contracts work. The Ether also allows to reward the nodes that allow to validate the blocks of the blockchain.

To overcome this aspect inherent in the use of the Ethereum® protocol, but which is not applicable to the invention, the invention provides for allocating a large amount of Ether to each machine of the network so that they can always interact with the blockchain and never find without "gas".

Advantageously and according to the invention, at least said central server is a minor node of the private network configured to be able to validate each block of the blockchain.

Advantageously and according to the invention, said central server is also a host of proprietary files.

According to this variant, it is the central server that provides the proprietary files to the file clients. According to another variant, the file hosts are separate from the central server whose role is then limited to administering the blockchain.

Advantageously and according to the invention, said secure transmission channel implements a data exchange security protocol allowing authentication of each machine, and in particular the file client and said file host during the transfer of a proprietary file.

Such a protocol for securing data exchanges is for example the protocol known by the acronym TLS (for the English name Transport Loyer Security) or the protocol known by the acronym SFTP (for the English name Secure File Transfer Protocol).

Advantageously and according to the invention, said proprietary computer files are printing files intended for additive printers.

According to this advantageous variant, the system and the method according to the invention secure the transfer of printing files intended for 3D printers. A system and a method according to the invention therefore offer rights holders wishing to transfer a 3D computer file to an authorized user the security of the transfer and the traceability of the use of the transferred file. For example, a company wishing to provide a spare part to a remote customer can, thanks to the invention, transfer the digital file of the spare part without fear of the fraudulent use of the file by a third party and while being able to verify the use which is made of the file, by consulting the blockchain, which is unalterable.

According to this advantageous variant, the invention can also provide information on the quality of the part produced by the printer by reading the sensors of the 3D printer. In particular, each 3D printer has sensors to control and track the production of the piece. Reading sensor data and writing this data to the blockchain provides the file host with information about the quality of the part produced. This makes it possible, for example, to verify that the part produced satisfies predetermined criteria, for example in the case of a standard part having to meet certain specifications. The invention thus makes it possible, according to this variant, to remotely certify the quality of the parts produced by the additive printer by reading the sensors of the 3D printer and comparing the data supplied by these sensors with predetermined nominal values.

Advantageously and according to this variant, a file client that uses a print file received with an additive printer and that notifies it by writing a corresponding transaction in said blockchain includes a serial number associated with said product made from of said received print file.

Thus, the blockchain makes it possible to follow the manufacture of the parts and of List all the parts produced by using a proprietary file and associate each production with a serial number of the part.

According to other variants, at least one or more of the following information is recorded in the blockchain: serial number of the additive printer having printed the produced piece; Print settings used during printing information on the equipment used; information about the printer software. Of course, other information can also be recorded in the blockchain according to the needs of users of the invention.

Advantageously and according to another variant of the invention, the proprietary computer files are files for installing or updating proprietary software on a client file machine.

According to this variant, the invention makes it possible to securely transfer software or software updates to authorized users. In addition, the invention then makes it possible to follow the steps of installation or updating of the proprietary software and to track and trace the number of installations or updates made with the transferred file. All information is stored in the blockchain and can be controlled by the owner of the computer file updating the proprietary software.

This variant makes it possible, for example, to install software updates on motor vehicles and to determine the number of motor vehicles on which updates have been made.

The invention thus makes it possible to guarantee to right holders on a software or an update of a software that the file is used in accordance with the agreements provided between the different parties.

A method according to the invention can be implemented in the form of a sequence of instructions of a computer program. The method can also be implemented in hardware form or in a mixed hardware and software form. In the case where the invention is implemented partially or totally in the software form, the corresponding instruction sequence can be stored in a removable storage means, such as a diskette, a CD-ROM, a DVD-ROM, a USB key, etc., or a non-removable storage means, these various means being read partially or totally by a computer or a microprocessor.

The invention also relates to a computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, characterized in that it comprises program code instructions for the implementation of the method of secure transfer and traceable use of computer files according to the invention, when the program is executed on a computer.

The invention also relates to a computer readable storage means, totally or partially removable, storing a computer program comprising a set of instructions executable by a computer for implementing the method of secure transfer and traceable use of files. computer according to the invention.

The invention also relates to a system and a method characterized in combination by all or some of the features mentioned above or below.

5. List of figures

Other objects, features and advantages of the invention will become apparent on reading the following description given solely by way of non-limiting example and which refers to the appended figures in which:

FIG. 1 is a schematic view of a secure transfer system and identified use of computer files according to a first embodiment of the invention,

FIG. 2 is a schematic view of a secure transfer system and identified use of computer files according to an embodiment of the invention on which the various modules interacting with the blockchain and a 3D printer are represented,

FIG. 3 is a schematic view of a system and method of secure transfer and identified use of computer files according to another embodiment of the invention.

6. Detailed description of embodiments of the invention

FIG. 1 very schematically represents a system according to one embodiment of the invention comprising a network of machines, said private network 5, and grouping a machine hosting proprietary files, called file host 6, a machine requesting the use of a proprietary file, called client 7 files and a machine that controls the system, called central server 8.

Said file host 6, said file client 7 and the central server 8 are for example computers or, more generally, electronic machines operating by a sequential reading of a set of instructions.

The system according to the invention furthermore comprises a database formed of an ordered blockchain 9, distributed on the private network 5 and associated with a write / read and cryptographic validation protocol for transactions carried out on the private network 5. the private network between the different machines of the private network 5.

The system also includes a minor module 11 whose role is to validate the transactions of the blockchain 9. This minor module 11 can be an independent module or be integrated into one of the machines of the private network 5. The action of mining and the means for this mining are known to those skilled in the art and are not described here in detail.

In Figure 1, only one copy of the blockchain 9 has been shown for clarity, it being understood that in practice, the blockchain being distributed on the private network, each machine can host a copy of the blockchain 9.

The system according to the invention further comprises a dedicated channel, called a channel

10 of secure transmission, interconnecting the different machines of the private network, and in particular said file host 6 and said file client 7.

This secure transmission channel 10 preferably implements a secure data exchange protocol enabling authentication of each interacting part via this secure transmission channel. This protocol is for example the TLS protocol (for the English name Transport Rent Security) or the SFTP protocol (for Secure File Transfer Protocol) or any equivalent protocol.

According to the invention, the blockchain 9 is dedicated to the exchange of information for organizing and tracking the transfer of files from the file host 6 to the file client 7. The blockchain 9 also makes it possible to track the use of the file by the file client 7. The blockchain 9 also makes it possible to follow the exchanges of information between the central server 8 and the file host 6. The secure transmission channel 10 is used for the transfer of the files as such. It is also used to exchange information between the central server 8 and said file host 6.

Each machine further comprises a blockchain module 19 (shown in Figure 3 only), configured to read / write transactions in blockchain 9 so as to interact with other machines through the blockchain 9. This module 19 blockchain is for example a software layer configured to interact with the blockchain 9.

Each machine also comprises a blockchain application module 12 (shown in FIG. 3 only) configured to be able to interact on the secure transmission channel 10 and in particular to ensure the transfer of the proprietary files from the file host 6 to the file client 5. through the secure transmission channel 10.

According to a preferred embodiment of the invention, the protocol for writing / reading and crypto-graphical validation of transactions carried out on the private network of blockchain 9 is the Ethereum® protocol implementing programmable entities, called smart contracts, each associated with a data structure and methods for modifying that data, so that a write of a transaction in the blockchain 9 is a modification of at least one of the data associated with an intelligent contract obtained by an execution one of the methods associated with a smart contract.

In the following, the notion of writing / reading a transaction in the blockchain 9 refers indifferently to the execution of a data modification method associated with a smart contract (in the case where the Ethereum® protocol is used) or write / read as such of the transaction in blockchain 9 (in case another protocol is used).

In Figure 2, the file host and the central server are formed from the same machine. Throughout the following description with reference to Figure 2, this machine is designated central server 3 being understood that it also performs the function of file host. This hosting is shown schematically by a zone 32 for storing the proprietary files.

The system according to the embodiment of FIG. 2 thus comprises a central server 3 and a file client 2 which can interact with each other either by means of an Ethereum® protocol and the associated blockchain 9. or via a channel 42 of secure communication.

The central server 3 and the file client 2 each host, at a termination 38, respectively 28 IPC (acronym for the English name Inter-Process Communication) an Ethereum® client instance, for example the application pyethapp, geth or eth. In the following, this Ethereum® client instance is designated by the reference 25 for the client 2 of files and 35 for the central server 3.

According to this embodiment, the blockchain 9 is synchronized both by the file client 2 and by the central server 3. In addition, it is considered that at least the central server 3 or the file client 2 hosts a minor module. configured to validate the transactions performed on the blockchain 9. According to another variant, and as indicated above, the minor module may be an independent module hosted on a machine dedicated to the validation of transactions of the blockchain.

According to the embodiment of FIG. 2, the file client 2 hosts the Ethereum® client instance 25, an application in Javascript® 26 that uses the node.js software platform that is in interaction with the Ethereum® client instance. and an application 27, for example, implemented in python which is in interaction with an additive printer 22. The Ethereum® client instance 25 and the application in Javascript® 26 form, according to this embodiment, the blockchain module of the file client 2, and the application 27 forms the application module interacting with the printer 22.

The central server 3 hosts the Ethereum® client instance 35, an application in Javascript® 36 that uses the node.js software platform that is in interaction with the Ethereum® client instance 35 and an application 37 configured to be able to interact at a time. with the application in Javascript® 36 and with the storage area 32 of the proprietary files.

In this embodiment, the Ethereum® client instance 35 and the application in Javascript® 36 form the blockchain module of the central server 3, and the application 37 forms the application module in interaction with the storage area 32.

The method of securely transferring a file from the central server 3 to the file client 2 is obtained by the succession of the following steps:

- The file client 2 requires the download of a proprietary file. This request takes the form of a transaction in a blockchain 9 contract. This transaction is performed by the application 27 interacting with the additive printer 22 to the Ethereum® client instance through the application 26. Javascript ®. The Ethereum® client instance sends this request to the central server 3 or adds it directly to the blockchain 9 if the file client 2 hosts a minor module configured to validate the transactions. The Ethereum® protocol devp2p which is executed by both the file client 2 and the central server 3 synchronizes the transaction and adds a new block on each respective copy of the blockchain 9.

- The central server 3 determines the validity of the request, through the channel 42 of secure transmission, then performs a transaction in the contract of blockchain 9 to allow or not the request of the client based on this determination. If the request is valid, the central server 3 (which acts as a file host) provides a key representative of the address of the required file.

- The client 2 files makes regular queries of the contract of blockchain 9 to detect the return of the central server 3. As soon as it detects the key representative of the address of the file, it determines the address of the file from the representative key provided by the server in the blockchain 9. determination of the address is obtained for example by a predetermined mathematical function that combines said representative key provided by the file host, a predetermined public key and a signature of the required file (hashfile).

- The file client 2 starts downloading the file through the application 27 and the channel 42 secure transmission.

Once the file has been recovered, the file client 2 can notify the use in the blockchain 9 and use the recovered file.

FIG. 2 is only one possible embodiment for implementing the blockchain module and the application module in a machine of a system according to the invention. The skilled person is able to determine other software or hardware implementations of these modules. In addition, the software and hardware details of the Ethereum® protocol implementation are not described here in detail since the Ethereum® protocol provides tutorials for implementing the associated routines (see, for example, the website of the Ethereum® project at https://www.ethereum.org/).

FIG. 3 is a particular embodiment of the invention for the proprietary files dedicated to additive printers.

According to this particular embodiment, the system comprises a file host 16 and a central server 18. It further comprises a machine associated with a 3D printer, hereinafter referred to as a printing press 17. This printing works 17 acts as a file client insofar as it securely retrieves the proprietary file of the file host. The system also includes a machine requesting the printing of a proprietary file by the printing press 17, hereinafter referred to as the file client 17 '. The printer 17 and the client 17 'file form a particular file client consisting of two entities that can exchange through the blockchain. according to this particular embodiment, the proprietary computer files are therefore 3D printing files. A system according to the embodiment of FIG. 3 not only makes it possible to secure the transfer of a file from a file server to a file client, but it also makes it possible to provide the client with files with information on the quality. printing the part corresponding to the file server by sharing a print log as explained below.

In FIG. 3, the dashed arrows represent steps of the method according to the invention implementing the blockchain 9 and the dotted arrows represent steps of the method according to the invention implementing the secure transmission channel 10. The steps E1 to E10, concentrated on the right-hand part of the figure, are the steps implemented to transfer a proprietary file from the file host 16 to the printing press 17. Steps Ε to Ε1, concentrated on the left-hand side of the figure are the steps implemented to use the computer file by the file client 17 'which is characterized by the printing of a 3D part by the printing press 17.

In Figure 3, the minor module 11 is not shown for clarity. This module is hosted by the central server 18. Also, in the description of FIG. 3, the validation of the transactions is carried out by the central server 18. According to other embodiments, the validation can be carried out by another module of FIG. another node configured to mine transactions.

The steps necessary for the printer 17 to retrieve a proprietary file from the file host 16 are as follows:

El step: the printing press 17 requires the transfer of a proprietary file by writing a transaction in the blockchain 9.

This transaction consists, according to the preferred embodiment of the invention, of executing a method associated with an intelligent contract of the blockchain 9. The central server 18, which regularly polls the state of the smart contract, acknowledges receipt of the request by writing the message. corresponding transaction in the blockchain 9. According to another variant, the central server 18 receives a request through the secure transmission channel 10 so that it does not have to regularly check the state of the blockchain contract. It then acknowledges receipt of this request by writing a transaction in the blockchain.

Step E2: The central server 18 informs the host 16 of files via the secure transmission channel 10 that a request has been issued by the printing house 17. According to a variant, the file host 16 and the server 18 central office are one and the same machine, in which case step E2 is not necessary. According to another variant, the information passes through the blockchain 9, in which case the file host 16 must have the same functionality as the central server.

Step E3: The file host 16 writes a transaction in blockchain 9 by updating intelligent contract data and providing a key representative of a unique and valid address only once of the required file. In parallel, said file host 16 creates the corresponding uniform resource locator (better known by the acronym URL for Uniform Resource Locator) which is accessible only by the print shop 17. The transaction is validated by the central server 18 .

Step E4: The printing house 17 scrutinizes the state of the smart contract. As soon as the transaction has been validated by the central server 18 and the key representative of the address of the file is detected, the printer determines the address of the file.

Step E5: The printer 17 retrieves the file from the file host 16 via the secure transmission channel 10.

Step E6: The printing press 17 confirms the beginning of the downloading of the file by the writing of a transaction in the blockchain 9, which is validated by the central server 18.

Step E7: The file host 16 confirms the start of the download by writing a transaction in blockchain 9, which is validated by the central server 18.

- Step E8: The printer 17 completes the download of the file from the file host 16.

- Step E9: The printer 17 updates the status of the smart contract and confirms that the file has been recovered. The corresponding transaction is validated by the central server 18.

Step E10: The file hosting server 16 confirms the end of the transmission of the file and the central server 18 validates the transaction.

According to the embodiment of FIG. 3, once the file has been recovered by the printer 17, the client 17 'of files must then start the printing operation of the file. To do this, the following steps are implemented:

- Step El ': The file client 17' sends a request to print the file by the print shop 17. This request takes the form of a transaction in the blockchain 9 which is validated by the central server 18.

Step E2 ': The central server 18 detects the request in the blockchain 9 and notifies it to the printing press 17 via the secure transmission channel 10. According to another embodiment, the request is notified by the secure transmission channel 10 and the server 18 verifies its validity by reading the transaction in the blockchain.

- Step E3 ': The printing office notifies the validity of the request by writing a transaction in blockchain 9, which is validated by the central server 18.

Step E4 ': The client 17' reads the response by reading a transaction in the blockchain 9 and creates a URL.

Step E5 ': The client 17' confirms the beginning of the printing of the file.

Step E6 ': Client 17' performs a transaction in blockchain 9 to confirm the start of printing. The transaction is validated by the central server 18. - Step E7 ': The printing house 17 reads the confirmation transaction in the blockchain 9 and acknowledges receipt by writing a corresponding transaction in the blockchain 9. The transaction is validated by the central server 18.

Step E8 ': When the printing house 17 has finished printing the file, it performs a transaction in the blockchain 9 to provide a key representative of a download URL of a print log. This print log (better known as the print log) provides print quality data. The printing office 17 then creates the corresponding URL. The transaction is validated by the central server 18.

Step E9 ': The central server 18 reads the key representative of the URL in the blockchain 9 and determines the corresponding address.

Step E10 ': The central server 18 begins downloading the print log and notifies it in the blockchain 9 by writing a transaction. The transaction is validated by the central server 18 (or by any module configured to undermine the transactions).

Step Ε1: When the central server 18 has finished downloading the print log, it notifies it in the blockchain by writing a corresponding transaction. The transaction is validated by the central server 18 (or by any module configured to undermine the transactions).

A system and method according to this embodiment thus makes it possible not only to secure the transfer of a proprietary file of a proprietary file host to an additive printer, to identify and trace the use made of the proprietary file, and also to provide information on the quality of the printing of the piece.

A system according to the invention is not limited solely to the described embodiments. In particular, a system and a method according to the invention can be implemented for other applications than those described in connection with additive printing. In general, the invention can be implemented works for all applications requiring secure transfer and traceable use of proprietary computer files.

Claims

\. A method of secure transfer and identified use of computer files between at least one machine hosting proprietary computer files, said host (6; 16; 3) files, and at least one machine requesting the receipt and use of least one of said proprietary computer files, said client (7; 17, 17 '; 2) files, said machines being connected to a network of machines, said network (5) private, and comprising at least one central server (8; ) and a database formed of an ordered blockchain (9), distributed on the private network (5) and associated with a write / read protocol and crypto-graphic validation of transactions carried out on the network said machines being further connected to each other by a secure transmission channel (10; 42), said method comprising at least the following steps:

a client (7; 17, 17 '; 2) of files requires the transfer of a proprietary file by a writing of a corresponding transaction in said blockchain (9),

said central server (8; 18) determines the validity of the request and informs, in case of valid request, said host (6; 16; 3) of files hosting said file requested by said client (7; 17, 17 '; 2 ) files,

said host (6; 16; 3) of files provides said file client with a key representative of the file address required by a write operation of a corresponding transaction in said blockchain (9),

said client (7; 17,17; 2) of files retrieves said proprietary file from said address of the requested file from the host (6; 16; 3) of files through said transmission channel (10; 42) secured,

said client (7; 17, 17 '; 2) of files notifies the use of the file owner retrieved by writing a corresponding transaction in said blockchain (9), and uses said proprietary file with a dedicated application.

2. Method according to claim 1, characterized in that said transaction write / read and crypto graphical validation protocol implements at least one module, said minor module (11), configured to be able to validate the write transactions. / reading in said blockchain (9).

3. Method according to one of claims 1 or 2, characterized in that said write / read protocol and crypto graphical validation of transactions performed on said network (5) private blockchain (9) is the Ethereum® protocol implementing programmable entities, called intelligent contracts, each associated with a data structure and methods for modifying the data, so that a transaction write in said blockchain (9) is a modification of at least one of said data associated with an intelligent contract obtained by executing one of said methods associated with a smart contract.

4. Method according to one of claims 1 to 3, characterized in that said blockchain (9) is initialized by providing in a first block, said block genesis, a predetermined list of identifiers, each identifier, said address, being determined from a private digital key and intended to designate a network machine.

5. Method according to claim 4, characterized in that each private digital key associated with an address registered in said genesis block is obtained from a same predetermined root key and a predetermined derivation function.

6. Method according to one of claims 4 or 5, characterized in that each address is associated with a random amount greater than a predetermined threshold of cryptocurrency to allow each machine to perform transactions on said blockchain.

7. Method according to one of claims 4 to 6, characterized in that at least one minor module (11) crypto graphical validation of transactions in said blockchain (9) is hosted by said central server (8; 18).

8. Method according to one of claims 1 to 7, characterized in that said host (6; 16; 3) files and said central server (8; 18) are a single machine.

9. Method according to one of claims 1 to 8, characterized in that said channel (10; 42) of secure transmission implements a secure data exchange protocol for authentication of each transmitting machine and receiving data.

10. Method according to one of claims 1 to 9, characterized in that said proprietary computer files are printing files for additive printers.

The method of claim 10, wherein said file client that uses a print file retrieved with an additive printer and notifies it by writing a corresponding transaction in said blockchain (9) includes a serial number associated with said product made from said print file.

12. Method according to one of claims 1 to 9, characterized in that said proprietary computer files are installation files or updating proprietary software.

13. System for secure transfer and identified use of computer files between at least one machine hosting said proprietary computer files, said host (6; 16; 3) of files, and at least one machine requesting the reception and use of at least one of said proprietary computer files, said client (7; 17, 17 '; 2) files, said system comprising:

a network of machines, said private network (5), comprising each host (6; 16; 3) of files, each client (7; 17, 17 '; 2) of files, and said central server (8; 18),

a database formed of an ordered blockchain (9), distributed on the private network and associated with a crypto-graphic read / write and read protocol; transactions carried out on said private network (5),

a secure transmission channel (10; 42) connecting said machines to each other,

a blockchain module (19) hosted by each machine of the private network and configured to read / write transactions in said blockchain (9) so as to interact with the other machines through the blockchain (9) to allow the transfer files hosting the host (8; 18; 3) files to the client (7; 17; 17 '; 2) files if predetermined transfer conditions are met and to track the use made by said client ( 7; 17, 17 '; 2) files transferred proprietary files,

an application module (12) hosted by each machine of the private network and configured to be able to transfer the proprietary files of the host (8; 18; 3) of files to the client (7;

17, 17 '; 2) files through the secure transmission channel (10; 42) if said predetermined transfer conditions are registered and validated in said blockchain (9).

14. Computer program product downloadable from a communication network and / or recorded on a computer readable medium and / or executable by a processor, characterized in that it comprises program code instructions for the implementation of the method of secure transfer and identified use of computer files, according to one of claims 1 to 12, when the program is run on a computer.

15. Computer-readable storage medium, totally or partially removable, storing a computer program comprising a set of instructions executable by a computer for implementing the method of secure transfer and identified use of computer files, according to the one of claims 1 to 12.