IMPROVED METHOD FOR TRANSMITTING CONTENT USING A QUANTUM KEY DISTRIBUTION NETWORK.

Abstract

The invention relates to a method for transmitting a content (A) in a communication network (N) comprising a quantum distribution network (QKDN) of keys called quantum keys (Knj), the communication network comprising a key manager device (KM) connected to transmission nodes (N1, N2, N3, N4, N5) and connected to said quantum distribution network (QKDN) of keys, said transmission nodes (N1, N2, N3, N4, N5) being able to communicate in the communication network and to transmit and receive quantum keys (Knj) in said quantum distribution network of keys, said method comprising sending and receiving control messages from and to said control plane manager (CP) to organize the transfer of said content (A) in said communication network (N), which messages comprise condensates for identifying quantum keys.The invention further relates to a control plane (CP) manager device configured to execute said method. Fig. 3.

Description

Title of the invention: IMPROVED METHOD FOR TRANSMITTING CONTENT USING A QUANTUM KEY DISTRIBUTION NETWORK. Technical field

[0001] The present invention relates to a method for securely transmitting content between two transmission nodes of a communication network comprising a quantum key distribution network and a control plane manager device responsible for sequencing operations useful for transmitting the content in the network. At least one embodiment relates to an improved transmission of an encryption key between two transmission nodes of a communication network. The invention relates more particularly to reducing the attack surface during such content transmission. STATE OF THE PRIOR ART

[0002] It is known to securely transfer an encryption key, also commonly called a cryptographic key, between two transmission nodes of a communication network, using a quantum key distribution network. Such an encryption key transfer, which allows it to be shared between two participants, namely its sender and its recipient, aims to then operate encrypted communications between these two participants. A quantum key distribution network is considered to be "quantum" insofar as it manipulates keys called quantum keys, the difficulty of interception of which is based not on a supposed computational (mathematical) difficulty of a problem (as is the case for many cryptographic processes) but on fundamental properties of quantum physics applied to photon-type particles.The implementation of a quantum key exchange is based on the ability to generate random quantum objects, to measure these quantum objects, and then to transmit them over sufficient distances, for example between two transmission nodes of a communication network, at the level of a so-called quantum communication layer using optical means. The security of quantum key exchange protocols (or quantum key exchange) is based on the assumption that, according to a so-called no-cloning theorem, an adversary cannot learn the state of a particle before its measurement and that a measurement of the state of a quantum particle alters its state. This security is therefore based on a property of quantum physics.

[0003] Methods for sharing a symmetric encryption key between a sender and a recipient connected to the same communication network use nodes of quantum transmissions each configured to operate transmissions in a classical communication layer, for example according to an IP protocol, and to operate only transmissions of quantum keys in an optical quantum communication layer, called the quantum layer, by using a key management device connected to the transmission nodes.According to these methods, the key management device used receives intermediate results of a quantum key derivation function, which function has particular properties, from a source transmission node (sender of the encryption key to be shared) and from one or more intermediate transmission nodes, between which quantum keys circulate, and then transmits to a destination transmission node (receiver of the encryption key to be shared) a final result of operations executed by the key management device, from which the destination transmission node can retrieve the encryption key to be shared, without the latter circulating in the communication network and without it being possible to retrieve it from an intermediate result transmitted in the communication network.Such an encryption key sharing method is described in the description part of the present application, in relation to [Fig.l] and [Fig.2], in an example according to which a key derivation function KDF is the so-called exclusive or function, still commonly called xor and whose operator is here represented by the symbol "®", applied to two data called input data. Although this principle of key transfer between a source transmission node and a destination transmission node is known, it is not used more widely for the transmission of any content through a communication network, such as for example a mesh network, since there is no control protocol dedicated to the implementation of such a transfer via a plurality of transmission nodes operating in a communication network and being further included in a quantum key distribution network.There is also a constant need to increase the security of content transfers in such a communication network and the situation can be improved. Statement of the invention

[0004] An object of the present invention is to reduce the attack surface of a secure transmission of content in a communication network by increasing the level of transmission security offered by encryption key sharing methods using a quantum key distribution network.

[0005] To this end, a method is proposed for transmitting content between two transmission nodes of a communication network comprising these two transmission nodes and at least one other transmission node called an intermediate transmission node, the transmission nodes being further included in a network of dis quantum distribution of keys called quantum keys, the communication network comprising a key management device connected to said transmission nodes and connected to said quantum key distribution network, the transmission nodes each comprising a plurality of communication interfaces for communicating in the communication network and a plurality of quantum key transmission interfaces for transmitting and receiving said quantum keys in said quantum key distribution network, and the transmission nodes being further configured to each operate a key derivation function and address the result thereof to said key management device, and to each operate a key extraction function from information received from the key management device and from a received quantum key, said communication network further comprising a control plane management device configured to execute the steps:

[0006] - receive, from one, said source node, among said two transmission nodes, a request message for transmission of said content to the other, called the destination node, among said two transmission nodes, said request message comprising an identifier of said destination node,

[0007] - obtain a route determined as passing through said at least one inter-node transmission mediator or by a series of intermediate transmission nodes between said source node and said destination node, and a transmission service identifier of said content associated with said route,

[0008] - transmitting and receiving control messages to and from said nodes of transmission and to said key management device, capable of generating key transmissions between pairs of nodes among said nodes, defined according to said route determined in relation to said transmission service identifier, the transmission method being such that, when a control message sent to or from said control plane manager comprises an identifier of a quantum key transmitted or to be transmitted between two transmission nodes, this identifier is a condensate of said quantum key transmitted or to be transmitted.

[0009] Thus, it is advantageously possible to transmit any content end-to-end, between a source transmission node and a destination transmission node of a communication network comprising a quantum key distribution network, thanks to simple and centralized management, and by offering an increased level of security insofar as the quantum key identifiers transmitted between the transmission nodes and the control plane management device are each in the form of a condensate of a quantum key.

[0010] The method according to the invention may also include the following characteristics, considered alone or in combination: - sending and receiving control messages includes: • send, to said key manager, a control message including said transmission service identifier, • send, to said source node, a control message comprising at least said service identifier and an identifier of a quantum key transmission interface, • receive, from said source node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said transmission service identifier of said content, • send, to each intermediate transmission node, a control message comprising at least said service identifier, a quantum key reception interface identifier and a quantum key identifier received or to be received in the form of a digest of said quantum key via said quantum key reception interface, and a quantum key transmission interface identifier, • receive, from each intermediate transmission node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said transmission service identifier of said content, • send, to said key management device, a control message comprising an end of sequence identifier and an identifier of the destination node, and, • send, to said recipient node, a control message comprising at least said service identifier, a quantum key reception interface identifier and a quantum key identifier in the form of a digest of said quantum key received or to be received via said quantum key reception interface. - sending the control message to said source node and sending a control message to each of said intermediate nodes further comprises a unique sequence identifier of a sequence of unique sequence identifiers determined for said transmission of said content in relation to said service identifier, each unique sequence identifier of said sequence of unique sequence identifiers being capable of determining the rank of a sequence with which it is associated in a sequence of sequences defined in relation to said transmission of said content.

[0011] Advantageously, it is thus possible to use a non-commutative key derivation KDF function and to carry out rerouting during transmission, in the event of a malfunction. operation of a link in the communication network. - the key derivation function has properties according to which said function applies to two data, called input data, and that the result of said function applied to said two data is zero when said two data are equal to each other and that the result of said function applied to said two data is equal to one of said two data when the other of said two data is zero. - the key derivation function is a so-called “exclusive or” function and the said two data have the form of binary words of identical sizes.

[0012] The invention also relates to a communication network comprising a control plane manager device configured to operate a transmission control of a content between two transmission nodes of said communication network further comprising at least one other transmission node called intermediate transmission node, said transmission nodes being further included in a quantum key distribution network called quantum keys, the communication network comprising a key manager device connected to said transmission nodes and connected to said quantum key distribution network, said transmission nodes each comprising a plurality of communication interfaces for communicating in the communication network and a plurality of quantum key transmission interfaces for transmitting and receiving said quantum keys in said quantum key distribution network,and said transmission nodes being further configured to each operate a key derivation function and address the result thereof to said key management device and to each operate a key extraction function from information received from said key management device and from a quantum key, said communication network further comprising a control plane management device, said control plane management device comprising electrical and electronic circuitry configured to: ,

[0013] - receive, from one, said source node, among said two transmission nodes, a request message for transmission of said content to the other, called the destination node, among said two transmission nodes, said request message comprising an identifier of said destination node,

[0014] - obtain a route determined as passing through said at least one inter-node transmission mediator or by a series of intermediate transmission nodes between said source node and said destination node, and a transmission service identifier of said content associated with said route,

[0015] - transmitting and receiving control messages to and from said nodes of transmission or to said key management device, capable of generating trans- quantum key missions between pairs of nodes among said nodes, defined according to said route determined in relation to said transmission service identifier,

[0016] the communication network being configured such that, when a control message sent to or from the control plane manager comprises an identifier of a quantum key transmitted or to be transmitted between two transmission nodes, this identifier is a condensate of the quantum key transmitted or to be transmitted.

[0017] The control plane management device according to the invention may also include the following characteristics, considered alone or in combination:

[0018] - The control plane manager device further comprises circuitry electronics configured for: • send, to said source node, a control message comprising at least said service identifier, an identifier of a quantum key transmission interface, • receive, from said source node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said transmission service identifier of said content, • send, to each intermediate transmission node, a control message comprising at least said service identifier, a quantum key reception interface identifier and a quantum key identifier in the form of a digest of said quantum key received or to be received via said quantum key reception interface, a quantum key transmission interface identifier, • receive, from each intermediate transmission node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said transmission service identifier of said content, • send, to said key management device, a control message comprising an end of sequence identifier and an identifier of the destination node, and, • send, to said recipient node, a control message comprising at least said service identifier, a quantum key reception interface identifier and a quantum key identifier in the form of a digest of said quantum key received or to be received via said quantum key reception interface.

[0019] - The control plane manager device further comprises circuitry electronics configured to insert into the control message to said source node and into the control message to each of said intermediate nodes an identifier unique sequence identifier of a sequence of unique sequence identifiers determined for said transmission of said content in relation to said service identifier, each unique sequence identifier of said sequence of unique sequence identifiers being capable of determining the rank of a sequence with which it is associated in a sequence of sequences defined in relation to said transmission of said content.

[0020] The invention further relates to a communication network comprising a plurality of transmission nodes, a key management device, as well as a control plane management device as previously described, in which each of the transmission nodes is further configured to: - sending a message to the key management device, said message addressed to said key management device comprising a key derivation function result, said service identifier, and a sequence identifier of a sequence of unique sequence identifiers determined for said transmission of said content in relation to said service identifier, each unique sequence identifier of said sequence of unique sequence identifiers being capable of determining the rank of a sequence with which it is associated in a sequence of sequences defined in relation to said transmission of said content, and - receiving from said key management device a message comprising said service identifier and a key derivation function result.

[0021] The invention also relates to a transmission node in a quantum key distribution network, the transmission node being configured to operate, from at least one quantum key, a key derivation function or a key extraction function, the transmission node comprising means for generating, storing, receiving and transmitting a quantum key, the transmission node further comprising means for receiving and transmitting control messages capable of operating, in combination with a key management device and a control plane management device, a method for transmitting content in a communication network comprising the transmission node, and the transmission node being such that it comprises electronic and / or computer circuitry configured for, when sending a quantum key from the transmission node is required: - operate a hash function having as input variable said quantum key transmitted or to be transmitted, - transmit a first digest, the result of said hash function applied to said quantum key transmitted or to be transmitted, the first digest operating as an identifier of the quantum key according to the content transmission method,

[0022] and for, from a quantum key received by the transmission node: - operate said hash function having as input variable the received quantum key to obtain a second condensate and record in a memory the second condensate in association with said received quantum key, - receive the first condensate operating as a quantum key identifier, and, - identify a received quantum key, by comparing the first condensate with a list of condensates comprising the second determined condensate.

[0023] The invention also relates to a computer program product comprising program code instructions for executing the steps of a method as previously described, when this program is executed by a processor of a control plane management device.

[0024] Finally, the invention also relates to a storage medium comprising a computer program product as mentioned above. Brief description of the drawings

[0025] The above-mentioned features of the invention, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings:

[0026] [Fig.l] schematically illustrates a transmission node of a communication network comprising a communication module via an IP network and a quantum key communication module;

[0027] [Fig.2] schematically illustrates a transmission of content between two transmission nodes of a communication network, via an intermediate communication node, according to the prior art;

[0028] [Fig.3] schematically illustrates a communication network comprising transmission nodes, a key management device and a control plane management device, according to one embodiment;

[0029] [Fig.4] schematically illustrates a quantum key distribution network included in the communication network already illustrated in [Fig.3], according to one embodiment;

[0030] [Fig.5] illustrates an example of internal architecture of a transmission node as described in relation to [Fig.l], [Fig.2] and [Fig.3], according to one embodiment;

[0031] [Fig.6] illustrates an example of internal architecture of a key management device as described in relation to [Fig.1], [Fig.2] and [Fig.3], according to one embodiment;

[0032] [Fig.7] illustrates an example of internal architecture of a control plane manager device as described in relation to [Fig.3] and [Fig.4], according to one embodiment;

[0033] [Fig.8] is a diagram illustrating a sequencing of operations implemented according to a method of transmitting content A between two transmission nodes of a communication network, via an intermediate communication node, according to one embodiment;

[0034] [Fig.9] is a diagram illustrating a sequencing of operations implemented according to a method of transmitting content A between two transmission nodes of a communication network, via three intermediate transmission nodes, according to one embodiment;

[0035] [Fig. 10] is a schematic representation of a transmission node of the communication network already described in [Fig.3];

[0036] [Fig. 11] is a flowchart illustrating a method of transmitting a content A between two transmission nodes of a communication network, via at least one intermediate communication node, executed in a control plane manager device according to one embodiment; and,

[0037] [Fig. 12] is a diagram illustrating a quantum key transmission between two transmission nodes of a communication network comprising a transmission of a quantum key identifier in the form of a quantum key hash, according to one embodiment.

[0038] DETAILED DESCRIPTION OF EMBODIMENTS

[0039] [Fig.l] schematically illustrates a transmission node NI configured to communicate in an IP (Internet Protocol) type communication network and to participate in a quantum key distribution network adapted to the transmission of quantum keys between two adjacent transmission nodes. The terms "adjacent transmission nodes" here designate indifferently a physical proximity or a logical proximity and correspond to two transmission nodes capable of carrying out transmissions between them without the transmitted data passing via an intermediate communication node. The transmission node NI can be integrated into any communication equipment, such as a router or an encryptor, for example. The transmission node NI comprises a communication module IPN1 configured to carry out communications in an IP type communication network.The IPN1 communication module comprises communication interfaces each capable of carrying out data transmissions in an IP type communication network. According to the example described, the NI transmission node comprises an IPI communication interface, an IP2 communication interface and an IP3 communication interface, all capable of carrying out data transmissions via an IP type communication network. The NI transmission node further comprises a QN1 communication module called a quantum module (of a type usually called a “QKDnode”), configured for the management. generation, storage and transmission of quantum keys. The quantum module QN1 comprises interfaces Q1, Q2, Q3 and Q4, called quantum interfaces, each configured to operate transmissions of quantum keys via optical transmission means. The quantum interfaces Q1, Q2, Q3 and Q4 are each provided in particular to transmit quantum keys to similar interfaces (configured for reception) of a similar transmission node, for example, to an adjacent node of the same communication network operating quantum node functions of the QKDnode type in a quantum key distribution network. The quantum interfaces Q1, Q2, Q3 and Q4 are furthermore each configured to receive quantum keys from an external source, via optical transmission means, for example, from an adjacent node of the same communication network operating quantum node functions QKDnode in a quantum key distribution network.According to one embodiment, the optical means are configured for the transmission of quantum keys through optical fibers or via “laser” technology communication means commonly called “Laser on the air”. Each of the quantum interfaces Q1, Q2, Q3 and Q4 comprises a quantum key storage buffer supplied with quantum keys from a QKB quantum key generator. Thus, the quantum interface Q1 comprises a quantum key storage buffer B1; the quantum interface Q2 comprises a quantum key storage buffer B2; the quantum interface Q3 comprises a quantum key storage buffer B3 and the quantum interface Q4 comprises a quantum key storage buffer B4.According to an exemplary embodiment, the QKB quantum key generator feeds each of the storage buffer memories so that a quantum key can be delivered on a determined quantum interface when a quantum key transmission is necessary. For example, the QKB quantum key generator fills each of the buffer memories with the same predefined number of quantum keys before a first quantum key transmission takes place, then maintains a filling level in each of the quantum key buffer memories B1, B2, B3 and B4 over the course of the quantum key transmissions that have been carried out by the quantum module QN1. According to an embodiment, the quantum keys generated and stored in the quantum key storage buffer memories have a predefined fixed size (width).According to an alternative embodiment, the size of a quantum key can be adjusted according to operating parameters which are themselves adjusted according to specific needs during use, possibly dynamically. According to one embodiment, the communication module IPN1 and the quantum module QN1 are controlled by the same control unit configured to synchronize their operation. Thus, by . example, a control message can be received by the transmission node NI via the communication module IPN1 and can be interpreted by the control unit of the transmission node NI for the purpose of generating a transmission of a quantum key via one of the quantum interfaces Q1, Q2, Q3 and Q4. According to an alternative embodiment, quantum keys are generated towards each of the quantum interfaces Q1, Q2, Q3 and Q4 and are transmitted towards an adjacent transmission node only when necessary, under the control of a dedicated control unit of the transmission node NI.

[0040] An example of the internal architecture of the internal control unit of the transmission node NI is described further in relation to [Fig.5].

[0041] The representation of the transmission node NI in [Fig.l] does not show all of these components, for the sake of simplification. For example, the transmission node NI comprises an electronic control unit with microprocessor(s), not shown in [Fig.l] since such implementation details of the transmission node NI are not useful for a good understanding of the invention. According to a similar principle, the implementation details of the QKB quantum key generator are not developed here. The QKB quantum key generator of the transmission node NI uses a quantum random generator then a QKD (Quantum Key Distribution) logic key generation system coupled with an optical encoding of the keys capable of then circulating on an optical fiber.According to an exemplary embodiment, the QKB quantum key generator uses a cutting of an optical beam of a continuous laser diode with an electro-optical modulator or by electrically pulsing a diode. According to the example shown in [Fig.l], the communication module IPN1 of the transmission node NI comprises three communication interfaces IPI, IP2 and IP3 and the quantum module QN1 of the communication node IPN1 comprises four quantum interfaces Q1, Q2, Q3 and Q4. This example is however not limiting and a similar communication node may comprise a different number of communication interfaces as well as a different number of quantum interfaces.

[0042] The transmission node NI is further configured to be able to transmit to an external device, such as for example a key management device, a result of a KDF key derivation function applied to two data called input data. For example, the transmission node NI is configured to receive a first data item via one of its communication interfaces IPI, IP2 or IP3 and to then operate a KDF key derivation function, such as for example the “exclusive or” function also commonly called xor function and whose operator is often represented by the symbol “®”, between this first data item and a second input data item, and to then address the result of this key derivation function applied to the two input data items to a third-party device, via one of the interfaces of IPI, IP2 and IP3 communication. According to one example, the first input data is a quantum key received via optical transmission means, from an adjacent transmission node connected to the NI node. According to another example, the first input data is data received from an application layer, such as content to be transmitted in a communication network comprising the NI transmission node, or a fragment of such content.

[0043] The transmission node NI may be associated with other similar transmission nodes to form a communication network, for example a mesh or partially meshed communication network.

[0044] In the present description, a quantum key generated by the transmission node NI and transmitted via the quantum interface Q1 of this transmission node NI is called kl 1 ; a quantum key generated by the node NI and transmitted via the quantum interface Q2 of this transmission node NI is called kl2, and so on. More generally, a quantum key generated by a transmission node Nn and transmitted via an interface Qj of this transmission node Nn is called quantum key Knj. According to one embodiment, each quantum key transmitted by the transmission node NI, or more broadly by a transmission node similar to the transmission node NI, is accompanied by a quantum key identifier which makes it possible to refer to this quantum key by means of this identifier. [Fig. 10] is a simplified schematic representation of a transmission node as already described in [Fig.l] according to which the node is referenced by a transmission node identifier (here NI) and is characterized by the fact that it comprises IP type communication interfaces (here IPI, IP2, and IP3 according to the example described) and quantum key transmission interfaces (here Ql, Q2, Q3 and Q4 according to the example described). In the following description, examples of transmission of content in a communication network N are developed. For the purposes of simplification, the communication network N described later comprises, in addition to the transmission node NI represented here, four transmission nodes N2, N3, N4 and N5 similar to the transmission node NI and each comprising IP type communication interfaces and quantum key transmission interfaces Q capable of carrying out communications and quantum key transmissions according to the links represented and described between the different transmission nodes.In the following description, the details of the IP interfaces and the Q quantum interfaces are no longer shown, but the links between two quantum interfaces are illustrated by dotted lines and the links between IP interfaces are illustrated by solid lines.

[0045] [Fig.2] illustrates an example of transmission of a content A through a communication network N comprising a quantum distribution network QKDN, according to the prior art. The network N, comprises the transmission node NI previously described in relation to [Fig.l] as well as transmission nodes N2, N3, N4 and N5 similar to the transmission nodes NI, except that the number of communication interfaces in the network N and quantum interfaces of each of the transmission nodes N2, N3, N4 and N5 may vary. According to one embodiment, the network N and the quantum key distribution network QKDN are mesh networks in which communication links exist respectively established between the transmission nodes NI and N2, between the transmission nodes N2 and N3, between the transmission nodes NI and N3, between the transmission nodes NI and N4, between the transmission nodes N4 and N5, between the transmission nodes N5 and N3, as well as between the transmission nodes N2 and N4. Equivalent links exist with regard to the quantum key distribution layer called "quantum layer" between quantum interfaces of these nodes, for the same inter-node links.In other words, a quantum key distribution link exists between the transmission nodes NI and N2, another quantum key distribution link exists between the transmission nodes N2 and N3, and so on for the pairs of nodes NI and N3, NI and N4, N4 and N5, N5 and N3, and finally N4 and N2. Obviously, this example of interconnection of the nodes NI, N2, N3, N4 and N5 for the “classical” communication layer according to an IP protocol, and for the quantum layer, is not limiting and the quantum mesh can use interconnection links different from those established in the quantum layer. According to the example of transmission of the content A illustrated in relation to [Fig. 2], the transmission node NI receives, from an application or an application module capable of communicating with it, a message comprising a request for transmission of a content A, to a destination transmission node.This message is received via one of the communication interfaces of the transmission node NI. According to the example described, the destination transmission node is the transmission node N3. The transmission node NI having received the request to transmit the content A is called the “source transmission node”. According to a non-limiting example, the content A to be transmitted is a symmetric encryption key to be used for subsequent secure sharing of content between the transmission nodes NI and N3 (source and destination). A transfer of content between the transmission nodes NI and N3 can be secured by a prior exchange, itself highly secure, of an encryption key using the operating mode described below: i.the transmission node NI receives the content A, accompanied by a request message for transmission of this content, and operates a key derivation KDF function using the xor function as a key derivation KDF function applied to two input data of the function which are the content A received, on the one hand, and a quantum key kl 1 generated by the transmission node NI and further delivered to the transmission node N2 via the quantum link between . the transmission nodes NI and N2.

[0046] A result resl of the key derivation function is then sent by the transmission node NI to a key management device KM, via a communication link established between the transmission node NI and the key management device KM. i. The transmission node N2 receives the quantum key kl 1 transmitted by the transmission node NI via one of its quantum interfaces and operates a key derivation function using the xor function as a key derivation KDF function applied to two input data of the function, namely the quantum key kl 1 received, on the one hand, and a quantum key k21 generated by the transmission node N2 (and further delivered to the destination transmission node N3 via the quantum link between the transmission nodes N2 and N3). A result res2 of the key derivation KDF function is then sent by the transmission node N2 to the key manager KM, via a communication link established between the transmission node N2 and the key manager device KM. ii. The key management device KM performs an xor function between the result resl received from the transmission node NI and the result res2 received from the transmission node N2 and transmits a result res3 to the destination transmission node N3, which can then retrieve the content A from the quantum key k21 received and transmitted by the transmission node N2.

[0047] An example of the internal architecture of the KM key management device is described further in relation to [Fig.6].

[0048] According to this example, it is considered that the content A (here an encryption key intended to secure subsequent exchanges) is transferred between the source transmission node NI and the destination transmission node N3 via the transmission node N2, considered here as an intermediate transmission node, used jointly in combination with the key management device KM, so that the content A never transits readably in the communication network N but that it can ultimately be determined by the destination transmission node. This possibility is based on properties of the xor derivation function KDF which states that:

[0049] (A ® kll) ® (kll ® k21) = A ® k21

[0050] The security sought for the transmission of the content A is ensured since, although in possession of the content A ® k21, it is only possible to find the content A with knowledge of the quantum key k21. However, the level of transmission security specific to quantum keys is high insofar as the quantum key distribution network QKDN has the known properties of resistance to a man-in-the-middle attack (MITM attack from the English “Man In The Middle”) since an attempt to reading all or part of a quantum key alters the latter and that an alteration of the quantum key can be detected by its recipient thanks to the phenomenon of quantum entanglement. The content A is then available for an application or an application module waiting for it at the recipient transmission node N3.

[0051] A transmission of the content A can be carried out via a larger number of intermediate transmission nodes. According to another transmission example, the transmission of the content A can be carried out from the transmission node NI (then source transmission node) to the transmission node N5 (then destination transmission node) via the intermediate transmission nodes N2 and N4. According to this other example, successive results of two-input key derivation function KDF operation are sent by the transmission nodes NI, N2 and N4 to the manager KM and quantum keys are addressed in the quantum layer between the transmission nodes NI and N2, then between the transmission nodes N2 and N4 and finally between the transmission nodes N4 and N5. The key management device KM then addresses to the destination transmission node N5 an operation result carried out by itself:

[0052] (A ® kll) ® (kll ® k22) ® (k22 ® k41) = A ® k41,

[0053] where

[0054] kl 1 is the quantum key transmitted between the transmission node NI and the transmission node N2,

[0055] k22 is the quantum key transmitted between the transmitting node N2 and the N4 transmission,

[0056] k41 is the quantum key transmitted between the transmission node N4 and the N5 transmission.

[0057] The content A is transferred here according to the same secure transmission principle as in the previous example relating to a transmission of the content A between the source transmission node NI and the destination transmission node N3.

[0058] The use of a method (or protocol) for managing interactions between the different elements of the communication network advantageously makes it possible to transmit any type of content between two transmission nodes of the communication network N.

[0059] [Fig. 3] illustrates a use of a control plane manager device CP to advantageously organize a sequencing of operations useful for the secure transfer of any content between two transmission nodes of the communication network N. According to one embodiment, the control plane manager device CP is centralized, which means that its resources are concentrated in a dedicated equipment or system, located at a specific place. According to a variant of implementation, the control plane manager device is distributed, which then means that, although it can be considered as a manager device or system dedicated to the organization of the control plane of the communication network N, its resources can be distributed in a plurality of devices remote from each other and configured to cooperate together in the implementation of the management and control functions of the communications network N which are assigned to the control plane manager device CP.

[0060] The control plane manager device CP is configured to be connected to the other devices of the communication network N and can therefore communicate with any transmission node operating in the communication network N, as well as with the key manager device KM, under control of a control unit internal to the control plane manager device CP. According to the example described, the control plane manager device CP is not connected to the quantum key distribution network QKDN of the communication network N, as graphically represented in [Fig. 4], the quantum key distribution network QKDN being used only for the transmission of quantum keys between adjacent nodes. The double arrows shown in [Fig.3] between each of the transmission nodes NI, N2, N3, N4 and N5 of the communication network N and the key management device KM, or between the control plane management device CP and each of the transmission nodes NI, N2, N3, N4 and N5, or between the control plane management device CP and the key management device KM, represent communication links via the so-called IP communication layer and the dotted links of this same [Fig.3] represent links established via optical transmission means capable of carrying out transmissions of quantum keys in the so-called quantum communication layer.

[0061] An example of the internal architecture of the internal control unit of the control plane manager device CP is described further in relation to [Fig.7].

[0062] [Fig. 5] schematically illustrates an example of internal architecture of a transmission node among the transmission nodes NI to N5 of the communication network 1. Let us consider for illustration purposes that [Fig. 5] illustrates an internal arrangement of the transmission node NI. Note that [Fig. 5] could also schematically illustrate an example of hardware architecture of the transmission node N2, N3, N4 or even N5.

[0063] According to the example of hardware architecture represented in [Fig. 5], the transmission node NI then comprises, connected by a communication bus Nl-9: a processor or CPU (“Central Processing Unit” in English) Nl-1; a RAM (“Random Access Memory” in English) N1-2; a ROM (“Read Only Memory” in English) N1-3; a storage unit such as a hard disk (or a storage media reader, such as an SD (“Secure Digital » in English) Nl-4; at least the communication interface Nl-5 allowing the transmission node NI to communicate with devices present in the communication network N such as, for example, the transmission nodes N2, N3, N4 or N5, the key management device KM or the control plane management device CP.

[0064] The processor NI-1 is capable of executing instructions loaded into the RAM Nl-2 from the ROM Nl-3, from an external memory (not shown), from a storage medium (such as an SD card), or from a communication network. When the transmission node NI is powered on, the processor NI-1 is capable of reading instructions from the RAM Nl-2 and executing them. These instructions form a computer program causing the processor NI-1 to implement all or part of a method for transmitting content described in relation to [Fig.l 1] or to [Fig.8] and [Fig.9].

[0065] All or part of a method described in relation to [Fig. 1 1], [Fig. 8] and [Fig. 9], or described variants of this method, may be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (Digital Signal Processor) or a microcontroller, or be implemented in hardware form by a dedicated machine or component, for example an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). In general, the transmission node NI comprises electronic circuitry configured to implement the methods described in relation to itself.Obviously, the NI transmission node also includes all the elements usually present in a system comprising a control unit and its peripherals, such as a power supply circuit, a power supply supervision circuit, one or more clock circuits, a reset circuit, input-output ports, interrupt inputs, bus drivers, this list being non-exhaustive.

[0066] [Fig.6] schematically illustrates an example of the internal architecture of the KM key management device. For illustrative purposes, consider that [Fig.6] illustrates an internal arrangement of the KM key management device.

[0067] According to the example of hardware architecture represented in [Fig. 6], the key management device KM then comprises, connected by a communication bus KM-9: a processor or CPU (“Central Processing Unit” in English) KM-1; a RAM (“Random Access Memory” in English) KM-2; a ROM (“Read Only Memory” in English) KM-3; a storage unit such as a hard disk (or a storage media reader, such as an SD (“Secure Digital” in English) card reader) KM-4; at least the communication interface KM-5 allowing the key management device KM to communicate with devices present in the communication network N, such as, for example, the transmission nodes NI, N2, N3, N4 and N5 or the control plane manager device CP.

[0068] The KM-1 processor is capable of executing instructions loaded into the KM-2 RAM from the KM-3 ROM, from an external memory (not shown), from a storage medium (such as an SD card), or from a communication network. When the KM key manager device is powered on, the KM-1 processor is capable of reading instructions from the KM-2 RAM and executing them. These instructions form a computer program causing the KM-1 processor to implement all or part of a content transmission method described in relation to [Fig. 11] or to [Fig. 8] and [Fig. 9], or described variants of this method.

[0069] All or part of the methods described in relation to [Fig. 11], [Fig. 8] or [Fig. 9], or their described variants may be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (Digital Signal Processor) or a microcontroller, or be implemented in hardware form by a machine or a dedicated component, for example an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). In general, the KM key management device comprises electronic circuitry configured to implement the methods described in relation to itself.Obviously, the KM key management device also includes all the elements usually present in a system comprising a control unit and its peripherals, such as a power supply circuit, a power supply supervision circuit, one or more clock circuits, a reset circuit, input-output ports, interrupt inputs, bus drivers, this list being non-exhaustive.

[0070] [Fig.7] schematically illustrates an example of the internal architecture of the control plane manager device CP.

[0071] According to the example of hardware architecture represented in [Fig. 7], the control plane manager device CP then comprises, connected by a communication bus CP-9: a processor or CPU (Central Processing Unit) CP-1; a random access memory (RAM) CP-2; a read only memory (ROM) CP-3; a storage unit such as a hard disk (or a storage media reader, such as an SD card reader (Secure Digital) CP-4; at least the communication interface CP-5 allowing the control plane manager device CP to communicate (via the IP layer) with devices present in the communication network N, such as for example, the transmission nodes NI, N2, N3, N4 and N5, as well as the key manager device KM.

[0072] The CP-1 processor is capable of executing instructions loaded into RAM CP-2 from ROM CP-3, from an external memory (not shown), from a storage medium (such as an SD card), or from a communication network. When the control plane manager device CP is powered on, the processor CP-1 is able to read instructions from RAM CP-2 and execute them. These instructions form a computer program causing the implementation, by the processor CP-1, of all or part of a method of transmitting content, such as for example content A, through the communication network N, as described in relation to [Fig.l 1] or described variants of this method.

[0073] All or part of the methods described in relation to [Fig. 11], [Fig. 8] or [Fig. 9], or their described variants may be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (Digital Signal Processor) or a microcontroller, or be implemented in hardware form by a machine or a dedicated component, for example an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). In general, the control plane manager device CP comprises electronic circuitry configured to implement the methods described in relation to itself.Obviously, the CP control plane manager device also includes all the elements usually present in a system comprising a control unit and its peripherals, such as a power supply circuit, a power supply supervision circuit, one or more clock circuits, a reset circuit, input-output ports, interrupt inputs, bus drivers, this list being non-exhaustive.

[0074] An example of transmission of a content A between the transmission node NI and the transmission node N3 of the communication network N is illustrated in [Fig. 8]. [Fig. 8] represents a sequencing of operations (or sequences or steps) between the different devices connected to the communication network N and cooperating to carry out the transfer of the content A via the communication network N. According to the example described, the transmission node NI is the source transmission node and the transmission node N3 is the destination transmission node. The content transfer process uses the intermediate node N2 between the source transmission node NI and the destination transmission node N3. The set {NI; N2; N3] constitutes a determined route R for the transmission of the content A via the communication network N.

[0075] Prior to the sequencing illustrated in relation to [Fig.8], a software module at a level higher than the network layer operating the transmission of the content A sends the content A to said network layer in a message 801. In [Fig.8], the successive control messages triggering the successively carried out operations are represented by horizontal arrows between the elements involved, which are the transmission nodes NI, N2 and N3, the key management device KM and the control plane manager device CP. Each of the transmission nodes is illustrated by a double vertical bar (IP layer denoted "IP" and quantum layer denoted "Q"). A reading from top to bottom corresponds to the passage of time, symbolized by the vertical arrow annotated t in [Fig.8]. It is considered here that sending a message is of negligible duration and that an arrow representing it is consequently horizontal. According to one embodiment, the content A is transmitted in its entirety to the transmission node NI. According to a variant, the content A is fragmented into a plurality of fragments and the process described below is repeated as many times as necessary to transmit the entire content A by successive transmissions of the fragments of the content A. The message 801 includes information according to which the content A is intended to be transmitted to the transmission node N3 of the communication network N.The network layer of the transmission node NI configured to collaborate in the transmission of the content A then sends to the control plane manager device CP, during a step SI, a message 802 requesting transmission of the content A. This message 802 requesting transmission of the content A includes information according to which the transmission node receiving the content A is the transmission node N3. During a step S2 (not being associated with sending a control message), the control plane manager device CP determines a route (here, the route R = {NI; N2; N3}) in the communication network. The determination of the route R is for example such as to optimize the transmission time of the content A in the communication network N, or determined according to the reliability of the transmission links between the different transmission nodes of the communication network N, or according to a combination of the two.According to another example, the determination of a route depends on the quantum keys available in the quantum key buffer memories of all or part of the quantum interfaces of the transmission nodes. These examples are obviously not limiting and the determination of a route R between the source transmission node and the destination transmission node can be arbitrary. The implementation details of a method for determining a route R between a source transmission node and a destination transmission node via one or more successive intermediate nodes are not developed here to the extent that this is not useful for a good understanding of the invention. A person skilled in the art will know how to choose an algorithm for determining a route from multiple routing possibilities according to the typology of the communication network N and any other parameters or constraints.According to one embodiment, the control plane manager device CP obtains a route determined by and from a third-party device configured to perform such route determination based on one or more predefined parameters.

[0076] Once the route R is obtained, the control plane manager device CP having received the request for transmission of the content A assigns a service identifier (a number, for example) Servld to the content transmission, making it possible to create a common reference to any operation required in connection with this transmission of the content A between the source transmission node and the destination transmission node. This assignment is also carried out during step S2. The control plane manager device CP then sends, during a step S31, a control message 803 to the key manager device KM. This message 803 includes the assigned service identifier Servld, which allows the control plane manager device CP to carry out actions in relation to the transfer of the content A in the communication network N, depending on other future control messages. The control plane manager device CP then determines and operates a precise sequencing to organize the transfer of the content A via the determined route.Thus, a first control message is sent to the source transmission node, then control messages are successively sent to all the intermediate nodes of the route, and finally a control message is sent to the destination transmission node. This control message sent to the destination node is preceded by a control message sent to the key management device KM, which can then indicate to the destination transmission node that it is the last transmission node of the route determined in relation to the transmission service identified via the service identifier Servld; the indication allowing the destination node to carry out actions of its own.

[0077] Thus, a control message 804 is sent by the control plane manager device CP to the transmission node NI during a step S32a, which control message 804 comprises the service identifier Servld as well as an identifier of a quantum key transmission interface of the transmission node NI, or more precisely of a quantum interface of the quantum module QN1 of the transmission node NI. The choice of the quantum key transmission interface is determined so that the quantum module QN1 can send a quantum key to the next transmission node in the path that is the route R determined for the transmission of the content A in the communication network N.To do this, each of the transmission nodes NI, N2 and N3, has previously notified the control plane manager device CP of the number of quantum key transmission interfaces it has and to which adjacent transmission node device each of its interfaces is connected. These notifications are made in a preliminary phase of recognition of the characteristics of the interconnected transmission nodes to form the communication network N.

[0078] The control message 804 therefore allows the transmission node NI to know to which next transmission node in the determined route R it must send a key. quantum enabling this same node to carry out subsequent operations participating in the secure transmission of the content A, in particular by operating a key derivation function and by addressing the result of this operation to the key management device KM. To follow up on the reception of the control message 804, the transmission node NI transmits in a message 804' a quantum key kll to the transmission node N2, defined as being the next transmission node in the determined route. The transmission node NI then sends a control message 805, during a step S32b, in response to the control message 804 that it has received.

[0079] The control message 805 sent by the transmission node NI to the control plane manager device CP comprises the service identifier Servld used as a common reference for any control message related to the transmission of the content A in the communication network N, as well as an identifier of the quantum key transmitted to the transmission node N2 (the next node in the determined route) to be considered for carrying out the subsequent operations for which this transmission node is responsible. In addition, the transmission node NI, the source node, operates a key derivation function KDF, here of the xor type between the content A and the quantum key sent to the transmission node N2, and addresses the result thereof to the key manager device KM in a control message 806 further comprising the service identifier Servld.According to a substantially similar process, except that the next node in the determined route R is not the source node, but in fact an intermediate node, the control plane manager device CP then sends to the intermediate transmission node N2, during a step S33a, a control message 807, which control message 807 comprises the service identifier Servld and a quantum key transmission interface identifier to be used to send, from the transmission node N2, a quantum key to the next transmission node in the determined route R, in this case and according to the example described, the destination transmission node N3.In a similar manner to what was implemented by the source transmission node NI, the intermediate transmission node N2 sends a quantum key k21 to the transmission node N3 (the next in the determined route) in a message 807', as well as a control message 808, during a step S33b, in response to the control message 807 received, and a control message 809 to the key manager KM. The control message 809 sent to the key manager KM comprises the result of a key derivation function KDF applied to the quantum key received from the previous node and to the quantum key sent to the next node, together with the service identifier Servld. For its part, the key manager KM operates a key derivation function KDF, here in this case the xor function, between the result previously received from the transmission node NI (source node) and the result received from the transmission node N2 (intermediate node) and retains this result. THE . The control plane manager device CP then sends a control message 810, during a step S34, to the key manager device KM, considering that the next transmission node in the determined route R is the destination node N3. The control message 810 comprises, in addition to the service identifier Servld, information according to which the next transmission node, in this case the transmission node N3, is the destination transmission node of the content A, or in other words, the last node of the determined route R. This information constitutes an end of sequence identifier. According to an exemplary implementation, the end of sequence identifier is a specific code such as, for example, the code “FF”.According to one embodiment, this code is transmitted in a data field intended to carry a sequence number such as a unique sequence identifier of a series of unique sequence identifiers determined for the transmission of the content A in relation to the service identifier Servld. This control message allows the key management device KM to know that it must send to the destination transmission node a control message comprising the final result of the successive key derivation function KDF operations that it has carried out. This final result is here, and according to the transmission example already described in relation to [Fig.2]: (A ® kl 1) ® (kl 1 ® k21). The control plane management device CP further sends, during a step S35, a control message 811 to the destination transmission node N3.This control message 811 comprises, in addition to the service identifier Servld, a quantum key identifier to be considered for carrying out a subsequent operation of determining the content A from the quantum key received from the previous intermediate transmission node in the determined route and the final result of key derivation operations received from the key management device KM. The final result of the operations carried out by the key management device KM is sent to the destination transmission node N3 in a control message 812. Finally, the destination node device N3 sends the content A in a message 813 to an application layer or at least to an application module of the transmission node N3 configured to receive the content A or the fragment of the content A concerned in the case where the content A is transmitted in a fragmented manner by a succession of executions of the sequencing described above.

[0080] Overall and to summarize, the sequencing of operations aimed at transmitting the content A, or where appropriate a fragment of content A, between a source transmission node and a destination transmission node, possibly via a plurality of intermediate transmission nodes, according to a determined route R, comprises the sending and receiving of control messages, by the control plane manager device CP, successively, to each of the transmission nodes constituting the determined route R (of transmission), here considered as the “transmission node current”, so that: - the current transmitting node sends, via one of its quantum key transmission interfaces, a quantum key to the next node in the determined route, unless the current node is the destination transmitting node, - the current transmission node sends to the key management device KM a result of a key derivation function KDF applied to a received quantum key, on the one hand, and a sent quantum key, on the other hand, when the current transmission node is an intermediate transmission node, or a result of this key derivation function KDF applied to the content A or to a fragment of the content A on the one hand, and a sent quantum key, on the other hand, when the current transmission node is the source transmission node, - the current transmission node receives from the key management device KM a final result of successive key derivation operations and determines the content A or a fragment of the content A, if applicable, when the current transmission node is the destination node.

[0081] For this, the control plane manager device CP also sends, prior to these control messages, a first control message (or prior message) to the key manager device KM, when the current transmission node is the source node, and a second control message (or end of sequence message) to the key manager device KM, when the current transmission node is the destination transmission node. The first message sent to the key manager device KM comprises a transmission service identifier Servld and the second message sent to the key manager device KM comprises information according to which the current transmission node is the destination transmission node of the content A or of a fragment of the content A, where appropriate.

[0082] It is clear from the above summary that the method for transmitting a content A as described is also functional between a source transmission node and a destination transmission node when these two transmission nodes are adjacent in the communication network N, that is to say in the absence of an intermediate transmission node between the source transmission node and the destination transmission node. Indeed, nothing excludes content from being addressed between two adjacent transmission nodes.

[0083] In such a case, the source transmission node (for example NI) operates a key derivation function KDF between the content A to be transmitted (or a fragment of this content where appropriate) and a quantum key which it has (kl 1, for example) and in then transmits the result rel to the key management device KM, in addition to transmitting this quantum key kl 1 to the next transmission node, which is the destination node (for example N2). For its part, the destination node (here N2) therefore receives, from the key management device KM, the result rel of the KDF derivation function previously operated by the source node, and operates a new KDF key derivation function between this received result rel and the received quantum key kl 1, so as to find the content A transmitted. Thus, and even in the absence of an intermediate transmission node in the determined (direct) route, the transmission of the content is secure since ((A® kll)®kll) = A with rel = (A® kl 1) which passes via the key management device KM.

[0084] According to the exemplary embodiment described here, the key derivation function KDF is the xor function. This example is however not limiting and another key derivation function KDF having the same properties according to which when said KDF function is applied to two data a and b, called input data, the result re = KDF (a, b) of said function applied to said two data is zero when said two data a and b are equal to each other, and that the result re = KDF (a, b) of said KDF function (a, b) applied to said two data a and b is equal to one of said two data among a and b when the other of said two data among a and b is zero.

[0085] According to one embodiment, an acknowledgment of receipt is delivered to the sender of a control message by the recipient of the control message for each of the described control messages. This concerns the control messages sent from the transmission nodes, the key management device KM and the control plane management device CP. This advantageously makes it possible in particular to detect a malfunction or an interruption of a transmission link in the communication network N.

[0086] A communication network is subject to drops in communication performance due to congestion or malfunctions; monitoring of the network performance may lead to the determination of a new route R for the transmission of content, either prior to the start of transmission or during transmission.

[0087] [Fig. 9] describes a sequencing of operations suitable for a transmission of the content A in the communication network N when the communication link of the quantum layer of the communication network N already described is interrupted between the transmission node N2 and the transmission node N3, still in the case of a transmission between the source transmission node NI and the destination transmission node N3. According to the example described in relation to [Fig. 9], the route R' determined by the control plane manager device CP is then R' = {NI; N2; N4; N5; N3}. After receiving the content A in a message 901, at the level of the transmission node N2 and the destination transmission node N3, the route R' determined by the control plane manager device CP is then R' = {NI; N2; N4; N5; N3}. transmission NI, the source transmission node NI sends to the control plane manager device CP a message 902 comprising a request for transmission of the content A to the transmission node N3. The control plane manager device CP determines the route R' = {NI; N2; N4; N5; N3} making it possible to avoid a quantum key transmission between the transmission node N2 and the transmission node N3, the useful link for this being faulty, as well as a service identifier Servld specific to this transmission via this determined route R'. The control plane manager device CP then sends this service identifier Servld to the key manager device KM in a control message 903. Then, just as in the example previously described in relation to [Fig. 8], for each of the successive source and intermediate transmission nodes NI, N2, N4 and N5 defining the determined route R' {NI; N2; N4; N5; N3} to the destination transmission node N3, the control plane manager device CP sends a control message determining on which quantum key transmission interface the current transmission node must address a quantum key, and receives a message comprising a quantum key identifier to be processed by the next transmission node in the determined route. Sending the control message to the current transmission node further triggers the sending, by the transmission node configured to do so, of a message comprising the result of a key derivation operation, via a key derivation function KDF, to the key management device KM.Thus, the control plane manager device CP successively sends a control message 904 to the source transmission node NI which responds to it with a control message 905, a control message 907 to the intermediate transmission node N2 which responds to it with a control message 908, a control message 910 to the intermediate transmission node N4 which responds to it with a control message 911, a control message 913 to the intermediate transmission node N5 which responds to it with a control message 914. These control messages respectively trigger the transmission of quantum keys in messages 905', 908', 911' and 914'.Finally, the control plane manager device CP sends a control message 916 to the key manager device KM comprising information according to which the next transmission node is the destination node, so that the key manager device KM transmits, in a message 917, the final result of successive operations of key derivation functions that it has carried out from the messages 906, 909, 912 and 915 received from each of the source and intermediate nodes defining the route R' determined towards the destination node N3 and each comprising a result of a key derivation operation carried out by the transmission node sending the message in question. The control plane manager device CP then sends a control message 918 to the transmission node. recipient N3, which message includes a quantum key identifier to be considered to retrieve the content A from the final result received from the key management device KM and the quantum key received from the previous transmission node in the determined route R'. The recipient transmission node N3 then transmits, in a message 919, the reconstituted content A to an application module of the recipient transmission node N3 intended to receive it. In the same way as for the transmission example already described in relation to [Fig.8], the content A can be transmitted in full according to the method described above, or even broken down into fragments so that the fragments are successively transmitted during successive iterations of the method described above.

[0088] According to one embodiment, the control messages sent by the control plane manager device CP to the source transmission node or to the intermediate transmission nodes each comprise a unique sequence identifier SeqNum of a sequence of unique sequence identifiers determined for the transmission of the content A in relation to the service identifier Servld. According to this embodiment, each unique sequence identifier of the sequence of unique sequence identifiers is capable of determining the rank of a sequence (or of an operation, or step) with which it is associated in a sequence of sequences defined in relation to the transmission of the content A.This advantageously makes it possible to define an order for carrying out successive operations carried out by the KM key management device in the case where the key derivation function used by the KM key manager does not have commutativity properties allowing successive operations to be carried out whose result is independent of the sequencing, as is the case for the xor function, for example, applied to two input data a and b. In addition, the use of a unique sequence identifier makes it possible to operate by modifying the route determined during transmission of a content A in the event of a malfunction of a transmission node, by resuming routing from a previous node in the route determined by the control plane management device.

[0089] Still according to this embodiment, each of the transmission nodes is configured to relay to the key management device KM, in the message comprising a key derivation function result, the unique sequence identifier that it received from the control plane manager CP. According to a variant, the transmission nodes are not configured to relay to the key management device KM the unique sequence identifiers received from the control plane manager device CP, and the latter directly sends these unique identifiers, defined in a coherent manner (for example by following an incremental order), so that the key management device KM knows how to schedule the operations to be carried out according to the respective values ​​of these unique identifiers received from the CP control plane manager device.

[0090] [Fig. 11] is a flowchart illustrating the steps of a method for transmitting a content A through the communication network N, between the transmission node NI, called the source node, and the transmission node N3, called the destination node. A step S0 corresponds to an initialization step at the end of which all the transmission nodes NI, N2 and N3 are configured to operate nominally, communications via so-called IP communication links, and transmissions of quantum keys via the quantum key distribution network QKDN. At the end of step S0, the key management device KM and the control plane management device CP are also configured and ready to operate. In particular, each of the transmission nodes is ready to receive from an application layer or an application module, a message comprising a request for transmission of a content in the communication network N.During step S1, the source node N1 receives a message comprising a request for transmission of the content A to the destination node N3, also called a transmission request message. The source node N1, having then interpreted that it must operate as a source node, sends a message requesting transmission of the content A to the control plane manager device CP, configured to orchestrate content transmissions in the communication network N. The control plane manager device CP then determines, during step S2, a route R for transmission of the content A in the communication network N. According to the example described here, the determined route R comprises the transmission node N2 called the intermediate node N2.The control plane manager device further determines a service identifier Servld, associated with the determined route R, which identifier can serve as a reference for any subsequent action useful for the transmission of a content A through the communication network N, and in particular to refer to this transmission of the content A in control messages that it defines to orchestrate the interactions between the transmission nodes NI, N2, N3, the key manager device KM and itself. Finally, during step S3, the control plane manager device CP determines and sends successive control messages to operate the transmission of the content A using the quantum key distribution network QKDN in order to best secure the transmission of the content A. According to the example described here, the control messages for the transfer of the content A in step S3 are the messages 803 to 813 as described in relation to [Fig.8] or equivalent messages or messages (potentially including additional information).

[0091] According to one embodiment of the invention, the control messages exchanged during step S3 comprise additional information, in addition to that useful for the transmission of the content A according to the method described. For example, such information can be used to avoid the use of two identical quantum keys.

[0092] According to one embodiment, a quantum key identifier may be a quantum key length and each of the quantum keys generated in the same transmission node has a different length, at least in the same reference period.

[0093] The method for transmitting content, executed by the control plane manager device CP, advantageously makes it possible to carry out end-to-end control of the operations necessary for secure transmission of the content A by offering a very high level of security with regard to the use of a quantum key distribution network. It is thus possible to avoid numerous attacks, in particular attacks of the “man-in-the-middle” type. Advantageously, such a method also makes it possible to make modifications to the routing during transmission. The method is also compatible with quantum keys of any size.

[0094] For reasons of performance and infrastructure cost, the quantum distribution network QKDN used for the distribution of quantum keys between the transmission nodes that compose it is dedicated to this use. Thus, only quantum keys transit in the quantum network QKDN. The control messages transit between the transmission nodes and the control plane manager device CP, between the transmission nodes and the key manager device KM, or between the latter and the control plane manager device CP. In particular, the quantum key identifiers used according to the content transmission protocol in the communication network N generally transit via so-called "classic" IP communication links, which are inherently less secure than the optical quantum links used for quantum key transmissions.

[0095] According to one embodiment, and for the purpose of further securing the transmission of content in the communication network N, the quantum key identifiers transmitted in control messages are each transmitted in the form of a digest of the quantum key transmitted or to be transmitted that they identify. Thus, for example, an identifier KIDnj making it possible to refer to a quantum key Knj, transmitted or to be transmitted from a quantum interface Qj of a transmission node Nn, is the digest KIDnj = H (Knj) where H is the hash function used.

[0096] A quantum key digest (or "hash", or even "hashcode") is determined (calculated) so as to be unique for each quantum key possibly used. For this, a quantum key constructed by a quantum key generator is used only once. The term "digest" here designates the result of a cryptographic hash function H applied to a quantum key transmitted or to be transmitted, making it possible to identify this quantum key for subsequent processing during which This quantum key is referred to.

[0097] [Fig. 12] illustrates a transmission of a first digest KID14 of a quantum key K14 transmitted between the transmission nodes NI and N2 of the communication network N according to a step of the content transmission protocol described in the present application. The digest is used here as an identifier of the quantum key K14 for one or more subsequent processing operations. The digest KID14 is calculated by the transmission node NI, by applying the hash function H to the quantum key K14. According to one embodiment, the hash function H is the SHA-256 function of the well-known SHA-2 family of hashing algorithms, or the SHA-512 function. This example is not limiting and another hash function may be used, such as, for example, MD4 or MD5. The quantum key K14 is transmitted by the transmission node NI, from its quantum interface Q4, to the transmission node N2.The digest KID14 calculated by the transmission node NI acts as an identifier of the quantum key K14 in a first control message sent from the transmission node NI to the control plane manager device CP, then in a second subsequent control message sent from the control plane manager CP to the node N2 which is the next node in the route determined to transmit content between a source transmission node and a destination transmission node. Upon receipt of the quantum key K14, the transmission node N2 performs a digest calculation by applying the same hash function H as that previously used by the transmission node NI and then obtains a second digest KID' 14 which, unless there is a calculation error linked to a malfunction, is equal to the first digest KID 14 calculated by the transmission node NI.The transmission node N2, which has received the quantum key K14, then records this quantum key K14 in association with the second digest KID' 14, in a memory M2, which is preferably internal to it. The memory M2 contains a list of quantum keys ordered so that each of the quantum keys stored therein is associated with a quantum key identifier which is a digest of the quantum key. The term "list" is used here broadly and also includes the case of a single-rank list (a single quantum key and its identifier in the form of a digest of this quantum key).

[0098] Advantageously, the use of a condensate, resulting from a hash function H, increases the security of the overall transmission and reduces the attack surface of such a transmission in the communication network N.

[0099] Cleverly, and to do this, each of the transmission nodes present in the communication network N and comprising at least one quantum interface (for example the transmission nodes NI and N2) comprises, in addition to means for generating, storing and transmitting a quantum key, electronic circuitry electronics and / or IT configured for: - operate a hash function H having as input variable (data) a quantum key Knj transmitted or to be transmitted to an adjacent transmission node, - transmit a first digest KIDnj, result of this hash function H applied to said quantum key Knj transmitted or to be transmitted, via a preferably non-quantum transmission link and towards the control plane manager device CP, in a control message established according to the content transmission method in the communication network N,

[0100] and for: - operate the hash function H having as input variable (data) a quantum key Knj received from an adjacent transmission node to obtain a second digest KID'nj (identical to the first digest KIDnj, except for malfunction) and record in a memory, preferably internal, the second digest KID'nj in association with said quantum key Knj received, - receive, from said control plane manager CP, via a preferably non-quantum communication link, the first digest KIDnj operating as an identifier of a quantum key Knj, and, - identify the quantum key Knj received, with a view to carrying out subsequent processing, by comparing the first condensate KIDnj received with a list of condensates including the second condensate KID'nj determined.

[0101] By being configured in this way, each transmission node thus provided can address a quantum key Knj to another transmission node of the network and address a highly secure identifier KIDnj of this quantum key Knj to the control plane manager device CP, which can then address this identifier to the next node in the determined route to carry out a content transfer in the communication network N. The next node will be able to find the quantum key Knj concerned, by browsing its memory in which the determined condensates of quantum keys received are stored, to operate, if necessary, a key derivation function, and address the result to the key manager device KM as well as any subsequent operation useful for implementing a content transfer according to the method described.According to one embodiment, the method for transmitting a quantum key identifier in the form of a digest comprises a concatenation of the quantum key with a salt, to further increase the level of security. According to this embodiment, the salt is known to all the transmission nodes, by parameterization. In this case, the salt used for hashing the quantum key can be fixed or vary over time. For example, a new salt common to all the transmission nodes can be . addressed regularly to the transmission nodes of the communication network N, or the latter may each include a table of salts.

Claims

Claims

1. Method for transmitting content (A) between two transmission nodes (NI, N3) of a communication network (N) comprising said two transmission nodes (NI, N3) and at least one other transmission node (N2) called intermediate transmission node (N2), said transmission nodes (NI, N2, N3) being further included in a quantum distribution network (QKDN) of keys called quantum keys (Knj), the communication network comprising a key management device (KM) connected to said transmission nodes (NI, N2, N3) and connected to said quantum distribution network (QKDN) of keys, said transmission nodes (NI, N2, N3) each comprising a plurality of communication interfaces (IPI,...,IPi) for communicating in the communication network and a plurality of interfaces for transmitting quantum keys (Ql, ..., Qj) for transmitting and receiving said quantum keys (Knj) in said quantum key distribution network, and said transmission nodes being further configured to each operate a key derivation function (KDF) and send the result thereof to said key management device (KM) and to each operate a key extraction function from information received from said key management device (KM) and from a quantum key, said communication network further comprising a control plane manager device (CP) connected to said transmission nodes (NI, N2, N3) and to said key management device (KM) and whose resources are concentrated in equipment or a system dedicated to the organization of a sequencing of operations useful for the secure transfer of content between two transmission nodes of the communication network (N) configured to execute the steps:. - receiving (SI), from one (NI), called source node, among said two transmission nodes (NI, N3), a request message for transmission of said content (A) to the other (N3), called destination node, among said two transmission nodes (NI, N3), said request message comprising an identifier of said destination node (N3), - obtaining (S2) a route (R) determined as passing through said at least one intermediate transmission node (N2) or through a series of intermediate transmission nodes between said source node (NI) and said destination node (N3), and a

2. service identifier (Servld) for transmission of said content (A) associated with said route, - transmitting and receiving control messages (S3) to and from said transmission nodes (NI, N2, N3) and to said key management device (KM), capable of generating key transmissions (Knj) between pairs of nodes among said nodes (NI, N2, N3), defined according to said route (R) determined in relation to said transmission service identifier (Servld), said transmission method being characterized in that, when a control message sent to or from said control plane manager (CP) comprises an identifier of a quantum key (Knj) transmitted or to be transmitted between two transmission nodes (NI, N2, N3), this identifier is a condensate of said quantum key (Knj) transmitted or to be transmitted. Method for transmitting content (A) according to claim 1, wherein sending and receiving said control messages (S3) comprise: - sending (S31), to said key management device (KM), a control message comprising said service identifier (Servld), - send, to said source node (NI), a control message comprising at least said service identifier (Servld) and an identifier of a quantum key transmission interface, - receive, from said source node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said service identifier (Servld) for transmitting said content (A), - sending, to each intermediate transmission node, a control message comprising at least said service identifier (Servld), a quantum key reception interface identifier, a quantum key identifier received or to be received, in the form of a digest of said quantum key via said quantum key reception interface and a quantum key transmission interface identifier, - receive, from each intermediate transmission node, a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said service identifier (Servld) for transmitting said content (A), - sending, to said key management device (KM), a control message comprising an end of sequence identifier and an identifier of the destination node, and, - sending, to said destination node, a control message comprising at least said service identifier (Servld), a quantum key reception interface identifier and a quantum key identifier in the form of a digest of said quantum key received or to be received via said quantum key reception interface.

3. A method of transmitting content (A) according to claim 2, wherein sending the control message to said source node (NI) and sending a control message to each of said intermediate nodes (N2) further comprises a unique sequence identifier of a sequence of unique sequence identifiers determined for said transmission of said content (A) in relation to said service identifier (Servld), each unique sequence identifier of said sequence of unique sequence identifiers being capable of determining the rank of a sequence with which it is associated in a sequence of sequences defined in relation to said transmission of said content (A).

4. Method for transmitting a content (A) according to one of claims 1 to 3, in which the key derivation function (KDF) has properties according to which said function (KDF) applies to two data (a, b), called input data, and that the result (re) of said function applied to said two data is zero when said two data (a, b) are equal to each other and that the result (re) of said function (KDF) applied to said two data is equal to one of said two data when the other of said two data is zero.

5. Method for transmitting content (A) according to the preceding claim, in which the key derivation function (KDF) is a so-called "exclusive OR" function and in which said two data (a, b) have the form of binary words (a, b) of identical sizes (w).

6. Communication network (N) comprising a management devicecontrol plane (CP) configured to operate a transmission control of a content (A) between two transmission nodes (NI, N3) of said communication network (N) further comprising at least one other transmission node (N2) called intermediate transmission node (N2), said transmission nodes (NI, N2, N3) being further included in a quantum distribution network (QKDN) of keys called quantum keys (Knj), the communication network (N) comprising a key management device (KM) connected to said transmission nodes (NI, N2, N3) and connected to said quantum distribution network (QKDN) of keys, said transmission nodes (NI, N2, N3) each comprising a plurality of communication interfaces (IPI,...,IPi) for communicating in the communication network and a plurality of quantum key transmission interfaces (Ql,...,Qj) for transmitting and receiving said quantum keys (Knj) in said quantum distribution network (QKDN) of keys,and said transmission nodes (NI, N2, N3) being further configured to each operate a key derivation function (KDF) and send the result thereof to said key management device (KM) and to each operate a key extraction function (KDF) from information received from said key management device (KM) and from a quantum key, said communication network further comprising said control plane manager device (CP) connected to said transmission nodes (NI, N2, N3) and to said key management device (KM) and, said control plane manager device (CP) comprising electrical and electronic circuitry whose resources are concentrated in equipment or a system dedicated to the organization of a sequencing of operations useful for the secure transfer of content between two transmission nodes of the communication network and configured to:, - receiving (SI), from one (NI), called source node, among said two transmission nodes (NI, N3), a request message for transmission of said content (A) to the other (N3), called destination node, among said two transmission nodes (NI, N3), said request message comprising an identifier of said destination node (N3), - obtaining (S2) a route (R) determined as passing through said at least one intermediate transmission node (N2) or through a series of intermediate transmission nodes between said

7. source node (NI) and said destination node (N3), and a service identifier (Servld) for transmitting said content (A) associated with said route, - transmitting and receiving (S3) control messages to and from said transmission nodes (NI, N2, N3) or to said key management device (KM), capable of generating key transmissions (Knj) between pairs of nodes among said nodes (NI, N2, N3), defined according to said route (R) determined in relation to said transmission service identifier (Servld), said communication network being characterized in that, when a control message sent to or from said control plane manager (CP) comprises an identifier of a quantum key (Knj) transmitted or to be transmitted between two transmission nodes (NI, N2, N3), this identifier is a condensate of said quantum key (Knj) transmitted or to be transmitted. Communication network (N) according to claim 6, wherein the control plane manager device (CP) further comprises electronic circuitry configured to: - send, to said key management device (KM), a control message comprising said service identifier (Servld), - send, to said source node (NI), a control message comprising at least said service identifier (Servld), an identifier of a quantum key transmission interface, - receive, from said source node (NI), a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said service identifier (Servld) for transmitting said content (A), - sending, to each intermediate transmission node (N2), a control message comprising at least said service identifier (Servld), a quantum key reception interface identifier and a quantum key identifier received or to be received in the form of a digest of said quantum key via said key reception interface quantum keys, a quantum key transmission interface identifier, - receive, from each intermediate transmission node (N2), a control message comprising at least one quantum key identifier in the form of a digest of said quantum key and said service identifier (Servld) for transmitting said content (A), - send, to said key management device (KM), a control message comprising an end of sequence identifier and an identifier of the destination node, and, - send, to said destination node (N3), a control message comprising at least said service identifier (Servld), a quantum key reception interface identifier and a quantum key identifier received or to be received in the form of a digest of said quantum key via said quantum key reception interface.

8. Communication network (N) according to claim 7, wherein the control plane manager device, comprising electronic circuitry configured to insert into the control message to said source node (NI) and into the control message to each of said intermediate nodes (N2) a unique sequence identifier (SeqNum) of a sequence of unique sequence identifiers determined for said transmission of said content (A) in relation to said service identifier (Servld), each unique sequence identifier (SeqNum) of said sequence of unique sequence identifiers being capable of determining the rank of a sequence with which it is associated in a sequence of sequences defined in relation to said transmission of said content (A).

9. Communication network (N) according to one of claims 6 to 8 comprising a plurality of transmission nodes (NI, N2, N3, N4, N5), wherein each of the transmission nodes is further configured to: - send a control message to the key management device (KM), said message addressed to said key management device (KM) comprising a key derivation function result, said service identifier (Servld) and a sequence identifier of a sequence of unique sequence identifiers determined for said transmission of said content (A) in relation to said service identifier (Servld), each unique sequence identifier of said sequence of unique sequence identifiers being capable of determining the rank of a sequence

10. to which it is associated in a sequence of sequences defined in relation to said transmission of said content (A), and - receiving from said key management device (KM) a control message comprising said service identifier (Servld) and a key derivation function result. Transmission node (NI, N2, N3, N4, N5) in a quantum distribution network (QKDN) of quantum keys (Knj), the transmission node being configured to operate, from at least one quantum key (Kjn), a key derivation function or a key extraction function, said transmission node comprising means for generating, storing, receiving and transmitting a quantum key (Knj), said transmission node (NI, N2, N3, N4, N5) further comprising means for receiving and transmitting control messages capable of operating, in combination with a key management device (KM) and a control plane management device (CP), a method for transmitting a content (A) in a communication network (N) comprising said transmission node (NI, N2, N3, N4, N5), and said transmission node being characterized in that it comprises electronic and / or computer circuitry configured for,when a quantum key sending from said transmission node is required:, - operate a hash function (H) having as input variable said quantum key (Knj) transmitted or to be transmitted, - transmitting a first digest (KIDnj), result of said hash function (H) applied to said quantum key (Knj) transmitted or to be transmitted, said first digest operating as an identifier of said quantum key (Kjn) according to said content transmission method, and for, from a quantum key (Knj) received by said transmission node: - operate said hash function (H) having as input variable said quantum key (Knj) received to obtain a second condensate (KID'nj) and record in a memory (M2), the second condensate (KID'nj) in association with said quantum key (Knj) received, - receiving the first digest (KIDnj) operating as a quantum key identifier, and, - identifying a quantum key (Knj) received, by comparing the first digest (KIDnj) with a list of digests comprising the second digest (KID'nj) determined.

11. Computer program product comprising program code instructions for executing the steps of the method according to one of claims 1 to 5, when said program is executed by a processor of a control plane (CP) manager device.

12. Storage medium comprising a computer program product according to the preceding claim.

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