WO2021192059A1

WO2021192059A1 - Terminal and communication method

Info

Publication number: WO2021192059A1
Application number: PCT/JP2020/013116
Authority: WO
Inventors: 高橋　秀明; アルフツーゲンマイヤー
Original assignee: 株式会社Ｎｔｔドコモ
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2021-09-30

Abstract

Provided is a terminal comprising: a control unit which applies a keystream calculated by a specific algorithm to one or a plurality of packets, with at least a bearer identifier, a count value corresponding to a data unit, and a specific encryption key as input parameters, and which encrypts said one or plurality of packets; and a transmission unit which uses the bearer to transmit the encrypted one or plurality of packets to a base station, wherein if it is detected that a specific count value assigned to the data unit that is transmitted first out of the one or plurality of data units is applied to a data unit other than the data unit that is transmitted first out of the one or plurality of data units, then the control unit starts up a reconnection procedure pertaining to a connection with the base station.

Description

Terminal and communication method

The present invention relates to a terminal and a communication method in a wireless communication system.

In the case of NR (New Radio), as in the case of LTE (Long Term Evolution), a stream encryption method that encrypts data and key stream by exclusive OR (XOR) is adopted for data encryption. Has been done. In this method, it is important that the key stream is not reused. NEA (New Radio Encryption Algorithms), which is an NR encryption algorithm, only generates a key stream of a finite length. Therefore, in order to avoid reuse of the key stream, it is conceivable to change the key used for generating the key stream at an arbitrary timing, for example, at the time of handover.

"Key change on-the-fly" includes updating the key to the latest key (key refresh) or regenerating the key (re-keying). It is possible to apply "key refresh", which is a procedure for updating a key to the latest key, to KgNB, KRRC-enc, KRRC-int, KUP-enc, and KUP-int. Here, when a specific PDCP COUNT value is used again for the same bearer identifier and the same KgNB, "key refresh" is started by gNB / ng-eNB.

To prevent the same COUNT value (ie, the same key stream) from being used twice for the transmission of data in the same bearer, the base station will use the same COUNT value again when it is about to be used. Perform "key refresh". However, if the same COUNT value is about to be used again and the base station does not perform "key refresh", the terminal may use the same COUNT value again.

There is a need for a method to reduce the possibility that the same COUNT value will be reused for the transmission of encrypted data with the same bearer.

According to one aspect of the present invention, a bearer for transmitting one or more data units is set in the base station, and each data unit of the one or more data units is divided into one or a plurality of packets. , In the case of sequentially transmitting the divided one or a plurality of packets, a count value for sequentially counting the number of transmitted data units is maintained, and each data unit of the one or a plurality of data units is supported. When transmitting one or more packets, a specific algorithm with at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters for the one or more packets. A control unit that encrypts the one or more packets by applying the key stream calculated by the above, and a transmission unit that transmits the encrypted one or more packets to the base station by the bearer. , The control unit is the first of the one or more data units to have a specific count value assigned to the first transmitted data unit of the one or more data units. A terminal is provided that, when detected to apply to a data unit other than the transmitted data unit, initiates a reconnection procedure for a connection with the base station.

According to the embodiment, a method for reducing the possibility that the same COUNT value is reused for the transmission of encrypted data in the same bearer is provided.

It is a figure which shows the example of the structure of the communication system in this embodiment. It is a figure which shows the example of the layering of the key used in NR. It is a figure which shows the operation example of the encryption algorithm (ciphering algorithm). It is a figure which shows the operation example of the integrity algorithm. It is a figure which shows the example of the procedure which the terminal autonomously prevents the reuse of the same COUNT value. It is a figure which shows an example of the functional structure of a terminal. It is a figure which shows an example of the functional structure of a base station. It is a figure which shows an example of the hardware composition of a terminal and a base station.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments.

The wireless communication system in the following embodiments is basically assumed to be LTE compliant, which is an example, and the wireless communication system in the present embodiment is a part or all of the radios other than LTE. It may be compliant with a communication system (eg LTE-A, NR).

(Overall system configuration)
FIG. 1 is a diagram showing an example of a configuration of a wireless communication system according to the present embodiment. As shown in FIG. 1, the wireless communication system according to the present embodiment includes a terminal 10 and a base station 20 (which may be a base station simulator). Although FIG. 1 shows one terminal 10 and one base station 20, this is an example, and there may be a plurality of each. When a base station simulator is used instead of the base station 20, instead of forming a cell as shown in FIG. 1, a fading simulator and an attenuator are used between the base station simulator and the terminal 10. The test environment may be configured by connecting the base station simulator and the terminal 10 with a coaxial cable or the like after interposing such as.

The terminal 10 is a communication device having a wireless communication function such as a smartphone, a mobile phone, a tablet, a wearable terminal, and a communication module for M2M (Machine-to-Machine), and is wirelessly connected to the base station 20 by a wireless communication system. Use the various communication services provided. The base station 20 is a communication device that provides one or more cells and wirelessly communicates with the terminal 10.

In the present embodiment, the duplex system may be a TDD (Time Division Duplex) system or an FDD (Frequency Division Duplex) system.

Further, in the embodiment of the present invention, when the radio parameter or the like is "configured" or "defined", a predetermined value is pre-configured in the base station 20 or the terminal 10. This may be the case, or it may be assumed that the base station 20 or the terminal 10 is pre-configured, or the radio parameter notified from the base station 20 or the terminal 10 is set. It may be set.

The base station 20 is a communication device that provides one or more cells and performs wireless communication with the terminal 10. The physical resources of the radio signal are defined in the time domain and the frequency domain, the time domain may be defined by the number of OFDM symbols (slots, subframes, symbols, time resources shorter than the symbols, etc.), and the frequency domain may be. It may be defined by the number of subcarriers or the number of resource blocks. The base station 20 transmits a synchronization signal and system information to the terminal 10. Synchronous signals are, for example, NR-PSS and NR-SSS. A part of the system information is transmitted by, for example, NR-PBCH, and is also referred to as broadcast information. The synchronization signal and the broadcast information may be periodically transmitted as an SS block (SS / PBCH block) composed of a predetermined number of OFDM symbols. For example, the base station 20 transmits a control signal or data to the terminal 10 by DL (Downlink), and receives the control signal or data from the terminal 10 by UL (Uplink). Both the base station 20 and the terminal 10 can perform beamforming to transmit and receive signals. For example, the reference signal transmitted from the base station 20 includes CSI-RS (Channel State Information Reference Signal), and the channels transmitted from the base station 20 are PDCCH (Physical Downlink Control Channel) and PDSCH (Physical Digital). including.

(RRC security mechanisms)
The outline of the RRC security procedure will be described below.

(RRC integrity mechanisms)
The integrity protection of the RRC is provided by the PDCP layer between the terminal 10 and the base station 20. Integrity protection is not applied to layers below PDCP.

When integrity protection is activated, replay protection is activated. In replay protection, the receiver can accept each received PDCP COUNT value only once when using the same AS security context.

NIA (New Radio Integrity algorithms) is a 5G integrity algorithm. The input parameters to the 128-bit NIA algorithm are "MESSAGE" as an RRC message, "K _RRCint " which is a 128-bit integrity key, "BEARER" which is a 5-bit bearer identifier, and "BEARER" which indicates the transmission direction with 1 bit. "DIRECTION" and "COUNT" (corresponding to 32-bit "PDCP COUNT"), which is a 32-bit input that depends on the bearer-specific direction.

The integrity check of RRC is performed on the base station 20 side and the terminal 10 side. If the integrity check detects an error, the associated message is discarded.

(RRC confidentiality mechanisms)
The RRC's confidentiality protection is provided by the PDCP layer between the terminal 10 and the base station 20.

NEA (New Radio Encryption Algorithms) is a 5G encryption algorithm. The input parameters to the 128-bit NEA algorithm are the 128-bit encryption key " _KRRCen ", the 5-bit bearer identifier "BEARER", the 1-bit "DIRECTION" indicating the transmission direction, and the required key stream length. "LENGTH" and "COUNT" (corresponding to 32-bit "PDCP COUNT") which is a 32-bit input depending on the direction peculiar to the bearer.

(Key layering)
FIG. 2 is a diagram showing an example of layering of keys used in NR. Keys associated with authentication include K, CK / IK. In the example shown in FIG. 2, the key hierarchy includes KAUSF, KSEAF, KAMF, KNASint, KNASenc, KN3IWF, KgNB, KRRCint, KRRCenc, KUPint, and KUPenc.

Here, KAUSF and KSEAF are the keys for AUSF (Authentication Server Function) in the home network. KAUSF is derived from CK and IK. KSEA is an anchor key derived from KAUSF.

KAMF is a key for AMF (Access and Mobility Management Function) of the serving network. KAMF is derived from KSEAF.

KNASint and KNASenc are the keys for NAS (Non Access Stratum) signaling. KNASint and KNASenc are derived from KAMF.

KgNB is a key for NG-RAN (Next Generation-Radio Access Network). KgNB is derived from KAMF. KgNB is used between the terminal 10 and the base station 20.

KUPenc and KUPint are the keys for uplink traffic. KUPenc and KUPint are derived from KgNB. KUPenc is only used to protect uplink traffic with cryptographic algorithms. KUPint is used only to protect the uplink traffic between the terminal 10 and the base station 20 by the integrity algorithm.

KRRCint and KRRCenc are the keys for RRC (Radio Resource Control) signaling. KRRCint and KRRCenc are derived from KgNB. KRRCint is only used to protect RRC signaling through integrity algorithms. KRRCenc is only used to protect RRC signaling by cryptographic algorithms.

FIG. 3 is a diagram showing an operation example of an encryption algorithm (ciphering algorithm). The input parameters for the encryption algorithm are 128-bit encryption key "KEY", 32-bit "COUNT", 5-bit bearer identifier "BEARER", 1-bit transmission direction "DIRECTION", and key stream. Includes "LENGTH" indicating the length of. In the case of uplink transmission, the bit of "DIRECTION" is 0, and in the case of downlink transmission, the bit of "DIRECTION" is 1.

FIG. 3 shows an example of an encryption algorithm NEA that encrypts plaintext by applying a keystream using bit-by-bit addition of plaintext and keystream. After being encrypted, the plaintext can be restored by generating the same keystream with the same input parameters and applying bit-by-bit binary addition to the ciphertext. Based on the input parameters, the algorithm generates an output keystream block KEYSTREAM, which is used to encrypt the input plaintext block PLAINIT, which produces the ciphertext block CIPHERTEXT. The input parameter "LENGTH" is used to adjust the length of the KEYSTREAM BLOCK.

FIG. 4 is a diagram showing an operation example of the integrity algorithm. The input parameters for the integrity algorithm are the 128-bit encryption key "KEY", the 32-bit "COUNT", the 5-bit bearer identifier "BEARER", the 1-bit transmission direction "DIRECTION", and the message itself. Includes "MESSAGE". In the case of uplink transmission, the bit of "DIRECTION" is 0, and in the case of downlink transmission, the bit of "DIRECTION" is 1. The bit length of "MESSAGE" is "LENGTH".

FIG. 4 shows an example of using the integrity algorithm NIA to authenticate the integrity of a message. Based on these input parameters, the sender uses the integrity algorithm NIA to calculate a 32-bit message authentication code (MAC-I / NAS-MAC). When sending a message, the message verification code is added to the message. In the case of the integrity protection algorithm, the receiver calculates the expected message authentication code (XMAC-I / XNAS-) based on the received message in the same way that the sender calculates the message authentication code based on the message sent by the sender. MAC) is calculated and the data integrity of the message is verified by comparing the expected message authentication code (XMAC-I / XNAS-MAC) with the received authentication code (MAC-I / NAS-MAC).

In the case of NR, as in the case of LTE, a stream encryption method is adopted for data encryption, in which the data and the key stream are encrypted by exclusive OR (XOR). In this method, it is important that the key stream is not reused. NEA, the NR encryption algorithm, only produces a finite length key stream. Therefore, in order to avoid reuse of the key stream, it is conceivable to change the key used for generating the key stream at an arbitrary timing, for example, at the time of handover.

(Key change on the fly)
"Key change on-the-fly" includes updating the key to the latest key (key refresh) or regenerating the key (re-keying). It is possible to apply "key refresh", which is a procedure for updating a key to the latest key, to KgNB, KRRC-enc, KRRC-int, KUP-enc, and KUP-int. Here, when a specific PDCP COUNT value is used again for the same bearer identifier and the same KgNB, "key refresh" is started by gNB / ng-eNB.

(About issues)
That is, in order to prevent the same COUNT value (that is, the same key stream) from being used twice for the transmission of data in the same bearer, the base station 20 is about to use the same COUNT value again. In this case, "key refresh" is performed. However, if the same COUNT value is about to be used again and the base station 20 does not perform "key refresh", the terminal 10 may use the same COUNT value again. If the same COUNT value (same key stream) is used more than once for the transmission of data in the same bearer, it is considered that the encrypted data is more likely to be decrypted by a third party. In other words, there is a high possibility that a third party will decrypt the key stream.

As one method, it is conceivable to specify a procedure for the terminal 10 to autonomously prevent the reuse of the same COUNT value without depending on the execution of "key refresh" by the base station 20.

FIG. 5 is a diagram showing an example of a procedure in which the terminal 10 autonomously prevents the reuse of the same COUNT value.

First, in step S101, the terminal 10 starts the data transmission procedure. In step S102, the terminal 10 sets the encryption key as an input parameter for the encryption algorithm applied to the transmission of data in a bearer, and sets the count value TX_NEXT to 0. In step S103, the terminal 10 receives the PDU (Packet Data Convergence Protocol) SDU (Service Data Unit) from the upper layer as the data to be transmitted.

In step S104, the terminal 10 associates the count value TX_NEXT with the PDCP SDU.

In step S105, the terminal 10 generates one or a plurality of PDCP PDUs (Protocol Data Units) corresponding to the PDCU SDU. In step S106, the terminal 10 applies the encryption key and the count value TX_NEXT to the encryption algorithm to encrypt one or more PDCP PDUs.

In step S107, the terminal 10 increments the count value TX_NEXT by 1.

In step S108, the terminal 10 determines whether or not the count value TX_NEXT is 0. If the terminal 10 determines in step S108 that the count value TX_NEXT is not 0, the process proceeds to step S109. The terminal 10 transmits one or more PDCP PDUs encrypted in step S109. If the terminal 10 determines in step S108 that the count value TX_NEXT is 0, the process proceeds to step S111. That is, even if the base station 20 side does not activate the encryption key update process, the terminal 10 autonomously advances the process to step S111.

In step S111, the terminal 10 activates the RRC connection re-establishment procedure. Specifically, the terminal 10 transmits an RRC Request request message to the base station 20. The base station 20 transmits an RRCRestation message to the terminal 10 in response to receiving the RRCReestivalRequest message from the terminal 10. When the terminal 10 receives the RRC Recovery message, the terminal 10 updates the encryption key used for transmitting the data.

After the terminal 10 updates the encryption key, the process proceeds to step S102. In step S102, the terminal 10 inputs the updated encryption key and the count value TX_NEXT = 0 as input parameters for the encryption algorithm applied to the transmission of data.

After transmitting one or more PDCP PDUs encrypted in step S109, the process proceeds to step S110. In step S110, the terminal 10 determines whether or not the next PDCP SDU has been received from the upper layer. If it is determined by the terminal 10 that the next PDCP SDU has been received from the upper layer in step S110, the process proceeds to step S104. After that, the terminal 10 performs the above-mentioned processing on the next PDCP SDU. If the terminal 10 determines in step S110 that the next PDCP SDU has not been received from the upper layer, the process proceeds to step S112, and the data transmission process ends.

According to the above processing, when data is transmitted by the same bearer, even if the base station 20 side does not start the encryption key update processing when the count value TX_NEXT = 0 is about to be reused. , The terminal 10 can update the encryption key by activating the procedure of RRC connection re-station. Even if the network does not perform security key refresh and the same COUNT value may be reused for the transmission of data to which the same encryption key is applied by the same bearer, the terminal 10 performs the reconnection process. By autonomously executing the above, it is possible to prevent the reuse of the COUNT value by closing the terminal 10 regardless of the operation of the network.

(Alt.1)
As shown in FIG. 5, the terminal 10 manages the COUNT value and transmits (or receives) data using the same cipher key and the same bearer. In this case, when the COUNT value is wrapped around, that is, when the same COUNT value is about to be reused, the terminal 10 may activate the procedure of RRC connection re-establishment.

Alt. In the case of 1, the following contents may be specified in the specifications. An independent counter (COUNTER) is maintained at the terminal 10 for each radio bearer and each transmission direction. For each radio bearer, COUNTER is used as an input parameter for encryption and integrity algorithms. It is not permissible for the same COUNT value to be used twice for the same bearer and the same encryption key. When it is necessary to update the encryption key, for example, when changing the Master Node accompanied by the change of KgNB, or when preventing the COUNT from going around, the procedure for updating the encryption key is applied. When the COUNT value has cycled for the same bearer and the same encryption key, the terminal 10 activates the RRC connection re-establishment.

(Alt.2)
Since the COUNT value starts from 0, by transmitting data (or receiving data) using the same encryption key and using the same bearer, the COUNT value is wrapped around and the COUNT value is rounded. When "0" is about to be reused, the terminal 10 may activate the procedure of RRC connection re-establishment.

(Alt.3)
When data is transmitted (or data is received) using the same encryption key and the same bearer, when the COUNT value reaches the maximum value, the terminal 10 is set to the RRC connection re-establishment. You may initiate the procedure. Here, the COUNT value may be represented by 32 bits, and the maximum value of the COUNT value may be 2∧32-1. When the COUNT value is represented by another number of bits, the COUNT value may be the maximum value among the numerical values that can be represented by the other number of bits.

(Alt.4)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, the terminal when the COUNT value first reaches the specific COUNT value specified in the specifications. 10 may activate the procedure of RRC connection re-establishment.

(Alt.5)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, the COUNT value is set by the base station 20 (for example, by RRC signaling). When the value is first reached, the terminal 10 may activate the RRC connection re-establishment procedure.

(Alt.6)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, and the COUNT value is wrapped around the number of times specified in the specifications, the terminal 10 May initiate the RRC connection re-establishment procedure.

(Alt.7)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, the COUNT value goes around the number of times set by the base station 20 (for example, by RRC signaling). In the case of (wrap around), the terminal 10 may activate the procedure of RRC connection re-establishment.

(Alt.8)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, when the specific COUNT value specified in the specifications is used twice (for example, specific). When the value is "2" and the COUNT value has been wrapped around and reached "2" again), the terminal 10 may activate the procedure of RRC connection re-establishment.

(Alt.9)
When data is transmitted (or data is received) using the same encryption key and with the same bearer, when the base station 20 uses the specific COUNT value set by RRC signaling twice ( For example, when the specific value is "2", the COUNT value goes round (wrap around) and reaches "2" again), the terminal 10 may activate the procedure of RRC connection re-establishment. ..

In the above embodiment, a cipher algorithm and a cipher key are mainly used. However, the examples are not limited to the above-mentioned examples. For example, in the above-described embodiment, the integrity algorithm may be used instead of the encryption algorithm, and the integrity key may be used instead of the encryption key.

(Device configuration)
Next, a functional configuration example of the terminal 10 and the base station 20 that execute the processing operations described so far will be described. The terminal 10 and the base station 20 have all the functions described in the present embodiment. However, the terminal 10 and the base station 20 may have only a part of all the functions described in the present embodiment.

<Terminal>
FIG. 6 is a diagram showing an example of the functional configuration of the terminal 10. As shown in FIG. 6, the terminal 10 has a transmitting unit 110, a receiving unit 120, and a control unit 130. The functional configuration shown in FIG. 6 is only an example. Any function classification and name of the functional unit may be used as long as the operation according to the present embodiment can be executed.

The transmission unit 110 creates a transmission signal from the transmission data and wirelessly transmits the transmission signal. The receiving unit 120 wirelessly receives various signals and acquires a signal of a higher layer from the received signal of the physical layer. Further, the receiving unit 120 includes a measuring unit that measures the received signal and acquires the received power and the like.

The control unit 130 controls the terminal 10. The function of the control unit 130 related to transmission may be included in the transmission unit 110, and the function of the control unit 130 related to reception may be included in the reception unit 120.

For example, the control unit 130 of the terminal 10 sets a bearer for transmitting one or a plurality of data units to the base station 20, and converts each data unit of the one or a plurality of data units into one or a plurality of packets. In the case of dividing and sequentially transmitting the divided one or a plurality of packets, a count value for sequentially counting the number of transmitted data units is maintained, and each data unit among the one or a plurality of data units is subjected to. When transmitting the corresponding one or more packets, at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key are specified as input parameters for the one or more packets. The key stream calculated by the algorithm of may be applied to encrypt the one or more packets. Further, the transmission unit 110 of the terminal 10 may transmit one or more packets to the base station 20 by the bearer described above. Further, the control unit 130 is the data to be transmitted first among the data units whose specific count value is one or more assigned to the data unit to be transmitted first among one or a plurality of data units. When it is detected that it is applied to a data unit other than the unit, the reconnection procedure regarding the connection with the base station 20 may be activated. The reconnection procedure may be an RRC connection re-establishment procedure.

For example, when the receiving unit 120 of the terminal 10 is sequentially transmitted from the base station in a bearer in which each data unit of one or a plurality of data units is divided into one or a plurality of packets, the receiving unit 120 is said to be the same from the base station 20. Each data unit of one or more data units transmitted in the bearer may be received. When the control unit 130 of the terminal 10 maintains a count value for counting the number of received data units and receives one or a plurality of packets corresponding to each data unit among the one or a plurality of data units. , At least the bearer's identifier, the count value corresponding to the data unit, and the key stream calculated by the specific algorithm are applied to the one or more packets as input parameters. , The one or more packets may be decrypted. The control unit 130 has a specific count value assigned to the first received data unit among the one or more data units other than the first received data unit among the one or more data units. When it is detected that it is applied to the reception of the data unit of, the reconnection procedure regarding the connection with the base station 20 may be activated. The reconnection procedure may be an RRC connection re-establishment procedure.

<Base station 20>
FIG. 7 is a diagram showing an example of the functional configuration of the base station 20. As shown in FIG. 7, the base station 20 includes a transmission unit 210, a reception unit 220, and a control unit 230. The functional configuration shown in FIG. 7 is only an example. Any function classification and name of the functional unit may be used as long as the operation according to the present embodiment can be executed.

The transmission unit 210 includes a function of generating a signal to be transmitted to the terminal 10 side and transmitting the signal wirelessly. The receiving unit 220 includes a function of receiving various signals transmitted from the terminal 10 and acquiring information of, for example, a higher layer from the received signals. Further, the receiving unit 220 includes a measuring unit that measures the received signal and acquires the received power and the like.

The control unit 230 controls the base station 20. The function of the control unit 230 related to transmission may be included in the transmission unit 210, and the function of the control unit 230 related to reception may be included in the reception unit 220.

For example, when the receiving unit 220 of the base station 20 is sequentially transmitted from the terminal 10 in a bearer in which each data unit of one or a plurality of data units is divided into one or a plurality of packets, the receiving unit 220 is said to be the same from the terminal 10. Each data unit of one or more data units transmitted in the bearer may be received. When the control unit 230 of the base station 20 maintains a count value for counting the number of received data units and receives one or a plurality of packets corresponding to each data unit among the one or a plurality of data units. , At least the bearer's identifier, the count value corresponding to the data unit, and the key stream calculated by the specific algorithm are applied to the one or more packets as input parameters. , The one or more packets may be decrypted. When the receiving unit 220 receives the request for the reconnection procedure regarding the connection with the terminal 10 transmitted from the terminal 10, the control unit 230 may execute the reconnection procedure. The reconnection procedure may be an RRC connection re-establishment procedure.

For example, the control unit 230 of the base station 20 sets a bearer for transmitting one or a plurality of data units to the terminal 10, and each data unit of the one or a plurality of data units is converted into one or a plurality of packets. In the case of dividing and sequentially transmitting the divided one or a plurality of packets, the count value for sequentially counting the number of transmitted data units is maintained, and each data unit of the one or a plurality of data units is supported. When transmitting one or more packets, at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key are used as input parameters for the one or more packets. The key stream calculated by the algorithm may be applied to encrypt the one or more packets. Further, the transmission unit 210 of the base station 20 may transmit one or a plurality of encrypted packets to the terminal 10 by the bearer described above. When the receiving unit 220 receives the request for the reconnection procedure regarding the connection with the terminal 10 transmitted from the terminal 10, the control unit 230 may execute the reconnection procedure. The reconnection procedure may be an RRC connection re-establishment procedure.

<Hardware configuration>
The block diagrams (FIGS. 6 to 7) used in the description of the above-described embodiment show blocks of functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Further, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically connected, or directly or indirectly (for example, by two or more devices that are physically or logically separated). , Wired, wireless, etc.) and may be realized using these plurality of devices. The functional block may be realized by combining the software with the one device or the plurality of devices. Functions include judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, selection, establishment, comparison, assumption, expectation, and assumption. Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but limited to these I can't. For example, a functional block (component) that functions transmission is called a transmitting unit or a transmitter. As described above, the method of realizing each of them is not particularly limited.

Further, for example, the terminal 10 and the base station 20 in one embodiment of the present invention may both function as computers that perform processing according to the present embodiment. FIG. 8 is a diagram showing an example of the hardware configuration of the terminal 10 and the base station 20 according to the present embodiment. The terminal 10 and the base station 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like. ..

In the following explanation, the word "device" can be read as a circuit, device, unit, etc. The hardware configuration of the terminal 10 and the base station 20 may be configured to include one or more of the devices shown in 1001 to 1006 shown in the figure, or may be configured not to include some of the devices. May be good.

For each function of the terminal 10 and the base station 20, the processor 1001 performs calculations by loading predetermined software (programs) on hardware such as the processor 1001 and the memory 1002, and controls communication by the communication device 1004. It is realized by controlling at least one of reading and writing of data in the memory 1002 and the storage 1003.

Processor 1001 operates, for example, an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU: Central Processing Unit) including an interface with a peripheral device, a control device, an arithmetic unit, a register, and the like.

Further, the processor 1001 reads a program (program code), a software module, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above-described embodiment is used. For example, the control unit 130 of the terminal 10 may be realized by a control program stored in the memory 1002 and operating in the processor 1001, and may be realized in the same manner for other functional blocks. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. Processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunication line.

The memory 1002 is a computer-readable recording medium, and is composed of at least one such as a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), and a RAM (Random Access Memory). May be done. The memory 1002 may be referred to as a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, or the like that can be executed to implement the wireless communication method according to the embodiment of the present disclosure.

The storage 1003 is a computer-readable recording medium, and is, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, an optical magnetic disk (for example, a compact disk, a digital versatile disk, or a Blu-ray). It may consist of at least one (registered trademark) disk), smart card, flash memory (eg, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. The storage 1003 may be referred to as an auxiliary storage device. The storage medium described above may be, for example, a database, server or other suitable medium containing at least one of the memory 1002 and the storage 1003.

The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like. The communication device 1004 includes, for example, a high frequency switch, a duplexer, a filter, a frequency synthesizer, and the like in order to realize at least one of frequency division duplex (FDD: Frequency Division Duplex) and time division duplex (TDD: Time Division Duplex). It may be composed of. For example, the transmission unit 110, the reception unit 120, and the like described above may be realized by the communication device 1004. Further, the transmitting unit 110 and the receiving unit 120 may be physically or logically separated from each other.

The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

Further, each device such as the processor 1001 and the memory 1002 is connected by the bus 1007 for communicating information. The bus 1007 may be configured by using a single bus, or may be configured by using a different bus for each device.

In addition, the terminal 10 and the base station 20 are hardware such as a microprocessor, a digital signal processor (DSP: Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), respectively. It may be configured to include hardware, and a part or all of each functional block may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these hardware.

(Summary of embodiments)
This specification discloses at least the following terminals and communication methods.

A bearer for transmitting one or more data units is set in the base station, each data unit of the one or more data units is divided into one or a plurality of packets, and the divided one or a plurality of data units are divided. When sequentially transmitting packets, maintaining a count value that sequentially counts the number of data units to be transmitted, and transmitting one or more packets corresponding to each data unit among the one or a plurality of data units. A key stream calculated by a specific algorithm is applied to the one or more packets with at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters. The control unit includes a control unit that encrypts the one or more packets, and a transmission unit that transmits the encrypted one or more packets to the base station by the bearer. Of the one or more data units, the specific count value assigned to the first transmitted data unit is the data unit other than the first transmitted data unit of the one or more data units. A terminal that activates a reconnection procedure for a connection with the base station when it detects that it applies to.

According to the above configuration, when data is transmitted by the same bearer, when the COUNT value 0 is about to be reused, the terminal can be used even if the base station does not update the encryption key. By invoking the reconnection procedure, it is possible to update the encryption key. By autonomously executing the reconnection process, the terminal can be closed to the terminal to prevent the reuse of the COUNT value regardless of the operation of the network.

When each data unit of one or a plurality of data units is sequentially transmitted from a base station in a bearer divided into one or a plurality of packets, one or a plurality of data transmitted from the base station in the bearer. A receiving unit that receives each data unit among the units and a count value that sequentially counts the number of the received data units are maintained, and one or one corresponding to each data unit among the one or a plurality of data units. When receiving a plurality of packets, for the one or more packets, at least the bearer identifier, the count value corresponding to the data unit, and a specific encryption key are used as input parameters and calculated by a specific algorithm. The control unit includes a control unit that applies the key stream to be decrypted and decodes the one or more packets, and the control unit receives the first data unit among the one or a plurality of data units. When it is detected that the assigned specific count value is applied to the reception of a data unit other than the first received data unit among the one or more data units, the data unit with the base station is contacted. The terminal that initiates the reconnection procedure for the connection.

According to the above configuration, when data is received by the same bearer, the terminal can be used even if the base station does not update the encryption key when the COUNT value 0 is about to be reused. By invoking the reconnection procedure, it is possible to update the encryption key. By autonomously executing the reconnection process, the terminal can be closed to the terminal to prevent the reuse of the COUNT value regardless of the operation of the network.

The control unit transmits the specific count value assigned to the first transmitted data unit of the one or more data units to the first of the one or more data units. When it is detected that the data unit is applied to the data unit other than the data unit and the base station does not activate the encryption key update procedure, the reconnection procedure regarding the connection with the base station is activated. You may.

According to the above configuration, when data is received by the same bearer, the COUNT value 0 is about to be reused, and the base station does not start the encryption key update process. Perform the reconnect procedure. When the base station activates the encryption key update process, the terminal can update the encryption key by the update process.

The control unit may update the encryption key when it receives a signal from the base station instructing reconnection related to the connection.

According to the above configuration, the terminal can autonomously update the encryption key.

The control unit may activate the reconnection procedure when the count value reaches the maximum value or the minimum value.

According to the above configuration, the terminal can prevent the COUNT value from being reused when transmitting data with the same bearer.

A bearer for transmitting one or more data units is set in the base station, each data unit of the one or more data units is divided into one or more packets, and the divided one or more data units are divided. When transmitting packets sequentially, maintaining a count value that sequentially counts the number of data units to be transmitted, and transmitting one or more packets corresponding to each data unit among the one or a plurality of data units. A key stream calculated by a specific algorithm is applied to the one or more packets with at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters. The step of encrypting the one or more packets and the step of transmitting the encrypted one or more packets to the base station by the bearer.
Of the one or more data units, the specific count value assigned to the first transmitted data unit is the data unit other than the first transmitted data unit of the one or more data units. A method of communication by a terminal comprising a step of invoking a reconnection procedure relating to a connection with the base station when it is detected that the application is applied to.

(Supplement to the embodiment)
Although the embodiments of the present invention have been described above, the disclosed inventions are not limited to such embodiments, and those skilled in the art can understand various modifications, modifications, alternatives, substitutions, and the like. There will be. Although explanations have been given using specific numerical examples in order to promote understanding of the invention, these numerical values are merely examples and any appropriate value may be used unless otherwise specified. The classification of items in the above description is not essential to the present invention, and items described in two or more items may be used in combination as necessary, and items described in one item may be used in combination with another item. It may be applied (as long as there is no contradiction) to the matters described in. The boundary of the functional unit or the processing unit in the functional block diagram does not always correspond to the boundary of the physical component. The operation of the plurality of functional units may be physically performed by one component, or the operation of one functional unit may be physically performed by a plurality of components. Regarding the processing procedure described in the embodiment, the processing order may be changed as long as there is no contradiction. For convenience of processing description, the terminal 10 and the base station 20 have been described with reference to functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of the terminal 10 according to the embodiment of the present invention and the software operated by the processor of the base station 20 according to the embodiment of the present invention are random access memory (RAM), flash memory, and read-only memory, respectively. It may be stored in (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

The notification of information is not limited to the mode / embodiment described in the present disclosure, and may be performed by using other methods. For example, information notification includes physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, etc. It may be carried out by notification information (MIB (Master Information Block), SIB (System Information Block)), other signals, or a combination thereof. Further, the RRC signaling may be called an RRC message, and may be, for example, an RRC connection setup (RRC Connection Setup) message, an RRC connection reconfiguration (RRC Connection Reconfiguration) message, or the like.

Each aspect / embodiment described in the present disclosure includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), and 5G (5th generation mobile communication). system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)) )), LTE 802.16 (WiMAX®), LTE 802.20, UWB (Ultra-WideBand), Bluetooth®, and other systems that utilize suitable systems and have been extended based on these. It may be applied to at least one of the next generation systems. Further, a plurality of systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A and 5G).

The order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in the present disclosure may be changed as long as there is no contradiction. For example, the methods described in the present disclosure present elements of various steps using exemplary order, and are not limited to the particular order presented.

In some cases, the specific operation performed by the base station 20 in the present disclosure may be performed by its upper node. In a network consisting of one or more network nodes having a base station 20, various operations performed for communication with a terminal are performed by the base station 20 and other network nodes other than the base station 20 (for example,). , MME, S-GW, etc., but not limited to these). Although the case where there is one network node other than the base station 20 is illustrated above, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

The input / output information and the like may be stored in a specific location (for example, memory) or may be managed using a management table. Input / output information and the like can be overwritten, updated, or added. The output information and the like may be deleted. The input information or the like may be transmitted to another device.

The determination may be made by a value represented by 1 bit (0 or 1), by a boolean value (Boolean: true or false), or by comparing numerical values (for example, a predetermined value). It may be done by comparison with the value).

Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched with execution. Further, the notification of predetermined information (for example, the notification of "being X") is not limited to the explicit one, but is performed implicitly (for example, the notification of the predetermined information is not performed). May be good.

Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, is an instruction, instruction set, code, code segment, program code, program, subprogram, software module. , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc. should be broadly interpreted.

Further, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, the software uses at least one of wired technology (coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL: Digital Subscriber Line), etc.) and wireless technology (infrared, microwave, etc.) to create a website. When transmitted from a server, or other remote source, at least one of these wired and wireless technologies is included within the definition of transmission medium.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these. It may be represented by a combination of.

Note that the terms explained in the present disclosure and the terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Also, the signal may be a message. Further, the component carrier (CC: Component Carrier) may be referred to as a carrier frequency, a cell, a frequency carrier, or the like.

The terms "system" and "network" used in this disclosure are used interchangeably. In addition, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, relative values from predetermined values, or using other corresponding information. It may be represented. For example, the radio resource may be one indicated by an index.

The names used for the above parameters are not limited in any respect. Further, mathematical formulas and the like using these parameters may differ from those explicitly disclosed in this disclosure. Since the various channels (eg, PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements are in any respect limited names. is not it.

In this disclosure, "base station (BS: Base Station)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " "Access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "cell group" Terms such as "carrier" and "component carrier" can be used interchangeably. Base stations are sometimes referred to by terms such as macrocells, small cells, femtocells, and picocells.

The base station can accommodate one or more (for example, three) cells. When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, each smaller area being a base station subsystem (eg, a small indoor base station (RRH:)). Communication services can also be provided by Remote Radio Head). The term "cell" or "sector" refers to part or all of the coverage area of at least one of the base stations and base station subsystems that provide communication services in this coverage. Point to.

In the present disclosure, terms such as "mobile station (MS: Mobile Station)", "user terminal", "user device (UE: User Equipment)", and "terminal" may be used interchangeably. ..

Mobile stations can be used by those skilled in the art as subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless. It may also be referred to as a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, or the like. At least one of the base station and the mobile station may be a device mounted on the mobile body, the mobile body itself, or the like. The moving body may be a vehicle (for example, a car, an airplane, etc.), an unmanned moving body (for example, a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned type). ) May be. It should be noted that at least one of the base station and the mobile station includes a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

Further, the base station in the present disclosure may be read by the user terminal. For example, communication between a base station and a user terminal has been replaced with communication between a plurality of user terminals (for example, it may be referred to as D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). Each aspect / embodiment of the present disclosure may be applied to the configuration. In this case, the terminal 10 may have the function of the base station 20 described above. In addition, words such as "up" and "down" may be read as words corresponding to communication between terminals (for example, "side"). For example, the upstream channel, the downstream channel, and the like may be read as a side channel. Similarly, the user terminal in the present disclosure may be read as a base station. In this case, the base station 20 may have the functions of the terminal 10 described above.

The terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or connection between two or more elements, and each other. It can include the presence of one or more intermediate elements between two "connected" or "combined" elements. The connections or connections between the elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in the present disclosure, the two elements use at least one of one or more wires, cables and printed electrical connections, and, as some non-limiting and non-comprehensive examples, the radio frequency domain. Can be considered to be "connected" or "coupled" to each other using electromagnetic energy having wavelengths in the microwave and light (both visible and invisible) regions.

The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

The phrase "based on" as used in this disclosure does not mean "based on" unless otherwise stated. In other words, the statement "based on" means both "based only" and "at least based on".

When used in the present disclosure are "include," "include," and variants thereof, these terms are as comprehensive as the term "comprising." Is intended. Furthermore, the term "or" used in the present disclosure is intended not to be an exclusive OR.

In the present disclosure, if articles are added by translation, for example, a, an and the in English, the disclosure may include that the nouns following these articles are plural.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other". The term may mean that "A and B are different from C". Terms such as "separate" and "combined" may be interpreted in the same way as "different".

Although the present invention has been described in detail above, it is clear to those skilled in the art that the present invention is not limited to the embodiments described in the present specification. The present invention can be implemented as modifications and modifications without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description of the present specification is for the purpose of exemplification and does not have any limiting meaning to the present invention.

10 Terminal 110 Transmitter 120 Receiver 130 Control 20 Base station 210 Transmitter 220 Receiver 230 Control 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device

Claims

A bearer for transmitting one or more data units is set in the base station, each data unit of the one or more data units is divided into one or more packets, and the divided one or more data units are divided. When transmitting packets sequentially, maintaining a count value that sequentially counts the number of data units to be transmitted, and transmitting one or more packets corresponding to each data unit among the one or a plurality of data units. A key stream calculated by a specific algorithm is applied to the one or more packets with at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters. And a control unit that encrypts the one or more packets,
A transmitter that transmits the encrypted one or more packets to the base station by the bearer.
With
In the control unit, the specific count value assigned to the data unit to be transmitted first among the one or more data units is the data to be transmitted first among the one or more data units. When it is detected that it is applied to a data unit other than the unit, the reconnection procedure regarding the connection with the base station is started.
Terminal.
When each data unit of one or a plurality of data units is sequentially transmitted from a base station in a bearer divided into one or a plurality of packets, one or a plurality of data transmitted from the base station in the bearer. A receiver that receives each data unit of the units,
When maintaining a count value that sequentially counts the number of received data units and receiving one or more packets corresponding to each data unit among the one or a plurality of data units, the one or a plurality of packets are received. A key stream calculated by a specific algorithm is applied to a packet using at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters, and the one or more of the packets are applied. A control unit that decodes packets and
With
In the control unit, the specific count value assigned to the first received data unit among the one or more data units is the first received data among the one or more data units. When it is detected that it is applied to the reception of a data unit other than the unit, the reconnection procedure regarding the connection with the base station is activated.
Terminal.
The control unit transmits the specific count value assigned to the first transmitted data unit of the one or more data units to the first of the one or more data units. When it is detected that the data unit is applied to the data unit other than the data unit and the base station does not activate the encryption key update procedure, the reconnection procedure regarding the connection with the base station is activated. ,
The terminal according to claim 1.
When the control unit receives a signal from the base station instructing reconnection regarding the connection, the control unit updates the encryption key.
The terminal according to claim 1 or 2.
The control unit activates the reconnection procedure when the count value reaches the maximum value or the minimum value.
The terminal according to claim 1 or 2.
A bearer for transmitting one or more data units is set in the base station, each data unit of the one or more data units is divided into one or more packets, and the divided one or more data units are divided. When transmitting packets sequentially, maintaining a count value that sequentially counts the number of data units to be transmitted, and transmitting one or more packets corresponding to each data unit among the one or a plurality of data units. A key stream calculated by a specific algorithm is applied to the one or more packets with at least the bearer's identifier, the count value corresponding to the data unit, and a specific encryption key as input parameters. And the step of encrypting the one or more packets,
The step of transmitting the encrypted one or more packets to the base station by the bearer, and
Of the one or more data units, the specific count value assigned to the first transmitted data unit is the data unit other than the first transmitted data unit of the one or more data units. The step of invoking the reconnection procedure for the connection with the base station when it is detected that it applies to
Communication method by a terminal equipped with.