JP2008197706A - Authentication apparatus, device to be authenticated, and battery authentication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an authentication apparatus capable of authenticating a device to be authenticated, without having a connection terminal exclusively for authentication, and of reducing the risk that falsifying the device to be authenticated becomes easy; a device to be authenticated; and a battery authentication system. <P>SOLUTION: When a communication part 28 is made to make communication for purposes other than an authentication process, a changeover switch 23 is used to connect a connection terminal 203 with the communication part 28 and communication is made by the communication part 28 using connection terminals 202, 203. When the process for authenticating a battery pack 3 is performed using an authentication IC 22, the changeover switch 23 is used to connect the connection terminal 203 with the authentication IC 22 and communication is made by the authentication IC 22 via the connection terminal 203 to perform the authentication process; also, a signal for camouflage is output by the communication part 28 to the connection terminal 202. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device to be authenticated, an authentication device that performs authentication, and a battery authentication system that authenticates a battery pack.

  In recent years, battery-powered devices such as portable personal computers and mobile phones that are driven using a battery pack that incorporates a rechargeable secondary battery have become widespread, and battery packs used in such battery-driven devices. Many are also commercially available. However, there are many companies that manufacture such battery packs without fraud or permission, and the quality of battery packs manufactured by such companies is often poor. Therefore, it is an issue to determine whether or not a battery pack is manufactured improperly, and to prevent secondary batteries from being damaged or causing a disaster when such a battery pack is charged. It has become.

  Therefore, the charging device for charging the battery pack has an authentication function for authenticating whether or not the battery pack is genuine by an authentication method known as so-called challenge and response authentication. Techniques for preventing the pack from being used are known. Further, an integrated circuit for authentication having such an authentication function is commercially available from a semiconductor manufacturer, and an authentication device such as the above-described charging device or an authentication target device such as the above-described battery pack is to be authenticated. A manufacturer purchases an integrated circuit for authentication from a semiconductor manufacturer and incorporates the integrated circuit into an authentication device such as a charging device or a device to be authenticated such as a battery pack, whereby the device can have an authentication function. .

  FIG. 5 is a conceptual diagram showing an outline of the configuration of the authentication circuit 101 used in the authentication apparatus as described above and the authentication target circuit 102 used in the authentication apparatus. The authentication circuit 101 and the to-be-authenticated circuit 102 shown in FIG. 5 are authentication integrated circuits manufactured by, for example, a semiconductor manufacturer, and are authentication circuits that perform so-called challenge and response authentication. The authentication circuit 101 and the circuit to be authenticated 102 store the same encryption key 103, respectively. Then, the authentication circuit 101 generates a random number 104 and transmits it as a challenge to the circuit to be authenticated 102.

  Next, the random number 104 transmitted as a challenge from the authentication circuit 101 to the authenticated circuit 102 is encrypted by the authenticated circuit 102 using the encryption key 103 and transmitted as a response to the authentication circuit 101. On the other hand, the authentication circuit 101 generates the verification data 105 by encrypting the random number 104 using the encryption key 103 by the same encryption method as that of the circuit to be authenticated 102. Then, the verification data 105 is compared with the response transmitted from the circuit 102 to be authenticated, and if they match, it is determined that the authentication is successful, and if they do not match, the authentication process is determined to be executed. .

  Therefore, the authentication device including the authentication circuit 101 and the authentication target device including the authentication target circuit 102 include an interface circuit for transmitting and receiving the above-described challenge and response. FIG. 6 is a block diagram illustrating an example of the configuration of the authentication system 110 including the charging device 111 and the battery pack 112 according to the background art. The charging device 111 illustrated in FIG. 6 includes an authentication circuit 101, an MPU (Microprocessing Unit) 113, a charging circuit 114, resistors 115 and 116, and connection terminals 121, 122, 123, 124, and 125. A battery pack 112 illustrated in FIG. 6 includes a circuit to be authenticated 102, a secondary battery 131, a control circuit 132, a switching element 133, and connection terminals 141, 142, 143, 144, and 145.

  Further, when the battery pack 112 is attached to the charging device 111, the connection terminals 121, 122, 123, 124, 125 and the connection terminals 141, 142, 143, 144, 145 are connected.

  The communication method between the charging device 111 and the battery pack 112 is a two-wire communication method that uses a synchronous clock SCL and a data signal SDA by the battery standard organization SBS-IF (Smart Battery System Implementers Forum). A certain SMBus (System Management Bus) (registered trademark) is standardized, and the MPU 113 and the control circuit 132 connect the connection terminals 122 and 142 and the connection terminals 123 and 143 by such a two-wire communication method. Communication is enabled through the network.

  Then, the terminal voltage and charging current of the secondary battery 131 detected by the control circuit 132 by the voltage detection circuit (not shown) and the current detection circuit (not shown) are connected to the connection terminals 122 and 142 and the connection terminal 123 by the control circuit 132. , 143, and the MPU 113 adjusts the output current of the charging circuit 114 according to the terminal voltage and charging / discharging current of the secondary battery 131 transmitted from the control circuit 132 by the MPU 113, and the secondary battery 131 appropriately. Is charged.

  In addition, the authentication circuit 101 and the circuit to be authenticated 102 not only have the encryption method kept secret in order to prevent forgery, but also makes it difficult to analyze the authentication method, In many cases, the communication protocol between the authentication circuit 101 and the circuit to be authenticated 102 is also kept secret. As described above, when the bit length of the challenge and the communication protocol between the authentication circuit 101 and the circuit to be authenticated 102 are kept secret, the authentication circuit 101 and the circuit to be authenticated 102 are incorporated into the device and used. The manufacturer cannot know the communication protocol between the authentication circuit 101 and the circuit to be authenticated 102.

  For this reason, the device manufacturer directly connects the authentication circuit 101 and the circuit to be authenticated 102, so that a challenge or response can be transmitted and received between the authentication circuit 101 and the circuit to be authenticated 102. 124 and 144 are provided. In this way, by providing the connection terminals 124 and 144 dedicated for encryption authentication, the authentication circuit 101 and the circuit to be authenticated 102 can be connected even if the device manufacturer does not know the communication protocol between the authentication circuit 101 and the circuit to be authenticated 102. However, the authentication circuit 101 can authenticate the battery pack 112 by performing direct communication via the connection terminals 124 and 144. The MPU 113 can authenticate the battery pack 112 by receiving only the authentication result obtained by the authentication circuit 101 from the authentication circuit 101.

  However, if the charging device 111 as the authentication device and the battery pack 112 as the device to be authenticated are provided with connection terminals dedicated for encryption authentication, the cost increases due to the increase in the number of connection terminals, and the market However, if the connection terminal 144 dedicated for encryption authentication is provided in an apparatus to be authenticated such as the battery pack 112 that is strongly demanded for downsizing, there is a disadvantage that downsizing is hindered.

Therefore, it is considered that the connection terminals used for communication between the MPU 113 and the control circuit 132 are shared for communication between the authentication circuit 101 and the circuit to be authenticated 102, thereby reducing the connection terminals dedicated to cryptographic authentication. (For example, refer to Patent Document 1).
JP 2003-162986 A

  However, as described above, since communication between the charging device 111 and the battery pack 112 is performed by SMBus (registered trademark), which is a two-wire communication method, two wires between the MPU 113 and the control circuit 132 are used. When communication is performed between the MPU 113 and the control circuit 132 when the connection terminals 123 and 143, for example, of the connection terminals used for the type communication are shared for communication between the authentication circuit 101 and the circuit to be authenticated 102 In other words, a signal flows through both the connection terminals 122 and 142 and the connection terminals 123 and 143, whereas when authentication is performed between the authentication circuit 101 and the circuit to be authenticated 102, a signal is transmitted only to the connection terminals 124 and 144. Not flowing. Therefore, a third party who tries to counterfeit the authenticated circuit 102 has a signal flowing through both the connection terminals 122 and 142 and the connection terminals 123 and 143, or the connection terminals 122 and 142 and the connection terminals 123 and 143 Since it becomes easy to specify an authentication signal transmitted / received between the authentication circuit 101 and the circuit to be authenticated 102 depending on whether a signal flows through only one of them, the authentication signal is analyzed. As a result, the battery pack 112 can be easily forged.

  The present invention has been made in view of such circumstances, and authenticates an authenticated device without providing an authentication-dedicated connection terminal to an authentication device including an authentication circuit and an authenticated device including an authenticated circuit. An object of the present invention is to provide an authentication device, an authentication target device, and a battery authentication system that can be performed and can reduce the possibility of facilitating forgery of the authentication target device.

  An authentication apparatus according to the present invention is an authentication apparatus that performs authentication of an authentication target apparatus to be authenticated, and includes at least one of a plurality of connection terminals for connecting to the authentication target apparatus and the plurality of connection terminals. Between the changeover switch connected to one first connection terminal and the device to be authenticated, the remaining second connection terminal excluding the first connection terminal among the plurality of connection terminals, the changeover switch, and the changeover By performing communication between the communication unit that communicates with each of the switches via the first connection terminal and the authentication target device via the changeover switch and the first connection terminal, When the communication is performed by the authentication processing unit that performs authentication processing of the authentication device and the communication unit, the first connection terminal and the communication unit are connected by the changeover switch, and the authentication processing unit When performing authentication processing, the switching switch connects the first connection terminal and the authentication processing unit by the switch, and the communication processing unit outputs a camouflaging signal to the second connection terminal; Is provided.

  According to this configuration, when the communication unit performs a communication process different from the authentication process with the device to be authenticated, the first connection terminal and the communication unit are connected by the changeover switch. Communication with the device to be authenticated is performed via the first and second connection terminals. Further, when communication for authentication processing is performed by the authentication processing unit, the first connection terminal and the authentication processing unit are connected by the changeover switch, and the authentication target device is connected to the device to be authenticated via the first connection terminal. Communication for authentication processing is performed, and a camouflaged signal is output from the communication unit to the second connection terminal. In this case, since communication for authentication processing is performed via the first connection terminal used for communication processing different from the authentication processing, it is not necessary to provide the authentication device with a connection terminal dedicated for authentication. Further, during the authentication process, a camouflaged signal is output from the communication unit to the second connection terminal that is not used for communication for the authentication process, so depending on whether or not a signal is flowing to the second connection terminal. As a result, it becomes difficult to distinguish whether or not the signal is an authentication signal, and it becomes difficult to analyze the authentication signal. As a result, it is possible to reduce the possibility that the device to be authenticated can be easily counterfeited.

  The first connection terminal, the changeover switch, and the second connection terminal are each one, and the communication unit transmits a data signal to the authentication target device via the changeover switch and the first connection terminal. And a synchronous signal is transmitted by transmitting a clock signal to the device to be authenticated via the second connection terminal, and the switching processing unit transmits the signal as a camouflaged signal by the communication unit. It is preferable to output the clock signal.

  According to this configuration, when communication different from the authentication process is performed by the communication unit, a data signal is transmitted to the device to be authenticated through the first connection terminal, and to the device to be authenticated through the second connection terminal. A clock signal is transmitted, and synchronous communication is executed. When the authentication process is performed, the communication unit outputs the same clock signal to the second connection terminal as a signal for impersonation when communication different from the authentication process is performed. Due to the flowing signal, it becomes difficult to distinguish whether the signal flowing through the first connection terminal is an authentication signal, and it becomes difficult to analyze the authentication signal. Can be reduced. Since the clock signal used for synchronous communication is a simple periodic signal, the same signal is generated when communication for authentication processing is performed and when communication processing other than authentication processing is performed. Easy to do.

  The authentication processing unit transmits predetermined authentication data used for the authentication to the device to be authenticated via the changeover switch and the first connection terminal, and is transmitted from the device to be authenticated. A reception unit that receives the received reply data via the first connection terminal and the changeover switch, an encryption key storage unit that stores the encryption key for authentication in advance, and the authentication data An encryption unit that generates encrypted data by encrypting using the encryption key stored in the encryption key storage unit, the encrypted data generated by the encryption unit, The reply data received by the receiving unit is compared, and if the encrypted data and the reply data match, a signal indicating that the authentication has succeeded is output, and the encrypted data and the reply data match. If not, it is preferably provided with an authentication unit that outputs a signal indicating that authentication has failed.

  According to this configuration, when authentication processing is performed by the authentication processing unit, transmission is performed in parallel with output of a signal for impersonation from the communication unit to the second connection terminal that is not used for communication for authentication processing. The authentication data is transmitted to the device to be authenticated through the first connection terminal by the unit, and the reply data transmitted from the device to be authenticated through the first connection terminal is received by the reception unit. Depending on whether or not the signal is flowing, it becomes difficult to distinguish the authentication data and the reply data from signals other than the authentication signal, and it becomes difficult to analyze the authentication data and the reply data. It is possible to reduce the possibility of facilitating forgery.

  In addition, the device to be authenticated according to the present invention is a device to be authenticated that is authenticated by the above-described authentication device, and includes a first authenticated side connection terminal for connecting to the first connection terminal, and the second connection terminal. A second authenticated side connection terminal for connecting to the first authenticated side connection terminal, an authenticated side communication unit that communicates with the communication unit via the first authenticated side connection terminal and the second authenticated side connection terminal, 1 An authentication response processing unit that responds to an authentication process by the authentication processing unit by performing communication with the authentication device via an authentication target connection terminal.

  According to this configuration, the authenticated-side communication unit communicates with the communication unit in the above-described authentication device via the first authenticated-side connection terminal and the second authenticated-side connection terminal, and the authentication response processing unit Since the authentication processing by the authentication processing unit is performed by responding to the authentication processing by the authentication processing unit via the first authenticated side connection terminal, it is not necessary to provide the authentication target device with a connection terminal dedicated for authentication. In addition, during the authentication process, a signal for impersonation is output from the communication unit to the second connection terminal that is not used for communication for the authentication process and the second authenticated terminal connected to the second connection terminal. Therefore, it becomes difficult to distinguish whether the signal flowing through the first authenticated side connection terminal is an authentication signal depending on whether the signal is flowing through the second authenticated side connection terminal. As a result, it becomes difficult to analyze this signal, and the possibility that the device to be authenticated can be easily counterfeited can be reduced.

  In addition, the device to be authenticated is a battery pack further provided with a secondary battery, and the authentication-side communication unit transmits a signal related to the secondary battery to the first authenticated-side connection terminal and the second authenticated device. It is preferable to transmit to the said communication part via a side connection terminal.

  According to this configuration, it is possible to reduce the risk of facilitating the forgery of the battery pack without providing the authentication dedicated connection terminal in the battery pack including the secondary battery. Moreover, the signal regarding a secondary battery can be transmitted to a communication part via a 1st to-be-authenticated side connection terminal and a 2nd to-be-authenticated side connection terminal by the to-be-authenticated side communication part.

  The battery authentication system according to the present invention includes the authentication device described above and the device to be authenticated, and the authentication device includes a connection terminal for charging for connecting to the secondary battery, and the communication unit. The charging device further includes a charging unit that charges the secondary battery via the charging connection terminal in response to a signal received from the battery pack via the first and second connection terminals.

  According to this configuration, the communication unit acquires a signal indicating information related to the secondary battery of the battery pack via the first and second connection terminals, and the secondary battery is charged by the charging unit according to the signal. be able to. In addition, since it is difficult to analyze the authentication signal without providing the authentication dedicated connection terminal in the battery pack as the device to be authenticated and the charging device as the authentication device, the battery pack may be easily forged. Can be reduced.

  The authentication device, the device to be authenticated, and the battery authentication system configured as described above are connected to the first connection terminal by the changeover switch when the communication unit performs a communication process different from the authentication process with the device to be authenticated. A communication unit is connected, and the communication unit communicates with the device to be authenticated through the first and second connection terminals. Further, when communication for authentication processing is performed by the authentication processing unit, the first connection terminal and the authentication processing unit are connected by the changeover switch, and the authentication target device is connected to the device to be authenticated via the first connection terminal. Communication for authentication processing is performed, and a camouflaged signal is output from the communication unit to the second connection terminal. In this case, since communication for authentication processing is performed via the first connection terminal used for communication processing different from the authentication processing, it is not necessary to provide the authentication device with a connection terminal dedicated for authentication. Further, during the authentication process, a camouflaged signal is output from the communication unit to the second connection terminal that is not used for communication for the authentication process, so depending on whether or not a signal is flowing to the second connection terminal. As a result, it becomes difficult to distinguish whether or not the signal is an authentication signal, and it becomes difficult to analyze the authentication signal. As a result, it is possible to reduce the possibility that the device to be authenticated can be easily counterfeited.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram showing an example of a configuration of a battery authentication system using an authentication device and an authentication target device according to an embodiment of the present invention. A battery authentication system 1 shown in FIG. 1 includes a charging device 2 that is an example of an authentication device, and a battery pack 3 that is an example of a device to be authenticated.

  The charging device 2 includes a control IC (Integrated Circuit) 21, an authentication IC 22 (authentication processing unit), a changeover switch 23, a charging circuit 24 (charging unit), resistors 25 and 26, a connection terminal 201 (charging connection terminal), a connection A terminal 202 (second connection terminal), a connection terminal 203 (first connection terminal), and a connection terminal 204 are provided. The control IC 21 includes a control unit 27 and a communication unit 28. The battery pack 3 includes a secondary battery 31, an IC to be authenticated 32 (authentication response processing unit), a control IC 33, a changeover switch 34, a switching element 38, a connection terminal 301, a connection terminal 302 (second authenticated side connection terminal), a connection A terminal 303 (first authenticated connection terminal) and a connection terminal 304 are provided. The control IC 33 includes a control unit 35, a communication unit 36 (authenticated side communication unit), and a voltage detection circuit 37.

  When the charging device 2 and the battery pack 3 are combined, the connection terminals 201, 202, 203, and 204 are connected to the connection terminals 301, 302, 303, and 304, respectively.

  First, in the charging device 2, the change-over switch 23 is configured using, for example, a switching element such as a semiconductor analog switch, a multiplexer, a photo MOS relay, a transistor, a relay switch, and the like, and according to a control signal from the control unit 27. The connection terminal 203 is selectively connected to either the communication unit 28 or the authentication IC 22. The resistor 25 is a pull-up resistor of the connection terminal 202, and the resistor 26 is a pull-up resistor of the connection terminal 203.

  The communication unit 28 is, for example, a two-wire communication interface circuit that conforms to the SMBus (registered trademark) standard. The communication unit 28 transmits the clock signal SCL for synchronization to the communication unit 36 via the connection terminals 202 and 302, converts the signal from the control unit 27 into a serial signal, and changes the data signal SDA as a changeover switch. 23, the connection terminal 203, 303, and the changeover switch 34 are transmitted to the communication unit 36, or the data signal SDA transmitted from the communication unit 36 is transmitted via the changeover switch 34, the connection terminals 303, 203, and the changeover switch 23. Or converted into a signal format that can be processed by the control unit 27 and transmitted to the control unit 27.

  The charging circuit 24 includes, for example, an AC-DC converter, a DC-DC converter, and the like, and uses a power supply voltage supplied from an unillustrated power supply circuit as a voltage value, a current value, and a pulse corresponding to a control signal from the control unit 27. The width is converted and supplied to the battery pack 3 via the connection terminals 201 and 301 and the connection terminals 204 and 304.

  FIG. 2 is a block diagram showing an example of the configuration of the authentication IC 22 and the authentication target IC 32. First, the configuration of the authentication IC 22 will be described. For example, the authentication IC 22 generates a random number as the authentication data D1, outputs the random number generation circuit 221 to the transmission unit 222, and the authentication data D1 (challenge) from the random number generation circuit 221 as the data signal SDA. 23 and a receiving unit that receives the reply data D3 (response) transmitted from the battery pack 3 via the connection terminal 203 and the changeover switch 23. 223, an encryption key storage unit 224 configured using, for example, an EEPROM (Electrically Erasable and Programmable Read Only Memory) that stores an encryption key for authentication in advance, and authentication data D1 by a preset encryption method Generate encrypted data D2 by encrypting using the encryption key stored in the encryption key storage unit 224. The encryption unit 225 is configured by a comparator, for example, and the encrypted data D2 is compared with the reply data D3 received by the receiver 223. When the encrypted data D2 and the reply data D3 match, authentication is performed. The authentication unit 226 outputs an authentication result signal D4 indicating success and outputs an authentication result signal D4 indicating that the authentication has failed when the encrypted data D2 and the reply data D3 do not match.

  Returning to FIG. 1, the control unit 27 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores a predetermined control program, and a RAM that temporarily stores data. (Random Access Memory) and these peripheral circuits and the like, and functions as a switching processing unit 271 and a charging control unit 272 by executing a control program stored in the ROM.

  When the communication unit 28 performs communication, the switching processing unit 271 connects the connection terminal 203 and the communication unit 28 with the changeover switch 23, and when the authentication IC 22 performs authentication processing, the switching processing unit 271 connects with the changeover switch 23. The terminal 203 and the authentication IC 22 are connected, and the communication unit 28 transmits a synchronization clock signal SCL to the battery pack 3 via the connection terminal 202.

  The charging control unit 272 controls the output voltage, current, and the like of the charging circuit 24 based on the signal received from the battery pack 3 by the communication unit 28.

  Next, in the battery pack 3, the connection terminal 301 is connected to the positive electrode of the secondary battery 31 through the switching element 38. The connection terminal 304 is connected to the negative electrode of the secondary battery 31 and used as a ground terminal.

  The voltage detection circuit 37 is configured using, for example, an A / D converter, detects the terminal voltage of the secondary battery 31, converts it into a digital signal, and outputs it to the control unit 35.

  Similar to the communication unit 28, the communication unit 36 is a two-wire communication interface circuit compliant with, for example, the SMBus (registered trademark) standard. Then, the communication unit 36 synchronizes with the synchronization clock signal SCL received from the communication unit 28 via the connection terminals 202 and 302 and from the communication unit 28 via the connection terminals 203 and 303 and the changeover switch 34. The received data signal SDA is received, converted into a signal format that can be processed by the control unit 35, and output to the control unit 35. In addition, the communication unit 36 converts the signal output from the control unit 35 into a serial signal to be a data signal SDA, and is synchronized with the clock signal SCL to the charging device 2 via the changeover switch 34 and the connection terminals 303 and 203. Output.

  Returning to FIG. 2, the IC for authentication 32 includes, for example, a reception unit 321, an encryption key storage unit 322, an encryption unit 323, and a transmission unit 324. The reception unit 321 is a communication interface circuit that receives the authentication data D1 transmitted from the charging device 2 via the connection terminals 203 and 303 and the changeover switch 34 and outputs the data to the encryption unit 323.

  The encryption key storage unit 322 is a non-volatile storage circuit configured using, for example, an EEPROM, and stores the same encryption key as the encryption key stored in the encryption key storage unit 224 in advance. The encryption unit 323 encrypts the authentication data D1 received by the reception unit 321 using the encryption key stored in the encryption key storage unit 322, using the same encryption method as the encryption unit 225. As a result, reply data D3 is generated and output to the transmission unit 324.

  The transmission unit 324 transmits the reply data D3 as the data signal SDA to the charging device 2 via the changeover switch 34 and the connection terminals 303 and 203.

  As described above, the transmission unit 222 and the reception unit 321 and the transmission unit 324 and the reception unit 223 are directly connected by the changeover switches 23 and 34 and the connection terminals 203 and 303. The manufacturer that manufactures the IC 22 and the IC 32 to be authenticated is used between the transmission unit 222 and the reception unit 321 and between the transmission unit 324 and the reception unit 223 by the device manufacturer that manufactures the charging device 2 and the battery pack 3. Since the communication method is kept secret, it is possible to improve the difficulty of analyzing the encryption method used in the authentication IC 22 and the IC 32 to be authenticated. As a result, the forgery of the battery pack 3 can be improved.

  Note that the authentication processing unit and the authentication response processing unit are not limited to those integrated into an integrated circuit such as the authentication IC 22 or the authentication target IC 32, and are circuit modules configured on a printed wiring board, for example. Also good.

  Returning to FIG. 1, the control unit 35 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores a predetermined control program, and a RAM that temporarily stores data. (Random Access Memory) and these peripheral circuits and the like, and functions as a switching control unit 351 and a charge / discharge control unit 352 by executing a control program stored in the ROM.

  When the authentication control is performed by the IC to be authenticated 32, for example, when the communication unit 36 receives a signal indicating that the authentication process is to be performed from the charging device 2, the switch control unit 351 is connected to the connection terminal 303 by the switch 34. Are connected to the IC 32 for authentication. When the communication is performed by the communication unit 36, for example, when the switch control unit 351 receives a signal indicating that the transmission of the reply data D3 is completed from the IC 32 to be authenticated, the switch control unit 351 is connected to the connection terminal 303 by the switch 34. The communication unit 36 is connected.

  The charge / discharge control unit 352 causes the communication unit 36 to transmit information indicating the terminal voltage of the secondary battery 31 detected by the voltage detection circuit 37 to the charging device 2. The charge / discharge control unit 352 further includes, for example, information indicating the charging current of the secondary battery 31 detected by a current sensor (not shown) and the temperature of the secondary battery 31 detected by a temperature sensor (not shown). You may make it transmit to the charging device 2 by the communication part 36. FIG. Alternatively, the charge / discharge control unit 352 may cause the communication unit 36 to transmit instruction information such as a voltage, a current, or a pulse width for requesting the output to the charging circuit 24 to the charging device 2. The charge / discharge control unit 352 detects overvoltage, overcurrent, excessive temperature rise, and the like based on information such as voltage, current, and temperature detected by the voltage detection circuit 37 and a current sensor or temperature sensor (not shown). In this case, the switching element 38 is turned off to protect the secondary battery 31 from overvoltage, overcurrent, excessive temperature rise, and the like.

  Next, the operation of the battery authentication system 1 configured as described above will be described. FIG. 3 is a flowchart showing an example of the operation of the battery authentication system 1. First, in response to a control signal from the switching processing unit 271, the communication unit 28 transmits a signal indicating that an authentication process is performed to the communication unit 36 in the battery pack 3. When the communication unit 36 receives a signal indicating that the authentication process is to be performed, the switch control unit 351 switches the switch 34 to the IC for authentication 32 side (step S1).

  Next, the switch 23 of the charging device 2 is switched to the authentication IC 22 side by the switching processing unit 271 (step S2). As a result, the authentication IC 22 and the authentication target IC 32 are connected via the changeover switch 23, the connection terminals 203 and 303, and the changeover switch 34, and an authentication process is executed between the authentication IC 22 and the authentication target IC 32. Made possible.

  Next, the disguise clock signal SCL is transmitted from the communication unit 28 to the battery pack 3 through the connection terminal 202 by the switching processing unit 271 by, for example, a method of transmitting dummy data from the communication unit 28. (Step S3). Then, the authentication data D1 is transmitted from the authentication IC 22 to the authentication target IC 32 via the connection terminals 203 and 303, and the reply data D3 is returned from the authentication IC 32 to the authentication IC 22 via the connection terminals 303 and 203. Thus, the authentication process is executed (step S4).

  Specifically, in the authentication IC 22, the random number generation circuit 221 generates a random number as the authentication data D1 and outputs it to the transmission unit 222. The transmission unit 222 converts the authentication data D1 (challenge) as the data signal SDA. Then, the data is transmitted to the IC for authentication 32 via the changeover switch 23, the connection terminals 203 and 303, and the changeover switch 34.

  Then, the authentication data D1 is received by the receiving unit 321 and output to the encryption unit 323 in the IC 32 to be authenticated. Then, the encryption unit 323 encrypts the authentication data D1 using the encryption key stored in the encryption key storage unit 322 by the same encryption method as that of the encryption unit 225, whereby the reply data D3 is obtained. Generated. Then, the reply data D3 is transmitted by the transmission unit 324 to the reception unit 223 of the authentication IC 22 via the changeover switch 34, the connection terminals 303 and 203, and the changeover switch 23.

  In the authentication IC 22, the authentication data D 1 generated by the random number generation circuit 221 is encrypted by the encryption unit 225 using the encryption key stored in the encryption key storage unit 224 by a preset encryption method. The encrypted data D2 is generated. Then, the authentication unit 226 compares the encrypted data D2 and the reply data D3 received by the receiver 223, and if the encrypted data D2 and the reply data D3 match, an authentication result signal indicating that the authentication has been successful. When D4 is output to the control unit 27 and the encrypted data D2 and the reply data D3 do not match, an authentication result signal D4 indicating that the authentication has failed is output to the control unit 27.

  In this case, while the authentication data D1 is being transmitted from the authentication IC 22 to the authentication target IC 32 via the connection terminals 203 and 303, and from the authentication IC 32 to the authentication IC 22 via the connection terminals 303 and 203. While the data D3 is being transmitted, two-wire communication between the communication unit 28 and the communication unit 36 is performed on the connection terminals 202 and 302 that are not used for communication between the authentication IC 22 and the IC for authentication 32. Since the same clock signal SCL is output as when the operation is executed, whether a third party who is trying to forge the battery pack 3 flows through both the connection terminals 202 and 302 and the connection terminals 203 and 303. The authentication data D1 and the reply data D3, which are authentication signals transmitted and received between the authentication IC 22 and the IC to be authenticated 32, can be specified depending on whether or not It can not result, it is possible to reduce the possibility of analyzing the encryption used in the authentication becomes difficult, it becomes easy to counterfeit battery pack 3.

  Further, according to the above-described configuration, since the authentication target device can be authenticated without providing the connection device dedicated to encryption authentication in the charging device 2 and the battery pack 3, it is possible to reduce the increase in cost and reduce the battery. The risk of facilitating forgery of the pack 3 can be reduced.

  Next, when the transmission of the reply data D3 by the IC for authentication 32 is completed, for example, a signal indicating that the transmission of the reply data D3 is completed is transmitted from the IC for authentication 32 to the switching control unit 351. The changeover switch 34 of the battery pack 3 is switched to the communication unit 36 side (step S5).

  Next, when the authentication result signal D4 output from the authentication IC 22 is confirmed by the switching processing unit 271 (step S6) and the authentication result signal D4 indicates an authentication failure (NO in step S6), the clock by the communication unit 28 Transmission of the signal SCL is stopped (step S7), and the process is terminated. On the other hand, if the authentication result signal D4 indicates successful authentication in step S6 (YES in step S6), transmission of the clock signal SCL by the communication unit 28 is stopped (step S8), and the switching processing unit 271 causes the charging device 2 to The changeover switch 23 is switched to the communication unit 28 side so that the communication unit 28 and the communication unit 36 can execute two-wire communication (step S9).

  Information indicating the terminal voltage of the secondary battery 31 detected by the voltage detection circuit 37 by the charge / discharge control unit 352, the charging current of the secondary battery 31 detected by a current sensor (not shown), and the temperature (not shown). A signal indicating information related to the secondary battery 31 such as information indicating the temperature of the secondary battery 31 detected by the sensor is output to the communication unit 36 and transmitted from the communication unit 36 to the communication unit 28. Further, the charging control unit 272 controls the output voltage, current, and the like of the charging circuit 24 based on information such as the terminal voltage, charging current, and temperature of the secondary battery 31 received from the battery pack 3 by the communication unit 28. The battery 31 is charged (step S10), and the process ends.

  The charging / discharging control unit 352 transmits an instruction signal for instructing a charging voltage, a charging current, a charging pulse width, and the like for charging the secondary battery 31 to the charging device 2 as a signal related to the secondary battery, and charging control is performed. The unit 272 may cause the charging circuit 24 to output a charging voltage, a charging current, a charging pulse width, and the like according to the instruction signal transmitted from the charging / discharging control unit 352.

  The charging device 2 includes connection terminals 202 and 203 for performing two-wire serial communication, the connection terminal 203 corresponds to an example of a first connection terminal, and the connection terminal 202 is an example of a second connection terminal. Although a corresponding example is shown, a plurality of first and second connection terminals may be provided. FIG. 4 is an explanatory diagram illustrating an example of a method of connecting the control units 27a and 35a and the authentication ICs 22a and 32a when a plurality of first and second connection terminals are provided.

  As shown in FIG. 4, the control unit 27a and the control unit 35a communicate with each other via, for example, an 8-bit parallel bus, and the authentication IC 22a and the IC for authentication 32a have, for example, a 4-bit parallel bus. It is also possible to perform communication via In this case, the bus interface circuit 273 included in the control unit 27a corresponds to an example of a communication unit, and the bus interface circuit 353 included in the control unit 35a corresponds to an example of an authenticated communication unit.

  For example, 4 bits of the 8-bit bus are connected to a connection terminal 203-1, which corresponds to an example of a first connection terminal via a plurality of changeover switches 23-1, 23-2, 23-3, 23-4, respectively. 203-2, 203-3, 203-4, the remaining 4 bits are connected to connection terminals 202-1, 202-2, 202-3, 202-4 corresponding to an example of the second connection terminal, By switching the selector switches 23-1, 23-2, 23-3, 23-4 in accordance with a control signal from the switching processing unit 271, either one of the control unit 27a and the authentication IC 22a is connected to the connection terminal. It is good also as a structure connected to the battery pack 3a via 202-1, 202-2, 202-3, 202-4.

  In this case, when the authentication processing of the battery pack 3 is performed by the authentication IC 22a, the switching processing unit 271 uses the changeover switches 23-1, 23-2, 23-3, 23-4 to connect the connection terminals 203-1, 203. -2, 203-3, 203-4 and the authentication IC 22a are connected to each other, and for example, by performing a data write operation preset by the bus interface circuit 273 or random, What is necessary is just to make it transmit the signal for camouflage to 202-2, 202-3, 202-4.

  Similarly, the battery pack 3a is connected to the connection terminals 202-1, 202-2, 202-3, 202-4 and the connection terminals 203-1, 203-2, 203-3, 203-4, respectively. It has connection terminals 302-1, 302-2, 302-3, 302-4 and connection terminals 303-1, 303-2, 303-3, 303-4, and switches 34-1, 34-2, 34. The control unit 35a and the IC for authentication 32a may be connected to the connection terminals 303-1, 303-2, 303-3, and 303-4 by -3 and 34-4.

  Moreover, the authentication apparatus should just be an apparatus which has an authentication function, and is not restricted to the charging device 2. FIG. The device to be authenticated only needs to be a device to be authenticated, and is not limited to the battery pack 3, and may be a memory card or various adapter devices, for example. The authentication device may be, for example, a portable personal computer, a digital camera, a mobile phone, or the like that incorporates the charging device 2, and is an electronic device that does not have a secondary battery charging function, such as a memory card or other various devices. It may be a device that performs authentication of the adapter device.

  The present invention relates to various types of adapter devices such as battery packs and memory cards used as a power source for various types of battery-mounted devices, and a device to be authenticated, a charging device that authenticates such a device to be authenticated, and a portable device It can be suitably used as an authentication device for electronic devices such as type personal computers, digital cameras, mobile phones, vehicles such as electric cars and hybrid cars, and an authentication system comprising such an authentication device and a device to be authenticated. .

It is a block diagram which shows an example of a structure of the battery authentication system using the authentication apparatus which concerns on one Embodiment of this invention, and a to-be-authenticated apparatus. It is a block diagram which shows an example of a structure of IC for authentication and IC for authentication shown in FIG. It is a flowchart which shows an example of operation | movement of the battery authentication system shown in FIG. It is explanatory drawing for demonstrating the modification of the battery authentication system shown in FIG. It is a conceptual diagram which shows the outline of a structure of the authentication circuit used incorporating in the authentication apparatus which concerns on background art, and the authentication target circuit used incorporating in a to-be-authenticated apparatus. It is a block diagram which shows an example of a structure of the authentication system which consists of a charging device and a battery pack which concern on background art.

Explanation of symbols

1 Battery Authentication System 2 Charging Device 3, 3a Battery Pack 22, 22a Authentication IC
23, 34 changeover switch 24 charging circuit 27, 27a, 35, 35a control unit 28, 36 communication unit 31 secondary battery 32, 32a IC for authentication
37 Voltage detection circuit 201, 202, 203, 204, 301, 302, 303, 304 Connection terminal 221 Random number generation circuit 222, 324 Transmission unit 223, 321 Reception unit 224 Encryption key storage unit 225, 323 Encryption unit 226 Authentication unit 271 Switching processing unit 272 Charging control unit 273, 353 Bus interface circuit 322 Encryption key storage unit 351 Switching control unit 352 Charge / discharge control unit D1 Authentication data D2 Encrypted data D3 Reply data D4 Authentication result signal SDA Data signal SCL Clock signal

Claims (6)

An authentication device that performs authentication of a device to be authenticated.
A plurality of connection terminals for connecting to the device to be authenticated;
A changeover switch connected to at least one first connection terminal of the plurality of connection terminals;
Among the plurality of connection terminals, a remaining second connection terminal excluding the first connection terminal, and the changeover switch and the first connection terminal connected to the changeover switch, respectively, with the device to be authenticated. A communication unit that communicates via
An authentication processing unit that performs authentication processing of the device to be authenticated by communicating with the device to be authenticated via the changeover switch and the first connection terminal;
When the communication unit performs the communication, the changeover switch connects the first connection terminal and the communication unit, and when the authentication processing unit performs the authentication process, the changeover switch causes the first connection terminal to communicate with the communication unit. An authentication apparatus comprising: a switching processing unit that connects one connection terminal and the authentication processing unit, and causes the communication unit to output a signal for camouflaging to the second connection terminal. The first connection terminal, the changeover switch, and the second connection terminal are each one,
The communication unit transmits a data signal to the device to be authenticated through the changeover switch and the first connection terminal, and transmits a clock signal to the device to be authenticated through the second connection terminal. Perform synchronous communication,
The authentication apparatus according to claim 1, wherein the switching processing unit causes the communication unit to output the clock signal as the camouflaged signal. The authentication processing unit
A transmitter that transmits predetermined authentication data used for the authentication to the device to be authenticated via the changeover switch and the first connection terminal;
A receiving unit that receives the reply data transmitted from the device to be authenticated via the first connection terminal and the changeover switch;
An encryption key storage unit that stores an encryption key for authentication in advance;
An encryption unit that generates encrypted data by encrypting the authentication data using an encryption key stored in the encryption key storage unit by a preset encryption method;
The encrypted data generated by the encryption unit is compared with the return data received by the reception unit, and if the encrypted data and the return data match, a signal indicating that the authentication is successful is output. The authentication apparatus according to claim 1, further comprising: an authentication unit that outputs a signal indicating that the authentication has failed when the encrypted data and the reply data do not match. A device to be authenticated that is authenticated by the authentication device according to claim 1,
A first authenticated connection terminal for connecting to the first connection terminal;
A second authenticated side connection terminal for connecting to the second connection terminal;
An authenticated-side communication unit that communicates with the communication unit via the first authenticated-side connection terminal and the second authenticated-side connection terminal;
An authentication target device comprising: an authentication response processing unit that responds to an authentication process by the authentication processing unit by performing communication with the authentication device via the first authenticated side connection terminal. The device to be authenticated is a battery pack further provided with a secondary battery,
The authentication-side communication unit transmits a signal related to the secondary battery to the communication unit via the first authenticated-side connection terminal and the second authenticated-side connection terminal. The device to be authenticated. The authentication device according to any one of claims 1 to 3,
A device to be authenticated according to claim 5,
The authentication device includes a connection terminal for charging for connecting to the secondary battery,
A charging device further comprising: a charging unit that charges the secondary battery via the charging connection terminal in response to a signal received from the battery pack via the first and second connection terminals by the communication unit. A battery authentication system characterized by

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