WO2022264564A1

WO2022264564A1 - Method for manufacturing security module

Info

Publication number: WO2022264564A1
Application number: PCT/JP2022/011002
Authority: WO
Inventors: 雅哉山本; 幸一森岡
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2021-06-14
Filing date: 2022-03-11
Publication date: 2022-12-22
Also published as: CN117426066A; JPWO2022264564A1

Abstract

Provided is a method for manufacturing a security module (10). The security module (10) holds a master key (12a) and an encrypted individual key (14a) obtained by encrypting an individual key by means of the master key (12a). The manufacturing method comprises: a first step (S33) for writing the master key (12a) into a write-once storage region of an IC when alone, the IC to be mounted in the security module (10); and a second step (S35) for writing the encrypted individual key (14a) into a write-many flash memory (14) which is to be implemented on a substrate together with the IC.

Description

Security module manufacturing method

The present disclosure relates to a method of manufacturing a security module.

In recent years, IoT (Internet of Things) technology has progressed, and IoT devices equipped with communication modules in white goods such as refrigerators, washing machines, and microwave ovens are connected to the Internet, making the use of white goods more convenient. Attempts are being made to

On the other hand, when IoT devices are connected to the Internet, there is a risk that attacks that cause the devices to malfunction will be carried out via the Internet, or information about the devices such as usage history will be wiretapped via the Internet.

Therefore, in order to realize safe Internet communication, IoT devices are considering encrypting and concealing data in communication via the Internet.

For example, Patent Literature 1 discloses a technique for generating a common key from a master key and a home appliance serial number, encrypting information using the generated common key, and communicating the information.

JP 2018-14640 A

By the way, it is being considered to install a security module that stores a master key and an encrypted individual key (encrypted individual key) in IoT devices. The master key is used to decrypt encrypted individual keys. Therefore, for example, if the master key is leaked, the encrypted individual key may be decrypted, so management of the master key is important. For example, even when the security module is manufactured, it is required to be managed so that the master key is not leaked. However, Patent Literature 1 does not disclose how to prevent the master key from being leaked when the security module is manufactured.

Therefore, the present disclosure provides a method of manufacturing a security module that can prevent the master key from being leaked during manufacturing of the security module.

A security module manufacturing method according to an aspect of the present disclosure is a manufacturing method for manufacturing a security module holding a master key and an encrypted individual key obtained by encrypting the individual key with the master key, wherein the security A first step of writing the master key in the state of the IC alone in a storage area that can be written only once in an IC (Integrated Circuit) mounted on the module; and a second step of writing the encrypted individual key into a memory that can be written once.

According to the security module manufacturing method according to one aspect of the present disclosure, it is possible to prevent the master key from being leaked during manufacturing of the security module.

FIG. 1 is a diagram showing the configuration of an IoT home appliance system according to an embodiment. FIG. 2 is a block diagram of the functional configuration of the security module according to the embodiment. FIG. 3 is a flow chart showing a method of encrypting an individual key. FIG. 4 is a diagram showing the configuration of an encrypted file containing an encrypted individual key issued by a key issuing authority. FIG. 5 is a flow chart showing a method of decrypting an encrypted individual key. FIG. 6 is a flow chart showing an example of a method for manufacturing the security module according to the embodiment. FIG. 7 is a diagram showing the configuration of the socket jig according to the embodiment. FIG. 8 is a table showing control procedures for writing a master key to a chip according to the embodiment. FIG. 9 is a flow chart showing another example of the security module manufacturing method according to the embodiment.

(Circumstances leading to this disclosure)
Prior to explaining the present disclosure, the circumstances leading to the present disclosure will be described.

As described in the "Background Art" above, the use of master keys is under consideration in order to encrypt and keep data confidential.

When a security module implemented with a general-purpose MPU (Micro Processor Unit) or the like is installed in an IoT home appliance, it is necessary to write a master key to the general-purpose MPU in the manufacturing process of the security module.

On the other hand, the security module manufacturing process includes multiple processes such as mounting and assembling, and the length of the manufacturing line for that purpose can be several tens of meters. In the manufacturing line, a plurality of workers work.

The inventors of the present application have found that in an environment where there are many workers in such a large space, it is difficult to sufficiently manage each worker, and there is a risk of leakage of firmware including the master key. I found a problem. The master key forms the basis of the security of IoT home appliances, and if it is leaked even once, it becomes difficult to ensure the security of communication. This is considered to be very important in ensuring safety in communication.

Therefore, the inventors of the present application conducted extensive research on a method of manufacturing a security module that can prevent the leakage of the master key during the manufacture of the security module, and devised the method of manufacturing the security module shown below.

As a result, the master key can be written in an easy-to-handle IC unit state, making it easier to limit the work space and operators for writing the master key. In other words, it becomes easier to manage workers who write the master key. Therefore, according to the method for manufacturing a security module according to an aspect of the present disclosure, it is possible to prevent the master key from being leaked by a worker or the like during manufacturing of the security module.

Also, for example, the second step may be performed in a manufacturing line for manufacturing the security module, and the first step may be performed in a dedicated security room isolated from the manufacturing line.

As a result, the security module manufacturing method according to one aspect of the present disclosure can be realized at low cost without making the entire security module manufacturing process a secure environment.

Further, for example, the second step may be performed in the state of the memory alone, and the memory in which the encryption individual key is written may be mounted on the substrate.

As a result, the individual encryption key can be written in a single memory that is easy to handle, making it easier to limit the work space and operators for writing the individual encryption key. In other words, it becomes easier to manage the operator who writes the encrypted individual key. Therefore, according to the method for manufacturing a security module according to an aspect of the present disclosure, it is possible to prevent leakage of the individual encryption key by a worker or the like during manufacturing of the security module.

Also, for example, the second step may be performed with the memory mounted on the substrate.

As a result, when a jig that performs writing in a single memory state does not have a function to write mutually different information (for example, an encryption individual key) to each of a plurality of memories, the memory is mounted on the board. The encryption individual key can be written later.

Further, for example, the encrypted individual key is further encrypted using an individual value unique to the security module, and in the second step, the individual value is further written into the memory, and is written into the memory. The method may further include a third step of writing the individual value to the storage area of the IC.

As a result, individual values can be easily written to the storage area of the IC via the memory.

Also, for example, the method may further include a fourth step of writing firmware to the memory for writing the individual value to the storage area of the IC.

As a result, individual values can be written to the storage area simply by activating the firmware.

Further, for example, the fourth step may be performed with the memory alone, and the memory in which the encrypted individual key and the individual value are written may be mounted on the substrate.

As a result, individual values can be written in a single memory that is easy to handle, making it easier to limit the work space and operators for writing individual keys. In other words, it becomes easier to manage workers who write individual keys. Therefore, according to the method for manufacturing a security module according to an aspect of the present disclosure, it is possible to prevent the individual key from being leaked by a worker or the like during manufacturing of the security module.

Further, for example, a fifth step of deleting the individual values written in the memory may be further included after the third step.

As a result, if the memory is a non-secure storage area, it is possible to prevent the individual value information from leaking out of the memory.

Also, for example, the IC has a secure zone and a non-secure zone, the master key is written in a storage area in the secure zone, and the encrypted individual key is stored in the non-secure zone. It may be written to a certain storage area.

As a result, since the master key is written to the storage area within the secure zone, it is possible to prevent the master key from being leaked due to, for example, access from the outside.

Also, for example, in the first step, a lock function that prohibits reading of the master key during processing in the non-secure zone may be turned on.

As a result, it is possible to prevent the master key from being leaked through processing in the non-secure zone.

Hereinafter, embodiments will be specifically described with reference to the drawings.

It should be noted that the embodiments described below are all comprehensive or show specific examples. Numerical values, shapes, components, arrangement positions of components, connection forms, steps (processes), order of steps (processes), etc. shown in the following embodiments are examples, and are intended to limit the present disclosure. is not. For example, numerical values are not expressions that express only strict meanings, but expressions that include a substantially equivalent range, for example, a difference of several percent. Further, among the constituent elements in the following embodiments, constituent elements not described in independent claims will be described as optional constituent elements.

In addition, each figure is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, scales and the like do not necessarily match in each drawing. Moreover, in each figure, the same code|symbol is attached|subjected about the substantially same structure, and the overlapping description is abbreviate|omitted or simplified.

Also, in this specification, terms indicating the relationship between elements such as the same, and numerical values and numerical ranges are not expressions that express only strict meanings, but substantially equivalent ranges, such as about several percent This expression means that a difference of (for example, about 5%) is also included.

(Embodiment)
A method of manufacturing a security module according to the present embodiment will be described below with reference to FIGS. 1 to 9. FIG.

[1. Configuration of IoT home appliance system]
First, the configuration of an IoT home appliance system including IoT home appliances equipped with a security module manufactured using the security module manufacturing method according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing the configuration of an IoT home appliance system according to this embodiment.

As shown in FIG. 1, in the IoT home appliance system, an IoT home appliance 1 can communicate with a cloud system 3 composed of a plurality of servers via the Internet 2.

The Internet 2 is an example of a network, and may be a telephone line or a LAN (Local Area Network).

An IoT home appliance 1 is a white goods such as a washing machine connected to the Internet 2 as shown in FIG. Note that the IoT home appliance 1 is not limited to white goods such as a washing machine connected to the Internet 2, and white goods such as a refrigerator or a microwave oven connected to the Internet 2 as described above. It's okay. The IoT home appliance 1 may be any home appliance that can be connected to the Internet 2 . Further, the communication destination of the IoT home appliance 1 is not limited to the cloud system 3, and may be, for example, a terminal device such as a smart phone.

In addition, the IoT home appliance 1 is equipped with a security module 10 for realizing secure Internet communication.

The configuration of the security module 10 will be described with reference to FIG. FIG. 2 is a block diagram showing the functional configuration of the security module 10 according to this embodiment.

As shown in FIG. 2, the security module 10 has an IC (Integrated Circuit) 15 and a flash memory 14. Also, the IC 15 includes a control unit 11 , a secure storage area 12 and a non-secure storage area 13 . The control unit 11, the secure storage area 12, and the non-secure storage area 13 are integrated into one chip.

The control unit 11 is an arithmetic processing unit that executes various processes in the security module 10.

The secure storage area 12 stores the master key 12a. The master key 12a is a master key used when encrypting an individual key in the key issuing authority, and is used in the security module 10 to decrypt the encrypted individual key 14a. The master key 12a is, for example, a key (common master key) common to each product. The secure storage area 12 is, for example, a storage area built into the IC 15 . The secure storage area 12 is identifiable by a memory address within the IC 15, for example.

The non-secure storage area 13 stores individual values 13a. The individual value 13a is a value used when encrypting the individual key in the key issuing authority, and is used in the security module 10 to decrypt the encrypted individual key 14a. The individual value 13a is, for example, a unique value for each product. The individual value 13a is, for example, a random value. For example, the individual value 13a may be an identification number (eg, serial number). The non-secure storage area 13 is, for example, a storage area built into the IC 15 . Non-secure storage area 13 can be identified, for example, by a memory address within IC 15 .

The flash memory 14 stores an encrypted individual key 14a. In other words, the encrypted individual key 14a is stored in a storage device separate from the IC 15. FIG. The encrypted individual key 14a is an individual key encrypted using the master key 12a and the individual value 13a. Also, the flash memory 14 has a larger storage capacity than the secure storage area 12 and the non-secure storage area 13, for example. The flash memory 14 is an example of memory.

The encrypted individual key 14a is not limited to using the individual value 13a as long as it is encrypted using at least the master key 12a. If the encrypted individual key 14a is generated by encrypting the individual key without using the individual value 13a, the security module 10 may not store the individual value 13a.

Also, the IC 15 has a secure zone and a non-secure zone (not shown).

The Secure Zone has a mechanism to prevent unauthorized access from the outside. In other words, the secure zone is a highly reliable arithmetic processing unit that is unlikely to be hacked.

The secure zone is connected to the secure storage area 12. In other words, the secure storage area 12 is a storage device for secure zones. Also, the secure storage area 12 is not connected to, for example, the non-secure zone. The security module 10 can also be said to hold the master key 12a in the secure zone.

For the secure storage area 12, for example, a non-volatile memory with a one-time write function, such as FUSE memory, is used. The FUSE memory may be, for example, an eFuse memory that stores data by electrically irreversibly changing element characteristics.

The security module 10 executes secure processing in the secure zone, which is an area under surveillance mode. That is, the security module 10 executes secure processing in a secure zone, which is a separate environment from non-secure processing. Access to the memory area or program code in the secure zone is restricted from the program code in the area outside the monitor mode.

As a result, the security module 10 can execute secure processing in the secure zone without being affected by security-related vulnerabilities in non-secure processing.

The non-secure zone is a normal arithmetic processing unit. For example, processing by operating system programs or processing by normal application programs are executed in the non-secure zone.

The non-secure zone is connected to the non-secure storage area 13. In other words, the non-secure storage area 13 is a storage device for the non-secure zone. It can also be said that the security module 10 holds an individual value 13a in the non-secure zone.

For the non-secure storage area 13, for example, a non-volatile memory with a one-time write function, such as FUSE memory, is used. The FUSE memory may be, for example, an eFuse memory that stores data by electrically irreversibly changing element characteristics.

Also, the non-secure zone and the secure zone may be connected to the flash memory 14. The flash memory 14 is a nonvolatile memory having a rewrite function. It can also be said that the security module 10 holds an encrypted individual key 14a in the non-secure zone. Also, the flash memory 14 may hold a firmware program executed by the control unit 11 and its setting data, in addition to the encrypted individual key 14a.

The security module 10 executes non-secure processing in a non-secure zone that is not a secure zone. In other words, since non-secure processing is executed in an area that is not a secure zone, there is a risk that malicious code or the like may be executed by exploiting vulnerabilities, that is, eavesdropping or tampering. For example, there is a risk that the encrypted individual key 14a will be leaked. However, even if the encrypted individual key 14a is leaked, if the master key 12a is not leaked, it is difficult to decrypt the encrypted individual key 14a, so the impact on security is small. For this reason as well, it is important to prevent leakage of the master key 12a.

Such a security module 10 is realized by mounting an IC 15, a flash memory 14, etc. on a substrate on which wiring and the like are formed. A general-purpose MPU, for example, is used for the IC 15 . The IC 15 functions, for example, as an information processing unit for performing communication with the cloud system 3 using an individual key. In addition, a communication module such as an antenna may be mounted on the security module 10, for example.

Note that the individual key is, for example, a private key for decrypting data encrypted by the public key corresponding to the individual key in the IoT home appliance 1, that is, a private key of the public key cryptosystem. It may be a common key for key cryptography.

It should be noted that the master key 12a according to the present embodiment does not include the hardwired logic embedded in the IC 15. In other words, in the security module 10 according to the present embodiment, it is necessary to write the master key 12a into the secure storage area 12 during manufacturing.

[2. Encryption and decryption of individual keys]
Next, the encryption processing and decryption processing of the individual key will be described with reference to FIGS. 3 to 5. FIG. FIG. 3 is a flow chart showing a method of encrypting an individual key. The processing shown in FIG. 3 is performed, for example, at the key issuing authority.

As shown in FIG. 3, first, a key (key encryption key) for encrypting the individual key is derived based on the master key 12a and the individual value 13a (S11). The method of deriving the key (key encryption key) using the master key 12a and the individual value 13a is exemplified by a method using a key derivation function (Key Derivation Function), but any other known method may be used. may

Next, the individual key is encrypted using the key generated in step S11 (S12). That is, in step S12, the encrypted individual key 14a is generated.

Next, the master key 12a, individual value 13a, and encrypted individual key 14a are output (S13). For example, a set of information including the master key 12a, the individual value 13a, and the encrypted individual key 14a is output to the security module 10 manufacturer.

FIG. 4 is a diagram showing the configuration of an encrypted file containing the encrypted individual key 14a (individual client private key in FIG. 4) issued by the key issuing authority. Since the master key 12a is common, FIG. 4 shows an example in which the key issuing authority issues information in which the encrypted individual key 14a and the individual value 13a (random value in FIG. 4) are set. there is The manufacturer of the security module 10 acquires, for example, the information shown in FIG. 4 from the key issuing authority. The manufacturer of the security module 10 also obtains the master key 12a from the key issuing authority.

The key issuing authority distributes the master key 12a, public key certificate, individual key (encrypted individual key 14a), individual value 13a, etc. to the manufacturer. The key issuing agency is provided outside the manufacturer of the security module 10 . The public key certificate contains information indicating the public key. A public key certificate includes, for example, but is not limited to, public key version, issuer, validity period, certificate identification information (ID), public key, and the like.

As shown in FIG. 4, the encrypted file includes multiple files including "File 1", "File 2" and "File 3". One file contains data corresponding to one product. For the file name, for example, the same character string as "serial value" may be used.

Each file contains an individual client private key (corresponding to the encrypted individual key 14a), an individual client certificate (corresponding to the public key certificate), and a random value (corresponding to the individual value 13a). In each of the files, the information is different from each other.

In this way, the individual key is supplied from the key issuing authority to the security module 10 manufacturer in an encrypted state.

The encrypted file is, for example, a ZIP file and is compressed, but is not limited to this.

Next, the method of decrypting the encrypted individual key 14a in the security module 10 will be described with reference to FIG. FIG. 5 is a flow chart showing a method of decrypting the encrypted individual key 14a.

As explained above, the IoT home appliance 1 and the cloud system 3 transmit and receive encrypted data. For example, when the IoT home appliance 1 acquires data encrypted with a public key in the cloud system 3, the process shown in FIG. 5 is executed.

As shown in FIG. 5, the control unit 11 derives a key (key encryption key) for decrypting the encrypted individual key 14a based on the master key 12a and the individual value 13a (S21). Then, the control unit 11 uses the key derived in step S21 to decrypt the encrypted individual key 14a (S22). That is, the control unit 11 generates an individual key based on the key derived in step S21 and the encrypted individual key 14a. In other words, the control unit 11 derives the key encryption key and uses the key encryption key to decrypt the encrypted individual key 14a, thereby obtaining the individual key (secret key). Any known method may be used to decrypt the encrypted individual key 14a using the master key 12a and the individual value 13a.

As a result, the control unit 11 can decrypt the encrypted information transmitted from the cloud system 3 using the decrypted individual key.

[3. Security module manufacturing method]
Next, a method of manufacturing the security module 10 configured as described above will be described with reference to FIGS. 6 to 9. FIG. FIG. 6 is a flow chart showing an example of a method for manufacturing the security module 10 according to this embodiment. FIG. 6 shows a manufacturing method for manufacturing the security module 10 holding the master key 12a and the encrypted individual key 14a, which is the individual key encrypted by the master key 12a. Note that the IC 15 is also referred to as a chip 15 below.

The manufacturer of the security module 10, for example, installs the IC 15 (for example, a general-purpose MPU) in a state in which the master key 12a and the individual value 13a are not stored in the secure storage area 12 and the non-secure storage area 13, respectively. Obtain from the manufacturer. Also, the manufacturer of the security module 10 acquires the encrypted file as shown in FIG. 4 and the master key 12a from the key issuing authority.

In other words, it is necessary to write the master key 12a obtained from the key issuing authority into the secure storage area 12 in the manufacturing process of the security module 10 according to the present embodiment. Leakage of the master key 12 a may also occur during the manufacturing process of the security module 10 . A method of manufacturing the security module 10 capable of suppressing leakage of the master key 12a in the manufacturing process of the security module 10 will be described below.

As shown in FIG. 6, first, in the method of manufacturing the security module 10, the chip 15 (IC chip) is obtained (S31). For example, the worker acquires IC15. In the manufacturing method of the security module 10 according to this embodiment, for example, a general-purpose MPU is obtained. At this point, the information of the master key 12a and the individual value 13a is not stored in the chip 15 (for example, general-purpose MPU).

Next, in the method of manufacturing the security module 10, a socket jig is prepared (S32), and the master key 12a is written into the chip 15 alone using the socket jig (S33). For example, an operator prepares a socket jig and writes the master key 12a into the chip 15 alone. That is, the master key 12a is written in the secure storage area 12 while the chip 15 is not mounted on the board.

Writing the master key 12a in the state of the chip 15 alone is an important part of the manufacturing method of the security module 10 according to the present embodiment. Since the chip 15 alone is easy to handle, the time required for writing the master key 12a is shortened as compared with the case where the master key 12a is written in the chip 15 mounted on the substrate while suppressing the leakage of the master key 12a. be able to. This is because the chip 15 mounted on the substrate is more complicated to carry and handle than the single chip 15 and requires a wider working space. As in the present embodiment, it is relatively easy to suppress the leakage of the master key 12a if there is only a minimum necessary work space.

Steps S32 and S33 are an example of the first step. The first step is to write the master key 12a in the state of the chip 15 alone in the secure storage area 12 (an example of a storage area that can be written only once) in the chip 15 (inside the IC 15) mounted on the security module 10. It can also be said that

It should be noted that steps S32 and S33 are preferably performed in a dedicated security room. In other words, the chip 15 obtained in step S31 may be temporarily transported to a dedicated security room. The dedicated security room is a dedicated space (for example, a dedicated room) for writing the master key 12a to the secure storage area 12, and is a space isolated from the space where the processes after step S34 are performed, for example. For example, the processes after step S34 may be performed in a manufacturing line for manufacturing the security module 10, and the processes of steps S32 and S33 may be performed in a dedicated security room isolated from the manufacturing line.

For example, the dedicated security room may be separated by a wall or the like from the space where the processes from step S34 onwards are performed. In addition, workers entering and exiting the dedicated security room are managed by surveillance cameras, an entry/exit system, and the like. A dedicated security room is, for example, a room in which a worker in the dedicated security room can be identified.

In addition, workers who can enter and leave the dedicated security room may be registered in advance. When an unregistered worker enters a dedicated security room, an alarm or the like may be issued to notify the operator. In addition, the number of workers and the number of workers in a dedicated security room may be managed by monitoring cameras, an entry/exit system, and the like. For example, if more than a predetermined number of workers are present in a dedicated security room, an alarm or the like may be used to inform them. Also, taking the socket jig out of the dedicated security room may be managed. For example, when a socket jig is taken out of a dedicated security room, an alarm or the like may be used to inform the user.

In this way, by writing the master key 12a in a dedicated security room, it becomes possible to easily manage workers, objects (for example, socket jigs), and the like. Also, since the master key 12a is written in the state of the IC 15 alone, the dedicated security room can be saved in space.

Here, the procedure for writing the master key 12a to the socket jig and the chip 15 will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 is a diagram showing the configuration of the socket jig 20 according to this embodiment.

As shown in FIG. 7, the socket jig 20 is a jig for writing the master key 12a to the chip 15 in the state of the chip 15 alone, that is, in the state in which the chip 15 is not mounted on the substrate. The socket jig 20 has three writing units 30 and a power supply unit 40 . Note that the number of writing units 30 included in the socket jig 20 is not particularly limited as long as it is one or more.

The writing unit 30 is a component for writing the master key 12a to the chip 15, and has a flash memory 31, a socket 32, and a light emitting unit 33.

The flash memory 31 stores write firmware (for example, OTP write firmware) for writing the master key 12a to the chip 15 . For example, the flash memory 31 also stores the master key 12a. The same firmware is stored in the flash memory 31 in each of the plurality of writing units 30 .

The socket 32 is a place where the chip 15 is arranged, and has a plurality of recesses corresponding to the terminals (pins) of the chip 15 . The chip 15 placed in the socket 32 is electrically connected to each of the flash memory 31 and the light emitter 33 .

The light emitting unit 33 is, for example, a light emitting element such as an LED (Light Emitting Diode), and notifies the operator of the writing state of the master key 12a in a light emitting manner. The light emission mode may be, for example, different emission colors, presence/absence of light emission, light emission intervals, and the like.

The power supply unit 40 supplies power for operating the chip 15, the light emitting unit 33, and the like.

FIG. 8 is a table showing a control procedure for writing the master key 12a to the chip 15 according to this embodiment. FIG. 8 shows an example of details of step S33 shown in FIG. The processing shown in FIG. 8 is executed by executing the write firmware stored in the flash memory 31 on the chip 15 arranged in the socket 32 of the socket jig 20 . It can be said that FIG. 8 shows the contents of the firmware for writing. In addition, No. shown in FIG. indicates the processing order. Also, the contents shown in FIG. 8 are excerpted contents, and other processes may be included.

As shown in FIG. 8, the chip 15 first activates a real-time OS (Operating System). At this time, for example, "Secure Boot" may be OFF.

Next, the chip 15 energizes the first GPIO (General-Purpose Input/Output). The first GPIO is a pin (terminal) connected to the light emitting unit 33 . As a result, the light-emitting unit 33 (for example, an LED) can be caused to emit light in a light-emitting mode indicating the start of processing, so that the operator can be notified of the start of the write processing of the master key 12a.

Next, the chip 15 writes the master key 12a. Specifically, the master key 12a is written into a secure storage area 12 (eg, secure eFuse) within the chip 15 . By executing the write firmware on the chip 15 in this way, the master key 12 a is automatically written to the secure storage area 12 in the chip 15 .

Next, the chip 15 confirms the written master key 12a. That is, the chip 15 determines whether the written master key 12a is a correct master key. The chip 15, for example, confirms whether the master key 12a written in the secure storage area 12 and the master key 12a to be written (for example, the master key stored in the flash memory 31) match. By doing so, the determination is made.

Next, if the written master key 12a is correct (if it matches the master key 12a to be written), the chip 15 locks the master key 12a. Chip 15 turns on the locking function of the eFuse. The chip 15, for example, turns on "Secure Boot". This prohibits reading the master key 12a from the non-secure zone.

Thus, in the first step, a lock function that prohibits reading of the master key 12a during processing in the non-secure zone may be turned on.

Next, the chip 15 energizes the second GPIO. The second GPIO is a pin (terminal) connected to the light emitting unit 33 and is a different pin from the first GPIO. As a result, the light emitting unit 33 (e.g., LED) can be caused to emit light in a light emission mode indicating that the writing process has been completed normally, so that the operator can be notified that the writing process of the master key 12a has been performed normally. can be notified.

Next, the chip 15 de-energizes the first GPIO. As a result, the chip 15 can turn off the light emitting section 33 (for example, an LED) upon completion of the writing process of the master key 12a.

According to the above control procedure, the master key 12a can be written to the chip 15 in the state of the chip 15 alone. Then, the chip 15 in which the master key 12a is written is transported from the dedicated security room to the production line of the security module 10. FIG.

Referring back to FIG. 6, next, in the method for manufacturing the security module 10, firmware (firmware for the device) corresponding to the device (for example, home appliance) is written into the flash memory 14 (S34). At this time, write firmware for writing the individual values 13 a stored in the flash memory 14 to the non-secure storage area 13 of the chip 15 may also be written in the flash memory 14 . For example, in step S34, in the state of the flash memory 14 alone, that is, in the state where the flash memory 14 is not mounted on the substrate, the individual value 13a is written to the storage area of the chip 15 (for example, the non-secure storage area 13). Firmware may be written to the flash memory 14 . Step S34 is an example of the fourth step.

Then, when the power is supplied for the first time, the firmware for writing out of the firmware for the device and the firmware for writing is set to be executed.

A writing device called a Gang Writer, for example, is used to write the firmware to the flash memory 14, but it is not limited to this.

Next, in the method for manufacturing the security module 10, the encrypted individual key 14a and the individual value 13a are written into the flash memory 14 (S35). Step S35 is performed, for example, in the state of the flash memory 14 alone. Writing in step S35 also uses, for example, a gang writer or the like, but is not limited to this.

Step S35 is an example of the second step. The second step can also be said to be a step of writing the encrypted individual key 14a and the individual value 13a into the flash memory 14 mounted on the substrate together with the chip 15 and capable of being written multiple times. Note that at least the encrypted individual key 14a is written to the flash memory 14 in step S35.

Next, in the method of manufacturing the security module 10, the chip 15 and flash memory 14 are incorporated into the module (S36). For example, chip 15 and flash memory 14 are mounted on the substrate. Note that other components such as an antenna are also mounted on the substrate.

In step S36, the flash memory 14 in which at least the encrypted individual key 14a is written is mounted on the board. In this embodiment, a flash memory 14 in which an encrypted individual key 14a and an individual value 13a are written is mounted on a substrate.

Next, power is supplied to the chip 15 incorporated in the module to execute the write firmware stored in the flash memory 14 . By executing the firmware, the individual value 13a stored in the flash memory 14 is written to the non-secure storage area 13 of the chip 15 (S37). Thus, the individual value 13a is obtained from a storage device outside the chip 15, such as the flash memory 14 or the like. Step S37 is an example of the third step. The third step can also be said to be a step of writing the individual value 13a written in the flash memory 14 to the storage area of the chip 15 (for example, the non-secure storage area 13).

Note that the individual value 13a is not limited to being written to the non-secure storage area 13 via the flash memory 14, and may be written via another storage device. For example, the individual value 13a may be stored in a RAM (Random Access Memory) or the like on the module via a serial port, and written to the non-secure storage area 13 via the RAM.

After the individual value 13a is written to the non-secure storage area 13 of the chip 15, the individual value 13a written to the flash memory 14 may be deleted. That is, the method of manufacturing the security module 10 may further include a step of deleting the individual value 13a written in the flash memory 14 (an example of the fifth step).

As described above, in the method of manufacturing the security module 10 according to the present embodiment, the master key 12a is written in the secure storage area 12 (an example of a storage area within the secure zone), and the encrypted individual key 14a is , is written to the flash memory 14 (an example of a storage area in the non-secure zone).

The manufacturing method of the security module 10 is not limited to the manufacturing method shown in FIG. Another example of the method of manufacturing the security module 10 will be described with reference to FIG. FIG. 9 is a flow chart showing another example of the method for manufacturing the security module 10 according to this embodiment. The flowchart shown in FIG. 9 differs from the flowchart shown in FIG. 6 in that the order of steps S35 and S36 is changed. The following description focuses on the differences from FIG.

As shown in FIG. 9, in the method of manufacturing the security module 10, after writing firmware corresponding to the device into the flash memory 14 (S34), the chip 15 and the flash memory 14 are incorporated into the module (S36). That is, the flash memory 14 is incorporated into the module in a state in which only the firmware out of the firmware and the encrypted individual key 14a and the individual value 13a is written. It can also be said that the flash memory 14 is incorporated into a module in a state in which information written in common to other flash memories 14 is written.

At this time, write firmware for writing the individual value 13 a stored in the flash memory 14 to the non-secure storage area 13 of the chip 15 is also written to the flash memory 14 .

Next, in the method of manufacturing the security module 10, the encrypted individual key 14a and the individual value 13a are written into the flash memory 14 incorporated in the module (S35). Writing the encrypted individual key 14a and the individual value 13a to the flash memory 14 is performed using, for example, a PC (Personal Computer). For example, the encrypted individual key 14a and the individual value 13a are written into the flash memory 14 by connecting the PC and the flash memory 14 via a dedicated connector or the like.

Step S35 is an example of the second step. The second step may be performed with the flash memory 14 mounted on the substrate.

Next, as in FIG. 6, the firmware is executed to write the individual value 13a stored in the flash memory 14 to the non-secure storage area 13 of the chip 15 (S37).

Such a method for manufacturing the security module 10 is effective, for example, when the gang writer does not have the function of writing mutually different information (for example, mutually different individual values 13a) into each of the plurality of flash memories 14. .

(Other embodiments)
Although the method for manufacturing a security module according to one or more aspects has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as it does not deviate from the spirit of the present disclosure, the present disclosure may include various modifications that a person skilled in the art can come up with, and a configuration constructed by combining the components of different embodiments. .

For example, in the security module manufacturing method in the above embodiment, each step may be performed by an operator, or a part thereof may be performed automatically.

In addition, in the above embodiments and the like, each component may be configured with dedicated hardware or implemented by executing a software program suitable for each component. Each component may be realized by reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory by a program execution unit such as a CPU or processor.

Also, the division of functional blocks in the block diagram is an example, and a plurality of functional blocks can be realized as one functional block, one functional block can be divided into a plurality of functional blocks, and some functions can be moved to other functional blocks. may Moreover, single hardware or software may process the functions of a plurality of functional blocks having similar functions in parallel or in a time-sharing manner.

Also, each component described in the above embodiments and the like may be realized as software, or typically as an LSI, which is an integrated circuit. These may be made into one chip individually, or may be made into one chip so as to include part or all of them. Although LSI is used here, it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. Also, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections or settings of the circuit cells inside the LSI may be used. Furthermore, if an integrated circuit technology that replaces the LSI appears due to advances in semiconductor technology or another technology derived from it, the component may naturally be integrated using that technology.

A system LSI is a multi-functional LSI manufactured by integrating multiple processing units on a single chip. Specifically, it includes a microprocessor, ROM (Read Only Memory), RAM, etc. It is a computer system that A computer program is stored in the ROM. The system LSI achieves its functions by the microprocessor operating according to the computer program.

Also, one aspect of the present disclosure may be a computer program that causes a computer to execute at least one of the characteristic steps included in the security module manufacturing method shown in FIG. 6, FIG. 8, or FIG.

Also, for example, the program may be a program to be executed by a computer. Also, one aspect of the present disclosure may be a computer-readable non-transitory recording medium on which such a program is recorded. For example, such a program may be recorded on a recording medium and distributed or distributed. For example, by installing the distributed program in a device having another processor and causing the processor to execute the program, it is possible to cause the device to perform the above processes.

Also, the order of each step in the security module manufacturing method described in the above embodiments may be changed. Further, each step in the security module manufacturing method described in the above embodiment may be performed in one step or in separate steps. It should be noted that "performed in one step" means that each step is performed using one device, each step is performed continuously, or each step is performed at the same place. is. In addition, separate steps mean that each step is performed using separate equipment, each step is performed at different times (for example, different days), or each step is performed at different locations. intended to include

In addition, these general or specific aspects may be realized by a system, method, integrated circuit, computer program, or non-transitory recording medium such as a computer-readable CD-ROM. It may be realized by any combination of circuits, computer programs or recording media. The program may be pre-stored in a recording medium, or may be supplied to the recording medium via a wide area network including the Internet.

The present disclosure is useful for manufacturing security modules.

1 IoT Home Appliance 2 Internet 3 Cloud System 10 Security Module 11 Control Unit 12 Secure Storage Area 12a Master Key 13 Non-Secure Storage Area

13a Individual Value

14, 31 Flash Memory 14a Encryption Individual Key 15 Chip (IC)
20 socket jig 30 writing unit 32 socket 33 light emitting unit 40 power supply unit

Claims

A manufacturing method for manufacturing a security module holding a master key and an encrypted individual key obtained by encrypting the individual key with the master key,
a first step of writing the master key in a single writable storage area in an IC (Integrated Circuit) mounted on the security module;
and a second step of writing the encrypted individual key into a memory mounted on a board together with the IC and capable of being written multiple times.
The second step is performed on a production line that manufactures the security module,
2. The method of manufacturing a security module according to claim 1, wherein said first step is performed in a dedicated security room isolated from said manufacturing line.
The second step is performed in the state of the memory alone,
3. The method of manufacturing a security module according to claim 1, wherein the memory in which the individual encryption key is written is mounted on the board.
3. The method of manufacturing a security module according to claim 1, wherein the second step is performed with the memory mounted on the substrate.
The encrypted individual key is further encrypted using an individual value unique to the security module,
In the second step, further writing the individual value to the memory;
5. The method of manufacturing a security module according to any one of claims 1 to 4, further comprising a third step of writing said individual value written in said memory into said memory area of said IC.
6. The method of manufacturing a security module according to claim 5, further comprising a fourth step of writing firmware into said memory for writing said individual value into said storage area of said IC.
The fourth step is performed in the state of the memory alone,
7. The method of manufacturing a security module according to claim 6, wherein the memory in which the encrypted individual key and the individual value are written is mounted on the board.
8. The method of manufacturing a security module according to any one of claims 5 to 7, further comprising a fifth step of deleting said individual value written in said memory after said third step.
The IC has a secure zone and a non-secure zone,
the master key is written to a storage area within the secure zone;
The security module manufacturing method according to any one of claims 1 to 8, wherein the encrypted individual key is written in a storage area within the non-secure zone.
10. The method of manufacturing a security module according to claim 9, wherein in the first step, a lock function that prohibits reading of the master key is turned on during processing in the non-secure zone.