JP7019976B2 - Secure element, computer program, device, OS boot system and OS boot method - Google Patents

Description

The present invention relates to a secure element, a computer program, a device, an OS boot system, and an OS boot method.

Most of the security of electronic devices including personal computers is guaranteed by the OS running on the devices. Therefore, in general, an attacker attacks a vulnerability in the OS or replaces the OS with a vulnerable one.

Therefore, a technique for ensuring security by detecting an unauthorized attack such as falsification or replacement of an OS at the time of starting the OS is being researched. For example, in Patent Document 1, when a trusted device is connected to a terminal, a connection is made between the terminal and the OS server based on the boot loader taken out from the trusted device, and the OS server is encrypted to the terminal. A method of downloading a boot image (OS kernel) and decrypting the downloaded boot image with a key obtained from a trusted device is disclosed.

Japanese Patent No. 5940159

However, in the method of Patent Document 1, the OS image is obtained by intercepting the communication when the decryption key is taken out from the trusted device, and the server for obtaining the OS image is changed to the attacker's server. It can be tampered with or replaced.

On the other hand, IoT (Internet of Things) creates new added value by connecting a wide variety of devices to the network. In such a device, the boot mechanism is different for each device, so a separate boot loader is required for each device. However, in the method of Patent Document 1, since the terminal boots the OS based on the boot loader included in the trusted device, it is not possible to boot the OS of a wide variety of devices.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a secure element, a computer program, a device, an OS boot system, and an OS boot method that can ensure security at the time of OS boot of a device. And.

The secure element according to the embodiment of the present invention includes a request signal acquisition unit that acquires an OS request signal from a boot loader for reading the OS, and an encrypted OS when the request signal acquisition unit acquires the request signal. It includes a decoding unit that decodes an image, and an output unit that outputs an OS image decoded by the decoding unit for reading by the boot loader.

The computer program according to the embodiment of the present invention is a computer program for causing a computer to output an OS image to be read by a boot loader, and is a process of acquiring an OS request signal from the boot loader and the request. When the signal is acquired, the process of decoding the encrypted OS image and the process of outputting the decrypted OS image for reading by the boot loader are executed.

The device according to the embodiment of the present invention includes a secure element according to the embodiment of the present invention and a boot loader for reading an OS.

The OS boot system according to the embodiment of the present invention includes the device according to the embodiment of the present invention and a server that encrypts and stores the image of the OS read by the boot loader.

In the OS boot method according to the embodiment of the present invention, the request signal acquisition unit acquires the request signal of the OS from the boot loader for reading the OS, and when the request signal is acquired, the encrypted OS image is decoded. Since the unit decodes and reads it by the boot loader, the output unit outputs the decoded OS image.

According to the present invention, security at the time of booting the OS of the device can be ensured.

It is a block diagram which shows an example of the structure of the OS boot system of this embodiment. It is explanatory drawing which shows an example of the operation at the time of online booting of the OS boot system of this embodiment. It is explanatory drawing which shows an example of the operation at the time of offline booting of the OS boot system of this embodiment. It is a flowchart which shows an example of the OS boot processing procedure by the secure element of this embodiment. It is explanatory drawing which shows an example of the operation at the time of OS image collation of the OS boot system of this embodiment. It is a flowchart which shows an example of the OS image collation processing procedure by the secure element of this embodiment.

Hereinafter, the present invention will be described with reference to the drawings showing the embodiments thereof. FIG. 1 is a block diagram showing an example of the configuration of the OS boot system of the present embodiment. The OS boot system of the present embodiment includes a device 100 in which the secure element 50 is incorporated, a server 200, and the like. The device 100 is a device (also referred to as an electronic device) capable of independently operating by mounting an OS, and includes a device corresponding to "things" in the "Internet of Things" (IoT).

In addition to the secure element 50, the device 100 includes a CPU 10, a network communication unit 11, a non-volatile recording unit 12 such as a ROM or a non-volatile memory, a RAM 13, a power switch 14 for turning on / off the power, a BIOS 21, and a boot loader 22. It is equipped with an OS kernel 23, a file system 24, and the like. For convenience, the portion of the device 100 other than the secure element 50 is referred to as the device side.

The non-volatile recording unit 12 is written with the contents recorded at the time of manufacturing the device 100, but can be rewritten during the operation of the device 100.

The RAM 13 is a volatile memory, and the recorded contents are erased when the power is turned off and on again by the power switch 14.

The BIOS 21 is a software component (software module) held in the non-volatile recording unit 12 and for controlling the basic input / output of the device 100.

The boot loader 22 is a software component held in the non-volatile recording unit 12 and called from the BIOS 21 to be started. The boot loader 22 operates to read the OS kernel into the RAM 13.

The OS kernel 23 is a software component that implements the basic functions of the OS. The OS kernel 23 is expanded on the RAM 13 by the boot loader 22 and executed by the CPU 10 to provide the functions of the OS to the application or the user. In this embodiment, the OS kernel 23 is included in the OS image. The OS image is a collection of a plurality of files and folders constituting the OS into one file.

The file system 24 is a set of data that holds all the file (folder) trees handled on the device 100. By recognizing the file system 24 by the OS kernel 23, the application or the user can read and write the files in the file system 24. The file system 24 is included in the OS image.

The network communication unit 11 has a function of connecting the device 100 to the network, and can send and receive information to and from other devices or clouds (servers) on the network. The network communication unit 11 can transmit information detected by sensors (not shown).

The secure element 50 is special hardware that is composed of a semiconductor element such as an IC chip or an IC card and has tamper resistance against physical and logical attacks from the outside.

The secure element 50 includes a download processing unit 51, a decryption processing unit 52, a comparison processing unit 53, a non-volatile memory 54 as a storage unit, an offline start permission flag 55, an encrypted OS image 56, an OS image decryption key 57, and the like. For convenience, the encrypted OS image 56 is also referred to as an OS image 56.

The non-volatile memory 54 can be, for example, a non-volatile memory having tamper resistance.

The download processing unit 51 has a function as a communication unit, establishes a secret communication path 61 for the server 200, and downloads the encrypted OS image of the server 200 to the non-volatile memory 54. As a result, the OS image can be safely acquired while maintaining confidentiality. In the secret communication path 61, communication can be performed by a protocol such as TLS (Transport Layer Security), for example. The protocol is not limited to TLS.

The decryption processing unit 52 has a function as a decryption unit, decrypts and decrypts the OS image 56 held in the non-volatile memory 54, and deciphers the decrypted OS image on the RAM 13 of the device 100. expand. By performing the decryption process of the encrypted OS image 56 in the secure element 50, it is possible to prevent falsification or replacement of the OS image.

The comparison processing unit 53 has a function as a collation unit, and in response to a request from the device 100, the OS image of the OS running on the device 100 and the OS image 56 held in the non-volatile memory 54 are combined. Compare and collate (determine match / mismatch). The collation of the OS image may be the whole OS image or a part (for example, a part of the OS kernel, a part of the file system). The collation algorithm may be, for example, plaintext collation, but is not limited to this.

The encrypted OS image 56 is data in which the OS kernel 561 and the file system 562 are put together and encrypted with the OS image encryption key.

The OS image decryption key 57 is held in the non-volatile memory 54. As a result, the confidentiality of the OS image decryption key 57 can be ensured. The OS image decryption key 57 is a key for decrypting the encrypted OS image 56 and taking out the OS kernel 23 and the file system 24. The OS image decryption key 57 may be a fixed key or a key that is dynamically updated.

The offline activation permission flag 55 has a function as an identifier. The offline boot permission flag 55 allows or rejects booting only with the OS image 56 held in the non-volatile memory 54 of the secure element 50 when the OS of the device 100 is booted (offline booting). It is a flag to judge. If rejected, the download processing unit 51 downloads the latest OS image from the server 200. By having the secure element 50, not the device side, an identifier that determines the source of the OS read by the boot loader 22 on the device side (for example, the URL of the server from which the OS is obtained), the secure element 50 acquires the OS image. You can decide the destination.

The secure element 50 is connected to the device side via the internal buses 31 and 32. More specifically, the internal bus 31 connects the secure element 50 and the non-volatile recording unit 12, and the internal bus 32 connects the secure element 50 and the RAM 13. As the internal buses 31 and 32, any appropriate bus can be used as long as it can ensure confidentiality.

The server 200 holds the encrypted image 201 (including the OS kernel 202 and the file system 203), and distributes the encrypted image 201 to the secure element 50 via the secret communication path 61 when the OS of the device 100 is started.

Next, the operation of the OS boot system of this embodiment will be described. In the following, the operation at the time of online startup, the operation at the time of offline startup, and the operation at the time of collating the OS image will be described.

FIG. 2 is an explanatory diagram showing an example of the operation of the OS boot system of the present embodiment at the time of online booting. Hereinafter, the processes represented by the reference numerals P1 to P13 will be described.

P1 (power on): The user operates the power switch 14 to turn on the power to the device 100.

P2 (Startup of BIOS21): The power-on device 100 activates the BIOS21 held in the non-volatile recording unit 12.

P3 (Startup of boot loader 22): BIOS 21 starts the boot loader 22 held in the non-volatile recording unit 12.

P4 (OS image download request): The boot loader 22 makes an OS image download request (also referred to as an OS request signal) to the secure element 50. The secure element 50 has a function as a request signal acquisition unit, and when the request is acquired, the secure element 50 calls a process by the download processing unit 51.

P5 (offline start check): The download processing unit 51 checks the offline start permission flag 55 held in the non-volatile memory 54, and confirms that the flag is “rejected (online start)”.

P6 (Establishment of secret communication path 61): When the download processing unit 51 confirms that the flag is "rejection", the download processing unit 51 establishes an end-to-end secret communication path 61 for the server 200. The secret communication path 61 can be, for example, TLS (HTTPS). If the secure element 50 has its own physical communication means (for example, LAN or WiFi), the communication path can be established by itself, but if it does not have the communication means, the physical communication of the device 100 can be performed. Means may be used.

P7 (Download OS image): The secure element 50 requests the server 200 to download the OS image. The download processing unit 51 downloads the encrypted OS image 201 from the server 200 to the secure non-volatile memory 54 and holds it.

P8 (Change of offline start permission flag 55): When the server 200 wants to change the offline start permission flag 55, the server 200 changes the offline start permission flag 55 for the secure element 50 via the secret communication path 61. The secure element 50 has a function as a reception unit, and accepts a process of setting the offline activation permission flag 55 to "deny (online activation)" or "permission (offline activation)" via a secret communication path. This makes it possible to change the acquisition destination of the OS image according to the situation. The offline activation permission flag 55 can be changed not only at the time of online activation but also at any timing.

P9 (Download complete): The download processing unit 51 notifies the boot loader 22 that the download is complete.

P10 (OS image expansion request): Upon receiving the notification of download completion, the boot loader 22 requests the secure element 50 to expand the OS image. When the secure element 50 receives a request for expanding the OS image, the secure element 50 calls a process by the decryption processing unit 52.

P11 (decoding and decompression of OS image): The decryption processing unit 52 decodes the encrypted OS image 56 held in the non-volatile memory 54 by using the OS image decryption key 57. By performing the decryption processing of the encrypted OS image 56 stored in the highly secure non-volatile memory 54 in the secure element 50, it is possible to prevent the OS image from being tampered with or replaced. The decryption processing unit 52 has a function as an output unit, outputs the decoded OS kernel 23 and the file system 24 to the device side, and deploys them on the RAM 13. Since the device side and the secure element 50 can be connected by an internal bus 32 having confidentiality, it is possible to prevent falsification or replacement of the booted OS image.

P12 (booting the OS kernel 23): The boot loader 22 boots the OS kernel 23 expanded on the RAM 13.

P13 (reading of file system 24): The OS kernel 23 enables and makes the file system 24 expanded on the RAM 13 accessible. After the file system 24 is activated, the OS completes booting and transitions to steady state. This makes it possible to provide the user with OS functions such as permitting the user to log in and starting the server service.

As described above, since the boot loader 22 is located on the device side separately from the secure element 50, the secure element 50 can have a common structure for a wide variety of devices 100. Further, with the above configuration, it is possible to secure the security at the time of OS booting of a wide variety of devices 100.

FIG. 3 is an explanatory diagram showing an example of the operation of the OS boot system of the present embodiment at the time of offline booting. Hereinafter, the processes represented by the reference numerals P21 to P30 will be described. At the time of offline startup, the encrypted OS image 201 is not downloaded from the server 200.

P21 (power on): The user operates the power switch 14 to turn on the power to the device 100.

P22 (Startup of BIOS21): The power-on device 100 activates the BIOS21 held in the non-volatile recording unit 12.

P23 (Starting the boot loader 22): The BIOS 21 starts the boot loader 22 held in the non-volatile recording unit 12.

P24 (OS image download request): The boot loader 22 makes an OS image download request (also referred to as an OS request signal) to the secure element 50. When the secure element 50 acquires the request, the secure element 50 calls the process by the download processing unit 51.

P25 (offline start check): The download processing unit 51 checks the offline start permission flag 55 held in the non-volatile memory 54, and confirms that the flag is “permitted (offline start)”.

P26 (confirmation of existence of OS image): When the download processing unit 51 confirms that the flag is "permitted", it confirms whether the encrypted OS image 56 is held in the non-volatile memory 54, and the encrypted OS image 56. Is retained, the boot loader 22 is notified that the download is complete.

P27 (OS image expansion request): Upon receiving the notification of download completion, the boot loader 22 requests the secure element 50 to expand the OS image. When the secure element 50 receives a request for expanding the OS image, the secure element 50 calls a process by the decryption processing unit 52.

P28 (decoding and decompression of OS image): The decryption processing unit 52 decodes the encrypted OS image 56 held in the non-volatile memory 54 by using the OS image decryption key 57. By performing the decryption processing of the encrypted OS image 56 stored in the highly secure non-volatile memory 54 in the secure element 50, it is possible to prevent the OS image from being tampered with or replaced. The decryption processing unit 52 outputs the decrypted OS kernel 23 and the file system 24 to the device side, and deploys them on the RAM 13. Since the device side and the secure element 50 can be connected by an internal bus 32 having confidentiality, it is possible to prevent falsification or replacement of the booted OS image.

P29 (booting the OS kernel 23): The boot loader 22 boots the OS kernel 23 expanded on the RAM 13.

P30 (reading of file system 24): The OS kernel 23 enables and makes the file system 24 expanded on the RAM 13 accessible. After the file system 24 is activated, the OS completes booting and transitions to steady state. This makes it possible to provide the user with OS functions such as permitting the user to log in and starting the server service.

With the above configuration, it is possible to ensure the security at the time of OS booting of a wide variety of devices 100.

FIG. 4 is a flowchart showing an example of the OS boot processing procedure by the secure element 50 of the present embodiment. The secure element 50 acquires an OS image download request from the boot loader 22 (S11). The secure element 50 determines the offline start permission flag 55 (S12), and if it is rejected (rejected in S12), establishes a secret communication path 61 with the server 200 (S13).

The secure element 50 downloads an encrypted OS image (encrypted OS image 201) from the server 200 via the secret communication path 61 (S14), and notifies the boot loader 22 of the completion of the download (S15).

The secure element 50 determines whether or not there is an OS image request from the boot loader 22 (S16), and if there is no request (NO in S16), the process of step S16 is continued. When requested (YES in S16), the secure element 50 decodes the encrypted OS image (S17), expands the decrypted OS image on the RAM 13 of the device 100 (S18), and ends the process. ..

When the offline start permission flag 55 is permitted (permitted in S12), the secure element 50 determines whether or not the encrypted OS image (encrypted OS image 56) is stored (retained) in the non-volatile memory 54. If it is determined (S19) and stored (YES in S19), the processing after step S15 is performed.

If the encrypted OS image is not stored (NO in S19), the secure element 50 ends the process. When the encrypted OS image is not stored, the processing of the secure element 50 can comply with the operational security policy, and as described above, the operation may be stopped, or the operation may be stopped. The encrypted OS image 201 may be forcibly downloaded from the server 200.

FIG. 5 is an explanatory diagram showing an example of the operation of the OS boot system of the present embodiment at the time of OS image matching. Hereinafter, the processes represented by the reference numerals P41 to P45 will be described.

P41 (input of OS kernel 23): The device 100 outputs the contents of the currently operating OS kernel 23 to the secure element 50. The secure element 50 holds the acquired contents of the OS kernel 23 on the RAM 58.

P42 (input of file system 24): The device 100 outputs the contents of the current file system 24 to the secure element 50. The secure element 50 holds the acquired contents of the file system 24 on the RAM 58.

P43 (Expansion of data to be collated): The decryption processing unit 52 decodes the encrypted OS image 56 held in the non-volatile memory 54, and puts the decrypted OS kernel 563 and the file system 564 (both in plain text) on the RAM 58. expand.

P44 (collation): The comparison processing unit 53 collates the OS kernel 23 expanded on the RAM 58 with the OS kernel 563, and makes a match / mismatch determination. Further, the comparison processing unit 53 collates the file system 24 expanded on the RAM 58 with the file system 564, and makes a match / mismatch determination. The collation of the OS image may be the whole OS image or a part (for example, a part of the OS kernel, a part of the file system). The collation algorithm may be, for example, plaintext collation, but is not limited to this.

P45 (Notification of collation result): The comparison processing unit 53 has a function as a notification unit, and notifies the collation result (for example, match or mismatch) to the OS 23 read by the boot loader 22. Since it can be compared with the correct OS image stored in the non-volatile memory 54, it is possible to confirm whether the OS operating on the device side is correct (for example, whether it has been tampered with).

The secure element 50 has a function as a stop unit, and stops the operation of the OS read by the boot loader 22 based on the collation result in the comparison processing unit 53. For example, if it is determined that the OS images do not match, the operation of the OS on the device side can be stopped to prevent adverse effects due to incorrect OS operation. The device may be provided with the function of the stop unit. In this case, for example, the CPU 10 can execute the function of the stop unit. That is, the secure element 50 outputs the collation result in the comparison processing unit 53 to the device side (CPU 10), and the CPU 10 stops the operation of the OS read by the boot loader 22 based on the collation result in the comparison processing unit 53. Let me.

The secure element 50 has a function as a recovery unit, and restores the image of the OS read by the boot loader 22 based on the collation result in the comparison processing unit 53. For example, when it is determined that the OS images do not match, the adverse effect of the incorrect OS operation can be prevented by restoring the OS on the device side to the correct OS. The device may be provided with the function of the recovery unit. In this case, for example, the CPU 10 can execute the function of the recovery unit. That is, the secure element 50 outputs the collation result in the comparison processing unit 53 to the device side (CPU 10), and the CPU 10 recovers the image of the OS read by the boot loader 22 based on the collation result in the comparison processing unit 53. Let me.

The above-mentioned OS image collation process can be executed at an appropriate timing such as every minute, every hour, every day, and the like. Further, the OS image collation process can also be performed by comparing hash values using a hash function.

FIG. 6 is a flowchart showing an example of the OS image collation processing procedure by the secure element 50 of the present embodiment. The secure element 50 acquires the contents of the operating OS kernel 23 from the device side (S31), and acquires the contents of the current file system 24 from the device side (S32). The secure element 50 holds the acquired contents of the OS kernel 23 and the contents of the file system 24 on the RAM 58 (S33).

The secure element 50 reads the encrypted OS image 56 from the storage unit (nonvolatile memory 54) (S34), reads the encrypted OS kernel 561 and the encrypted file system 562, and uses the OS image decryption key 57. Decrypt using (S35).

The secure element 50 expands the decrypted OS kernel 563 and the file system 564 on the RAM 58 (S36). The secure element 50 performs a comparison process (collation process) of the OS image (OS kernel and file system) (S37), notifies the device side (operating OS) of the collation result (S38), and ends the process.

A computer program having a processing procedure as shown in FIGS. 4 and 6 is loaded into a secure non-volatile memory having confidentiality, and the computer program is executed by a CPU (processor) in the secure element 50. The download processing unit 51, the decoding processing unit 52, and the comparison processing unit 53 can be realized.

As described above, according to the present embodiment, since the device 100 is individually provided with the boot loader, individual settings including hardware control can be performed for each device 100. Further, the processing related to the booting of the OS can be made common and minimized by making only the OS image request to the secure element 50 and the booting of the OS image.

Further, according to the present embodiment, the secure element 50 can safely hold the OS image acquired from the server 200 while maintaining confidentiality, and functions as a supply source of the OS image at the time of offline startup. be able to. Further, since the secure element 50 safely holds the OS image, it can be collated with the operating OS image on the device side, and even if the OS image on the device side is damaged or tampered with. It can be restored to the correct OS image.

Further, according to the present embodiment, since the OS image decoding process and the OS image decoding key 57 are held inside the secure element 50, the correct OS image is provided to the device side while maintaining the tamper resistance of both. can do.

Further, according to the present embodiment, by enabling the offline start permission flag 55 to be set from the server 200, the start control of the device 100 can be performed via the network. Further, the secure element 50 can supply the correct OS image to the device side even at the time of offline startup.

The secure element according to the present embodiment has a request signal acquisition unit that acquires an OS request signal from a boot loader for reading the OS, and an encrypted OS image when the request signal acquisition unit acquires the request signal. It includes a decoding unit for decoding and an output unit for outputting an OS image decoded by the decoding unit for reading by the boot loader.

The computer program according to the present embodiment is a computer program for causing a computer to output an OS image to be read by a boot loader, and causes the computer to acquire an OS request signal from the boot loader and to transmit the request signal. When it is acquired, the process of decrypting the encrypted OS image and the process of outputting the decrypted OS image for reading by the boot loader are executed.

The device according to this embodiment includes a secure element according to this embodiment and a boot loader for reading an OS.

The OS boot system according to the present embodiment includes a device according to the present embodiment and a server that encrypts and stores an OS image read by the boot loader.

In the OS boot method according to the present embodiment, the request signal acquisition unit acquires the OS request signal from the boot loader for reading the OS, and when the request signal is acquired, the decryption unit extracts the encrypted OS image. Since it is decoded and read by the boot loader, the output unit outputs the decoded OS image.

The request signal acquisition unit acquires the request signal of the OS from the boot loader for reading the OS. A boot loader is provided on the device that incorporates the secure element. For convenience, the part of the device other than the secure element is referred to as the device side. By having the boot loader on the device side, the secure element can have a common structure for a wide variety of devices.

When the request signal acquisition unit acquires the request signal, the decoding unit decodes the encrypted OS image. By performing the decryption process of the encrypted OS image in the secure element, the decryption process and the confidentiality of the decryption key can be ensured.

Since the output unit is read by the boot loader, the OS image decoded by the decoding unit is output. That is, the output unit outputs the decoded OS image to the device side. Since the device side and the secure element can be connected by an internal bus having confidentiality, it is possible to prevent falsification or replacement of the booted OS image.

With the above configuration, it is possible to ensure the security at the time of OS booting of a wide variety of devices.

The secure element according to the present embodiment includes an identifier for identifying an activation mode and a communication unit for establishing an encrypted secret communication path with a predetermined server, and the communication unit has the identifier online. When it is started, the encrypted OS image is acquired from the server, and the decryption unit decodes the OS image acquired by the communication unit.

The identifier identifies the activation mode. The activation mode can be, for example, online activation and offline activation. Since the secure element has an identifier that determines the acquisition destination of the OS read by the boot loader on the device side instead of the device side, the acquisition destination of the OS image can be determined by the secure element.

The communication unit establishes an encrypted secret communication path with a predetermined server. In the secret communication path, communication can be performed by a protocol such as TLS (Transport Layer Security), for example.

When the identifier is online startup, the communication unit acquires the encrypted OS image from the server. As a result, the OS image can be safely acquired while maintaining confidentiality.

The decoding unit decodes the OS image acquired by the communication unit. By performing the decryption process of the safely acquired OS image in the secure element, it is possible to prevent the OS image from being tampered with or replaced.

The secure element according to the present embodiment includes a storage unit for storing an encrypted OS image, and the decoding unit decodes the OS image stored in the storage unit when the identifier is offline activation.

The storage unit stores the encrypted OS image. The storage unit can be, for example, a non-volatile memory having tamper resistance.

When the identifier is offline activation, the decoding unit decodes the OS image stored in the storage unit. By performing the decryption process of the OS image stored in the highly secure storage unit in the secure element, it is possible to prevent falsification or replacement of the OS image.

The secure element according to the present embodiment includes an acquisition unit that acquires an image of the OS read by the boot loader, and a collation unit that collates the OS image acquired by the acquisition unit with the OS image stored in the storage unit. It is provided with a notification unit for notifying the OS read by the boot loader of the collation result in the collation unit.

The acquisition unit acquires the image of the OS read by the boot loader. For example, it is possible to acquire an operating OS image on the device side.

The collation unit collates the OS image acquired by the acquisition unit with the OS image stored in the storage unit. The collation of the OS image may be the whole OS image or a part (for example, a part of the OS kernel, a part of the file system). The collation algorithm may be, for example, plaintext collation, but is not limited to this.

The notification unit notifies the OS read by the boot loader of the collation result (for example, match or mismatch) in the collation unit. Since it can be compared with the correct OS image stored in the storage unit, it is possible to confirm whether the OS running on the device side is correct (for example, whether it has been tampered with).

The secure element according to the present embodiment includes a stop unit for stopping the operation of the OS read by the boot loader based on the collation result in the collation unit.

The device according to the present embodiment includes a stop unit for stopping the operation of the OS read by the boot loader based on the collation result of the secure element in the collation unit.

The stop unit stops the operation of the OS read by the boot loader based on the collation result in the collation unit. For example, if it is determined that the OS images do not match, the operation of the OS on the device side can be stopped to prevent adverse effects due to incorrect OS operation.

The secure element according to the present embodiment includes a recovery unit that recovers the image of the OS read by the boot loader based on the collation result in the collation unit.

The device according to the present embodiment includes a recovery unit that recovers the image of the OS read by the boot loader based on the collation result of the secure element in the collation unit.

The recovery unit recovers the OS image read by the boot loader based on the collation result in the collation unit. For example, when it is determined that the OS images do not match, the adverse effect of the incorrect OS operation can be prevented by restoring the OS on the device side to the correct OS.

The secure element according to the present embodiment includes a reception unit that accepts a process of setting the identifier to online activation or offline activation via the secret communication path.

The reception unit accepts the process of setting the identifier to online activation or offline activation via the secret communication channel. For example, the identifier can be set from the server. This makes it possible to change the acquisition destination of the OS image according to the situation.

10 CPU
11 Network communication unit 12 Non-volatile recording unit 13 RAM
14 Power switch 21 BIOS
22 Boot loader 23 OS kernel 24 File system 31, 32 Internal bus 50 Secure element 51 Download processing unit 52 Decoding processing unit 53 Comparison processing unit 54 Non-volatile memory 55 Offline boot permission flag 56 Encrypted OS image 561 OS kernel 562 File system 57 OS Image decryption key 58 RAM
61 Secret communication path 200 Server 201 Encrypted OS image 202 OS kernel 203 File system

Claims (12)

A request signal acquisition unit that acquires the OS request signal from the boot loader for reading the OS,
A storage unit that stores the encrypted OS image,
When the request signal is acquired by the request signal acquisition unit, a decoding unit that decodes the encrypted OS image stored in the storage unit and a decoding unit.
An output unit that outputs an OS image decoded by the decoding unit for reading by the boot loader, and an output unit .
An identifier that identifies the activation mode and
With a communication unit that establishes an encrypted secret communication path with a predetermined server
Equipped with
The communication unit
If the identifier is online boot, get the encrypted OS image from the server and
The encrypted OS image acquired by the communication unit is stored in the storage unit, and the encrypted OS image is stored in the storage unit.
The decoding unit
A secure element that decrypts the encrypted OS image stored in the storage unit . Equipped with a storage unit that stores the encrypted OS image,
The decoding unit
The secure element according to claim 1 , wherein when the identifier is started offline, the OS image stored in the storage unit is decoded. The acquisition unit that acquires the image of the OS read by the boot loader,
A collation unit that collates the OS image acquired by the acquisition unit with the OS image stored in the storage unit, and
The secure element according to claim 2 , further comprising a notification unit that notifies the OS read by the boot loader of the collation result in the collation unit. The secure element according to claim 3 , further comprising a stop unit for stopping the operation of the OS read by the boot loader based on the collation result in the collation unit. The secure element according to claim 3 , further comprising a recovery unit that recovers an image of an OS read by the boot loader based on a collation result in the collation unit. The secure element according to any one of claims 1 to 5 , further comprising a reception unit that accepts a process of setting the identifier to online activation or offline activation via the secret communication path. A computer program for outputting an OS image to a secure element for reading by the boot loader.
On the computer
The process of acquiring the OS request signal from the boot loader and
The process of storing the encrypted OS image in the storage unit of the secure element , and
When the request signal is acquired, the process of decrypting the encrypted OS image stored in the storage unit and
The process of outputting the decrypted OS image for reading by the boot loader ,
The process of establishing an encrypted secret communication path with a predetermined server,
When the identifier that identifies the boot mode is online boot, the process of acquiring the encrypted OS image from the server and
The process of storing the acquired encrypted OS image in the storage unit,
The process of decrypting the encrypted OS image stored in the storage unit
A computer program that runs a computer program. A device comprising the secure element according to any one of claims 1 to 6 and a boot loader for reading an OS. Claimed to include a stop unit for stopping the operation of the OS read by the boot loader based on a collation result of collating the image of the OS read by the boot loader with the OS image stored in the storage unit of the secure element. 8. The device according to 8. A claim comprising a recovery unit for recovering an OS image read by the boot loader based on a collation result of collating the OS image read by the boot loader with the OS image stored in the storage unit of the secure element. 8. The device according to 8. An OS boot system comprising the device according to any one of claims 8 to 10 and a server that encrypts and stores an OS image read by the boot loader. The request signal acquisition unit acquires the OS request signal from the boot loader for reading the OS.
The encrypted OS image is stored in the storage part of the secure element , and it is stored.
When the request signal is acquired, the decoding unit decodes the encrypted OS image stored in the storage unit, and the decryption unit decodes the encrypted OS image.
Since it is read by the boot loader, the output unit outputs the decrypted OS image.
The communication unit establishes an encrypted secret communication path with a predetermined server, and
When the identifier that identifies the boot mode is online boot, the communication unit acquires the encrypted OS image from the server.
The acquired encrypted OS image is stored in the storage unit, and the image is stored in the storage unit.
The decryption unit decodes the encrypted OS image stored in the storage unit .
OS boot method using secure element .

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