KR20210060798A - Guaranteeing integrity system and method of embedded software based on Cipher-Block Chaining - Google Patents

Abstract

The present invention relates to a CBC-based embedded software integrity guarantee system and method thereof, and more particularly, to a CBC (Cipher-Block Chaining)-based embedded software integrity for secure booting of embedded software. In the guarantee system, an encryption unit 100 for generating secure boot image data by applying a predetermined encryption algorithm to input image data, and the secure boot image data generated by the encryption unit 100 In the case of an additional encryption unit 200 that extracts and stores an image of a predetermined area, converts the extracted area into a predetermined image, and transmits it as secure boot image data for booting, when a booting signal is input by a user's request, The restoration unit 300 for restoring the extracted image stored in the additional encryption unit 200 to the secure boot image data by overwriting the secure boot image data for booting, and applying a preset decryption algorithm, and the restoration According to the decoding unit 400 for decoding the secure boot image data restored by the unit 300 and the decoding result of the decoding unit 400, the integrity determination unit 500 for determining whether the embedded software can be booted normally. It relates to a CBC-based embedded software integrity guarantee system comprising a.

Description

CBC-based embedded software integrity guarantee system and its method {Guaranteeing integrity system and method of embedded software based on Cipher-Block Chaining}

The present invention relates to a CBC-based embedded software integrity guarantee system and a method thereof, and more particularly, to a CBC-based embedded software capable of preventing technology leakage of embedded software and preventing the operation of software by unauthorized users. It relates to an integrity guarantee system and a method thereof.

Secure boot is a security system that prevents the execution of unauthorized programs when booting a computer. In other words, software produced by a manufacturer intended for specific hardware to prevent software leakage and system hacking. It is a technology that uses an encryption algorithm and a sign check method when booting the system in order to run only.

In a typical secure boot process, as shown in FIG. 1, in the embedded software of an embedded system, an encrypted software image (secure boot image, etc.) intended by the manufacturer is stored in a nonvolatile memory (ROM, FLASH, etc.), When a boot signal is input (Power is On), the encrypted software image is transmitted to RAM (DRAM, SRAM, etc.) by the boot code and decrypted. If there is no problem as a result of sign verification, the CPU through the decrypted software image By doing so, the system is started.

The difference between the secure boot process of the embedded software of an embedded system in a field that requires security is the difference between the secure boot process of the embedded software of an embedded system in a field that requires security, in order to protect the contents of the software in the secure boot process. The encrypted image is stored in a nonvolatile memory, and the encrypted image is decrypted before the actual system operation is performed to verify the signature, and the software is operated only when the integrity is verified.

In the conventional encryption method of embedded software, if the encryption key is found, the embedded software can be restored, and binary content can be converted to assembly or higher language for analysis, so that intellectual property rights such as algorithms and architectures are exposed or software is abused. There is a potential problem. In addition, by encrypting the hacked software with an exposed encryption key, there is a possibility that unintended software is driven in the embedded system and even hardware is exploited.

That is, as shown in FIG. 2, when a hacker or a creator intentionally hacks the encrypted software image itself, since the key used for encryption is the same as the decryption encryption key inside the system, decryption is normally performed, Since the encryption key used for signing is also the same as the one inside the system, there is a problem in that the hacked (contaminated) software image is determined as a normal image, and is normally booted and driven.

In this regard, Korean Patent Publication No. 10-2010-0106110 ("Secure boot data integrated management system, metadata generation and verification method for integrated secure boot data management, The recording medium") discloses a technology capable of systematically generating and managing a plurality of secure boot data by integrating and managing secure boot data and verifying integrity.

Korean Patent Publication No. 10-2010-0106110 (Publication date 2010.10.01.)

The present invention was conceived to solve the problems of the prior art as described above, and an object of the present invention is to prevent the technology leakage of embedded software and to prevent the operation of the software by an unauthorized user, based on CBC It is to provide a CBC-based embedded software integrity guarantee system and method that can make unauthorized decryption impossible by performing additional encryption on the encrypted image.

In the CBC-based embedded software integrity guarantee system according to an embodiment of the present invention, in the CBC (Cipher-Block Chaining)-based embedded software integrity guarantee system for secure booting of embedded software, An encryption unit 100 that generates secure boot image data by applying a predetermined encryption algorithm to the input image data, and a predetermined area for the secure boot image data generated by the encryption unit 100 An additional encryption unit 200 that extracts and stores an image, and converts the extracted area into a predetermined image and transmits it as secure boot image data for booting, and a secure boot image for booting when a booting signal is input at the request of a user The restoration unit 300 for restoring the data to secure boot image data by overwriting the extracted image stored in the additional encryption unit 200, and applying a preset decryption algorithm, in the restoration unit 300 It is preferable to include a decoding unit 400 for decoding the restored secure boot image data, and an integrity determination unit 500 for determining whether or not the embedded software can be booted normally, according to a decoding result of the decoding unit 400 Do.

Further, the additional encryption unit 200 extracts and stores images corresponding to a predetermined number of areas of the secure boot image data, and stores images of the areas matching the extracted areas. It is preferable to change to an image to generate the secure boot image data for booting.

Furthermore, the additional encryption unit 200 is configured to include a single write-only memory device (One time writable media), and storing images corresponding to a predetermined region extracted from the secure boot image data in the memory device. desirable.

Furthermore, the restoration unit 300 overwrites the images corresponding to the predetermined area stored in the additional encryption unit 200 to the secure boot image data for booting according to each area, and converts the images corresponding to the predetermined area into the secure boot image data. It is desirable to restore it.

Furthermore, it is preferable that the integrity determination unit 500 determines whether the bootable secure boot image data is abnormal according to the decoding result, and determines whether the embedded software can be booted normally.

In the CBC-based embedded software integrity guarantee method according to an embodiment of the present invention, in the CBC (Cipher-Block Chaining)-based embedded software integrity guarantee method for secure booting of embedded software, In the encryption unit, a secure image generation step of generating secure boot image data by applying a preset encryption algorithm to the input image data (S100), in an additional encryption unit, the secure image generation step (S100) Encrypted image conversion step (S200) of extracting a predetermined area image and converting the extracted area into a secure boot image data for booting with respect to the secure boot image data generated in step S200, at the restoration unit, a user's request When a booting signal is input by, overwrite the images corresponding to a predetermined area extracted, stored and managed in the encrypted image conversion step (S200) to the secure boot image data for booting, and the image data is converted into secure boot image data. In the restoring step (S300) of restoring, the decryption step (S400) of decoding the secure boot image data restored in the restoring step (S300) by applying a preset decryption algorithm in the decoder and in the integrity determination unit, the decryption According to a result of decrypting the secure boot image data in step S400, it is preferable to include an integrity determination step S500 of determining whether the embedded software can be booted normally.

Furthermore, in the encrypted image conversion step (S200), it is preferable to store and manage images corresponding to a predetermined area of the extracted secure boot image data through a separate storage device.

Furthermore, the encrypted image conversion step (S200) extracts and stores images corresponding to a predetermined number of regions among the entire regions of the secure boot image data, and images of regions matching the extracted regions are It is preferable to change to a predetermined image to generate the secure boot image data for booting.

Further, in the restoration step (S300), the images corresponding to the predetermined area stored in the encrypted image conversion step (S200) are overwritten in the secure boot image data for booting according to each area, and the secure boot image It is desirable to restore it to data.

The CBC-based embedded software integrity guarantee system and method of the present invention with the configuration as described above, by performing additional encryption on the image that has been encrypted for booting the embedded software based on CBC, so that unauthorized decryption is impossible. There is an advantage of preventing illegal technology leakage and preventing the operation of software by unauthorized users.

In other words, since it is impossible to illegally decrypt through the encrypted image based on the CBC stored in the ROM/FLASH for booting the embedded software, it is possible to prevent the leakage of illegal software technology and the operation of the software by unauthorized users. There is an advantage to be able to.

In addition, there is an advantage of preventing the illegal use of the hardware from being changed by preventing the operation of illegally altered software by an unauthorized user in a specific hardware.

1 and 2 are exemplary diagrams showing driving of a conventional embedded software integrity guarantee system.
3 is a diagram showing the configuration of a CBC-based embedded software integrity guarantee system according to an embodiment of the present invention.
4 to 6 are exemplary diagrams showing driving of a CBC-based embedded software integrity guarantee system according to an embodiment of the present invention.
7 is a flow chart showing a method of ensuring the integrity of embedded software based on CBC according to the present invention.

Hereinafter, a CBC-based embedded software integrity guarantee system and method of the present invention will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms. In addition, the same reference numbers throughout the specification indicate the same elements.

In this case, unless there are other definitions in the technical terms and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may unnecessarily obscure are omitted.

In addition, a system refers to a set of components including devices, devices, and means that are organized and regularly interact to perform a required function.

CBC-based embedded software integrity guarantee system and method according to an embodiment of the present invention, even if an encryption key is leaked during a secure boot process, the encrypted software image (secure boot image) existing in the system is There is an advantage in that decryption is impossible, so that it is impossible to run hacking software encrypted with the leaked encryption key.

This is because the CBC encryption algorithm is used, and if even 1 bit of the image is modulated, normal decryption is impossible.

Specifically, a block cipher is a symmetric key encryption system that encrypts confidential information in blocks of a fixed size, and the security text is a repetitive rotation of plain text. It is produced as a function, and the input of the rotation function consists of a key and an Output of previous round.

CBC (Cipher-Block Chaining) is one of these block ciphers. Each block performs an XOR operation with the encryption result of the previous block before being encrypted, and IV (initialization vector) is used for the first block. It is done. In the case of the initialization vector, since the output result is always the same, a different IV must be used for each encryption.

The CBC method is a currently widely used block cipher operation method, and because the encryption input value depends on the previous result, parallelization is impossible, but in the case of decryption, each block can be decrypted and then recovered through XOR operation with the previous encryption block. Therefore, parallelization is possible.

The CBC encryption algorithm used in many fields has a characteristic that if even 1 bit of the entire encrypted image is altered, decryption is attempted with the correct encryption key, decryption is performed with a completely different value from the original.

Accordingly, the CBC-based embedded software integrity guarantee system and method according to an embodiment of the present invention are utilized to prevent the hacking firmware drive of the embedded software by using the CBC encryption characteristic.

That is, the original software image is encrypted using a CBC-type encryption algorithm, and a part of the encrypted image is stored in an internal memory or high-security storage implemented in an FPGA (Field Programmable Gate Array) instead of a non-volatile memory. After filling the binary at the location corresponding to the stored portion of the encrypted image with meaningless values, the image is stored in a nonvolatile memory for booting.

When the power is turned on, the boot loader loads the image stored in the nonvolatile memory into RAM, retrieves the image block stored in the FPGA or a separate storage, and overwrites the image loaded in the RAM at the corresponding location. After that, decryption proceeds.

At this time, even if the modified firmware is encrypted by the exposed encryption key and stored in the nonvolatile memory, the hacked image will be altered by the overwritten image block, and then decryption is attempted with the correct encryption key. , The decoding is performed in the form of an abnormal value other than the original image due to the characteristics of the CBC algorithm, making it impossible to drive the hacking firmware.

In addition, even if the booting image normally encrypted by the original creator is read by a device such as a flash loader for hacking, a part of the image is altered, so even if the encryption key is exposed, normal decryption is not possible. Preservation becomes possible.

If this is applied to the field of unmanned aerial vehicles such as drones, it is possible to prevent the leakage of software technology through analysis of the software embedded in the crashed aircraft, and the advantage of preventing the reuse of the aircraft by unauthorized users. have.

As shown in FIG. 3, the CBC-based embedded software integrity guarantee system according to an embodiment of the present invention includes an encryption unit 100, an additional encryption unit 200, a restoration unit 300, a decryption unit 400, and It is preferably configured to include an integrity determination unit 500, and relates to an embedded software integrity guarantee system based on Cipher-Block Chaining (CBC) for secure booting of embedded software.

To learn more about each configuration,

It is preferable that the encryption unit 100 generates secure boot image data by applying a preset encryption algorithm to the input image data based on CBC.

In this case, the image data is preferably input by a user (producer, etc.), and the secure boot image refers to an encrypted software image intended by the manufacturer, exemplified by FIG. 1.

In this case, as the preset encryption algorithm, it is preferable to use an encryption algorithm such as AEC/DES, and it is preferable to calculate a sign using an algorithm such as SHA/MD5.

The role of the encryption unit 100 is performed almost similar to the operation of performing encryption in a conventional embedded software integrity guarantee system.

However, in the CBC-based embedded software integrity guarantee system according to an embodiment of the present invention, as described above, it is preferable to once again encrypt a software image that has already been encrypted based on CBC.

This operation is preferably performed through the additional encryption unit 200.

As shown in FIG. 4, the additional encryption unit 200 extracts a part of the encrypted software image, stores it in a specific block of the FPGA, or a separate storage with high security and unchangeability, and extracts the It is desirable to perform image change with a random value that is meaningless at the location.

That is, the additional encryption unit 200 extracts a predetermined area image from the secure boot image data generated by the encryption unit 100 and stores it in an FPGA or a separate storage with high security, and the extracted corresponding area It is preferable to generate secure boot image data for booting by changing to a predetermined image (insignificant random value, etc.).

The secure boot image data for booting generated in this way is stored in a nonvolatile memory, so that when the power is turned on later, the boot loader loads the image stored in the nonvolatile memory into RAM and performs subsequent operations. .

In detail, the additional encryption unit 200 extracts images corresponding to a predetermined number of predetermined areas among the entire areas of the secure boot image data, and is used in an FPGA or a separate storage with high security (only a single record is possible). It is stored in a memory device (one time writable media is most preferable.), and the extracted images of the regions matching the regions are changed to a predetermined image (insignificant random value, etc.) to generate secure boot image data for booting. It is desirable to do it.

When a boot signal is input by a user's request, that is, when the power is turned on, the restoration unit 300 stores the secure boot image data for booting stored in a nonvolatile memory in the additional encryption unit 200, and Existing extracted images are overwritten to restore secure boot image data.

That is, in the case of a conventional embedded software integrity guarantee system, the secure boot image data for booting stored in the nonvolatile memory is immediately decoded, and the decoding result image is used to determine whether the embedded software can be booted normally. do.

However, as described above, when the hacking image encrypted by the leaked encryption key is stored as secure boot image data for booting, it is not possible to prevent the hacking software from being driven by this. In other words, it is impossible to prevent the operation of hacking software generated by the leaked encryption key.

In contrast, in the CBC-based embedded software integrity guarantee system according to an embodiment of the present invention, through the restoration unit 300, images corresponding to the predetermined area stored in the additional encryption unit 200 are each It is preferable to overwrite the secure boot image data for booting according to the region to restore the secure boot image data.

In other words, as shown in FIG. 5, the secure boot image data for booting stored in the nonvolatile memory is received, and extracted images stored in the memory device capable of only writing the single record to the secure boot image data for booting are transferred. By overwriting, the first encrypted image is restored.

At this time, if the software image is encrypted by the normal encryption key, as shown in FIG. 5, the software image encrypted by the normal encryption key will be restored, but if the software image is encrypted by the encryption key leaked by a hacker, As shown in Fig. 6, the corrupted encrypted software image is restored.

That is, as shown in FIG. 5, by receiving secure boot image data for booting stored in a nonvolatile memory, overwriting the extracted images stored in the memory device capable of only single recording to the original location, encryption You can restore the original image.

In this case, when decoding the secure boot image data restored by the restoration unit 300 by applying a preset decryption algorithm (algorithm setting such as AES/DES) in the decryption unit 400, a normal decrypted software image Will be performed as.

Accordingly, in the integrity determination unit 500, if there is no problem as a result of the decoded software image and sign verification according to the decoding result of the decoding unit 400, it determines that the embedded software can be booted normally, and boots normally. Is controlled to be performed.

However, as shown in FIG. 6, the secure boot image data for booting stored in the nonvolatile memory was received, and the extracted images stored in the memory device capable of only single writing were overwritten to the original location. Since the secure boot image data for booting stored in the volatile memory itself is contaminated (damaged) image data created with an encryption key that has already been leaked by a hacker, the encrypted image cannot be restored to its original state. However, the restoration unit 300 cannot determine this, and when the secure boot image data restored by the restoration unit 300 is decoded by applying a preset decryption algorithm through the decryption unit 400 , It is executed as an abnormal decoded software image.

The decryption unit 400 also cannot determine this, and the integrity determination unit 500 determines that the sign of the abnormally decrypted software image as a hacking software is inconsistent, and stops booting.

At this time, the extracted images stored in the memory device capable of only single recording are values recorded in one-time writable media during normal system development, and thus cannot be tampered with by a hacker.

That is, in other words, the CBC-based embedded software integrity guarantee system according to an embodiment of the present invention extracts a part of an image encrypted by the CBC method and stores it in a separate space, and the value of the part extracted from the encrypted image Is changed to a random value. That is, since a part of the encrypted image is transformed into a random value in the software image generation procedure, there is an advantage that normal decryption is impossible even if the encryption key is leaked due to the characteristic of the CBC encryption method.

In addition, it is also possible to prevent hackers from running modulated software on certain hardware. That is, since certain software is encrypted, a part is stored in an FPGA, etc., and a part of the software is overwritten with the saved value during operation, it is impossible to decrypt the encrypted software except for unintended software. That is, even if the image is encrypted by the leaked encryption key, the image encrypted by the leaked encryption key is deformed as the boot loader overwrites the value of the extracted portion, making normal decryption impossible.

7 is a flow chart showing a CBC-based embedded software integrity guarantee method according to an embodiment of the present invention, the CBC-based embedded software integrity guarantee method according to an embodiment of the present invention, a secure image generation step (S100), It is preferable to consist of an encrypted image conversion step (S200), a restoration step (S300), a decryption step (S400), and an integrity determination step (S500).

To learn more about each step,

In the secure image generating step (S100), it is preferable that the encryption unit 100 generates the secure boot image data by applying a preset encryption algorithm to the input image data based on CBC.

In this case, the image data is preferably input by a user (producer, etc.), and the secure boot image refers to an encrypted software image intended by the manufacturer, exemplified by FIG. 1.

In this case, as the preset encryption algorithm, it is preferable to use an encryption algorithm such as AEC/DES, and it is preferable to calculate a sign using an algorithm such as SHA/MD5.

In the step of converting the encrypted image (S200), the additional encryption unit 200 extracts a part of the encrypted software image and stores it in a specific block of the FPGA or a separate storage that is immutable and has high security. , It is preferable to convert the image into the secure boot image data for booting by performing image change at a random value that is meaningless to the extracted corresponding position.

Specifically, in the encrypted image conversion step (S200), a predetermined area image is extracted from the secure boot image data generated by the secure image generating step (S100) and stored in an FPGA or a separate high-security storage. In addition, it is preferable to convert/generate the secure boot image data for booting by changing the extracted corresponding region to a predetermined image (a meaningless random value, etc.).

The secure boot image data for booting generated in this way is stored in a nonvolatile memory, so that when the power is turned on later, the boot loader loads the image stored in the nonvolatile memory into RAM and performs subsequent operations. .

The encrypted image conversion step (S200) extracts images corresponding to a predetermined area as many as a preset number from among the entire areas of the secure boot image data, and uses an FPGA or a separate storage with high security (a memory device capable of only writing a single record). One time writable media) is most preferable.), and the extracted images of the regions matching the regions are changed to a predetermined image (insignificant random value, etc.) to generate secure boot image data for booting. Do.

In the restoration step (S300), when a booting signal is input by the user's request, that is, when the power is turned on, the restoration unit 300 encrypts the secure boot image data for booting stored in a nonvolatile memory. Images corresponding to a predetermined area extracted, stored and managed in the image conversion step S200 are overwritten to restore secure boot image data.

In other words, the restoration step (S300) receives the secure boot image data for booting stored in the nonvolatile memory, and overwrites the extracted images stored in the memory device capable of only writing the single record to the secure boot image data for booting. By writing, the first encrypted image is restored.

At this time, if the software image is encrypted by the normal encryption key, as shown in FIG. 5, the software image encrypted by the normal encryption key will be restored, but if the software image is encrypted by the encryption key leaked by a hacker, As shown in Fig. 6, the corrupted encrypted software image is restored.

That is, as shown in FIG. 5, by receiving secure boot image data for booting stored in a nonvolatile memory, overwriting the extracted images stored in the memory device capable of only single recording to the original location, encryption You can restore the original image.

In this case, through the decoding step (S400), when the decoding unit 400 applies a preset decoding algorithm to decode the secure boot image data restored by the restoration step (S300), normal decoding It is executed with the software image.

Accordingly, in the integrity determination step (S500), in the integrity determination unit 500, according to the decryption result of the secure boot image data by the decoding step (S400), there is no problem as a result of the decoded software image and the sign verification result. In this case, it is determined that the embedded software can be booted normally, and the booting is controlled so that the booting is normally performed.

However, unlike this, as shown in FIG. 6, by receiving the secure boot image data for booting stored in the nonvolatile memory, the extracted images stored in the memory device capable of only single writing are overwritten to the original location. However, since the secure boot image data for booting stored in the nonvolatile memory itself is contaminated (damaged) image data created with an encryption key that has already been leaked by a hacker, the encrypted image cannot be restored to its original state.

Therefore, even if the restored secure boot image data is decoded by applying a preset decoding algorithm through the decoding step (S400), it is performed as an abnormal software image.

Accordingly, in the integrity determination step (S500), according to the decryption result of the secure boot image data by the decryption step (S400), the sign verification result of the abnormally decoded software image, inconsistency, is determined as hacking software, It stops booting.

At this time, the extracted images stored in the memory device capable of only single recording are values recorded in one-time writable media during normal system development, and thus cannot be tampered with by a hacker.

As described above, in the present invention, specific matters such as specific components and the like have been described by the drawings of limited embodiments, but this is provided only to help a more general understanding of the present invention, and the present invention is limited to the above-described embodiment. It is not, and those of ordinary skill in the field to which the present invention pertains can make various modifications and variations from this description.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be determined, and all things that are equivalent or equivalent to the scope of the claims as well as the claims to be described later belong to the scope of the spirit of the present invention. .

100: encryption unit
200: additional encryption unit
300: restoration unit
400: decryption unit
500: integrity determination unit

Claims (9)

In the embedded software integrity guarantee system based on Cipher-Block Chaining (CBC) for secure booting of embedded software,
An encryption unit 100 for generating secure boot image data by applying a predetermined encryption algorithm to the input image data;
An additional encryption unit 200 for extracting and storing a predetermined area image for the secure boot image data generated by the encryption unit 100, changing the extracted area to a predetermined image, and transmitting it as secure boot image data for booting. );
When a booting signal is input by a user's request, a restoration unit 300 that overwrites the extracted image stored in the additional encryption unit 200 to the secure boot image data for booting to restore the secure boot image data. );
A decoding unit 400 for decoding the secure boot image data restored by the recovery unit 300 by applying a preset decoding algorithm; And
An integrity determination unit 500 that determines whether or not the embedded software can be booted normally according to the decoding result of the decoding unit 400;
CBC-based embedded software integrity guarantee system comprising a.
The method of claim 1,
The additional encryption unit 200
Extracting and storing images corresponding to a predetermined area as many as a preset number among the entire areas of the secure boot image data,
CBC-based embedded software integrity guarantee system, characterized in that the extracted images of the regions matching the regions are changed to a predetermined image to generate the secure boot image data for booting.
The method of claim 2,
The additional encryption unit 200
It is composed of a single write-only memory device (One time writable media),
CBC-based embedded software integrity guarantee system, characterized in that storing images corresponding to a predetermined region extracted from the secure boot image data in the memory device.
The method of claim 2,
The restoration unit 300 is
CBC-based embedded, characterized in that images corresponding to the predetermined area stored in the additional encryption unit 200 are overwritten in secure boot image data for booting according to each area, and are restored as secure boot image data. Software integrity assurance system.
The method of claim 4,
The integrity determination unit 500
CBC-based embedded software integrity guarantee system, characterized in that by determining whether the secure boot image data for booting is abnormal according to the decoding result, and determining whether the embedded software can be booted normally.
In the method of ensuring the integrity of embedded software based on Cipher-Block Chaining (CBC) for secure booting of embedded software,
A secure image generation step (S100) of generating secure boot image data by applying a predetermined encryption algorithm to the input image data by the encryption unit;
An additional encryption unit extracts a predetermined area image from the secure boot image data generated in the secure image generation step (S100), converts the extracted area into a predetermined image, and converts the encrypted image into secure boot image data for booting. Conversion step (S200);
When a booting signal is input by the user's request, the restoration unit overwrites images corresponding to a predetermined area extracted, stored and managed in the encrypted image conversion step (S200) to the secure boot image data for booting. ) To restore the secure boot image data (S300);
A decoding step (S400) of decoding the secure boot image data restored in the recovery step (S300) by applying a predetermined decoding algorithm in the decoding unit; And
Integrity determination step (S500) of determining whether the embedded software can be booted normally according to a result of decoding the secure boot image data by the decoding step (S400);
CBC-based embedded software integrity guarantee system, characterized in that consisting of.
The method of claim 6,
The encrypted image conversion step (S200)
CBC-based embedded software integrity guarantee system, characterized in that images corresponding to a predetermined area of the extracted secure boot image data are stored and managed through a separate storage device.
The method of claim 7,
The encrypted image conversion step (S200)
Extracting and storing images corresponding to a predetermined area as many as a preset number among the entire areas of the secure boot image data,
CBC-based embedded software integrity guarantee method, characterized in that the extracted images of the regions matching the regions are changed to a predetermined image to generate the secure boot image data for booting.
The method of claim 8,
The restoration step (S300) is
CBC-based, characterized in that the images corresponding to the predetermined area stored in the encrypted image conversion step (S200) are overwritten in the secure boot image data for booting according to each area, and are restored to the secure boot image data. How to ensure the integrity of your embedded software.

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