CN113420309B - Lightweight data protection system based on national secret algorithm - Google Patents

Abstract

The invention discloses a lightweight data protection system based on a national secret algorithm, comprising an encryption card in a hardware part, an embedded firmware program in a software part, and upper computer software, wherein: the encryption card adopts a security chip as the main control chip, At the same time, it undertakes the computing task of encryption and decryption, and the data communication and circuit power supply of the encryption card are realized by the USB interface; the binary file of the embedded firmware program is stored in the Flash of the encryption card for the execution of the security chip; and the host computer software is in the It runs in the host computer, and realizes the communication with the encryption card through the way of USB to serial port. The two-level key management scheme designed by the invention not only ensures the security of the key, prevents the security threat caused by the theft of the key, but also brings convenience to the use of the user; under the condition of low cost, it can achieve obvious Simple and secure in use, providing lightweight services for encryption and decryption, digital signature and verification of local files on the computer.

Description

Lightweight data protection system based on national secret algorithm

technical field

The invention relates to the technical field of information security, in particular to a lightweight data protection system based on a national secret algorithm.

Background technique

Currently, data protection can be implemented by an encryption system consisting of software or hardware. The encryption system implemented by software refers to the use of software programs to realize the encryption and decryption protection of data. Although its development cost is low and maintenance is convenient, it occupies more computer resources, the encryption program is easy to be monitored and tampered with, and the key management is difficult, so the security is not high. Moreover, the encryption operation speed implemented by hardware is several times faster than that of software.

For example, the software encryption may be implemented by a file filtering-driven personal data security protection system under Windows system, and the encryption and decryption operations are all implemented by software. There are also some file encryption systems that are implemented through a combination of software and hardware. The USB Key manages the key and encrypts the session key, but in fact, it also encrypts and decrypts files through software.

The encryption system implemented by hardware refers to the use of special hardware devices that can execute cryptographic algorithms to protect data. It is difficult for the outside world to intervene in the computing process of the hardware device, and it cannot directly access the sensitive information in it. The functions of the hardware device can only be called through a predefined interface. Compared with software, hardware encryption system has greater advantages in resisting external attacks, protecting the security of keys, and speed of encryption and decryption operations. Hardware-implemented cryptosystems have the following common examples.

(1) Encrypt the data in the hard disk to provide data integrity verification and identity authentication. (2) The encryption system based on USB Key uses the built-in security chip of USB Key to perform identity verification, data encryption and decryption operations and integrity verification.

Disadvantages of the prior art:

First, the encryption technology is implemented in software. Its disadvantage is that it takes up more computer CPU resources. This is because the encryption algorithm is a very complex operation and requires a lot of CPU participation, especially when the encryption demand explodes. In addition, its encryption program is easy to be monitored and tampered with, because it does not have a relatively isolated security environment, there is a danger of computer virus invasion, and the security is not high. Furthermore, the speed of software-implemented encryption is relatively slow, because it is operated by CPU. Compared with the encryption algorithm implemented by hardware chip circuit, it is quite slow and slower. several orders of magnitude.

Then, use hardware-implemented encryption techniques. Its security is very high, and there are many application methods. As I mentioned in the background introduction, there are many changes in the form of FPGA and security chips. However, there are currently very few implementations that can purely encrypt files local to the computer, and its cost and simplicity are usually still a problem.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a lightweight data protection system based on a national secret algorithm, which achieves obvious simplicity and safety in use under the condition of low cost.

In order to realize the above-mentioned tasks, the present invention adopts the following technical solutions:

A lightweight data protection system based on a national secret algorithm, comprising an encryption card in the hardware part, an embedded firmware program in the software part, and host computer software, wherein:

The encryption card adopts the security chip as the main control chip, and undertakes the operation task of encryption and decryption at the same time. The data communication and circuit power supply of the encryption card are realized by the USB interface; the encryption card includes:

Security chip, which integrates the CPU and the computing acceleration core of the national secret SM2, SM3, and SM4 algorithms, has a true random number generator, as well as serial and SPI communication interfaces; power management module, used to convert external input voltages , to supply the security chip and other modules and interfaces; the USB to serial port module is used to realize the communication between the host computer and the security chip, and the USB is also used as the power supply interface; the EEPROM module is the memory of the user's account and key data ;Flash module, which is the memory of embedded firmware program; JTAG interface, is the debugging interface, used for downloading firmware and debugging program;

The binary file of the embedded firmware program is stored in the Flash of the encryption card for the execution of the security chip; and the host computer software is run in the host computer, and the communication with the encryption card is realized by means of USB to serial port, wherein:

The embedded firmware program includes a top-level module and a bottom-level module. The top-level module contains the encryption card work function; the encryption card work function is used to realize the connection and disconnection of the protection system, and to provide users with registration, login, reset, encryption and decryption services; the bottom module Contains a variety of drivers, including SM2, SM3, SM4 operation acceleration core driver, serial port and GPIO driver, random number generator driver and driver using IIC to read and write EEPROM module; the top-level module continuously calls the bottom-level module to achieve complete workflow;

Key management methods include:

The user needs to register an account on the encryption card first, and customize an 8-digit PIN code in the range of 0 to 9. The PIN code is not only used as the user's login password, but also used for authentication and key management;

The encryption card continuously performs two SM3 operations on the PIN code, respectively obtaining a 256-bit message digest of the first operation and a message digest of the second operation; after that, the second message digest is first stored in the EEPROM module , as the PIN code comparison standard when the user logs in in the future;

The encryption card generates a random pair of SM2 public and private keys, and then uses the first 128 bits of the message digest obtained by the first SM3 operation of the PIN code as the symmetric key to encrypt the SM2 private key with the SM4 algorithm, and the SM2 public key is encrypted. The key is not encrypted; then the plaintext of the public key of SM2 and the ciphertext of the encrypted private key of SM2 are stored in the EEPROM module;

The encryption card randomly generates an SM4 symmetric key, uses the first 128 bits of the message digest obtained by the first SM3 operation of the PIN code to encrypt the SM4 symmetric key with the SM4 algorithm, and finally encrypts the encrypted SM4 symmetric key. The file is stored in the EEPROM module.

Further, the host computer software is divided into five panels: a control panel, a login panel, an encryption panel, a decryption panel and a file display panel, wherein:

The control panel is used to configure the communication port, choose to connect/disconnect the device, and enter/exit the encryption mode; the login panel is used to provide the user login interface and display the login status; the encryption panel is used to select the path of the plaintext file, save the ciphertext file The path, the path to save the SM2 public key, and the path to save the SM2 digital signature, and control the start of encryption; the decryption panel is used to select the path of the ciphertext file, the path of the SM2 digital signature, the path of the SM2 public key, and the path to save the plaintext file. , and control the start of decryption; the file display panel is used to display the plaintext before encryption/encrypted ciphertext and the ciphertext before decryption/decrypted plaintext.

Further, the management of the key is divided into two levels. The first 128 bits of the message digest obtained by the first SM3 operation of the PIN code are the first-level key; and the randomly generated SM2 private key and SM4 symmetric key, That is, the second-level key; the first-level key encrypts the second-level key, and then saves the ciphertext of the key; and when the second-level key needs to be used, the ciphertext of the key must be encrypted first. Take it out and decrypt it with the primary key before it can be used.

Further, the process of encryption and decryption and digital signature and verification is as follows:

In the encryption card, the plaintext is first encrypted by SM4 to generate the ciphertext, and then the message digest of the ciphertext is generated by the SM3 algorithm, and then the SM2 digital signature is performed on the message digest, and finally the digital signature and the ciphertext are sent to the host computer together;

When verifying the signature, first obtain the message digest of the original ciphertext through the SM2 signature verification algorithm for the digital signature, and then obtain the message digest of the received ciphertext through the SM3 algorithm, and then compare the above two message digests, and verify if they are the same. If successful, SM4 decrypts the ciphertext to obtain the plaintext, and sends the plaintext to the upper computer; otherwise, the verification fails, and subsequent decryption is not performed.

Further, at the beginning of the operation of the host computer, only the control panel is displayed. The user must connect the device, register (needed for the first use or after reset), and successfully log in to perform encryption and decryption; the user can use the reset function to clear the encryption card. All account and key data for .

Further, the security chip adopts the IoT security chip CE2343P7 of Foshan Xinzhu Microelectronics Co., Ltd.

Further, the embedded firmware program further includes a board-level support package, and the board-level support package is used to provide an environment for the firmware to run.

Compared with the prior art, the present invention has the following technical characteristics:

1. The system of the present invention is first a hardware encryption scheme, including the design of software and hardware. It has the advantages of hardware encryption. Its biggest purpose is to achieve obvious use under the condition of low cost. Its simplicity and security, it focuses on lightweight services that only encrypt, decrypt, digitally sign and verify local files on the computer. Moreover, the present invention is completely designed based on Chinese commercial cryptographic algorithms SM2, SM3 and SM4. It does not use foreign cryptographic algorithms, which has significance in national security. After all, cryptographic algorithms are not foreign, but China's own. It is also meaningful to support the promotion of our domestically produced encryption algorithms, and the designs of current similar products are seldom or almost entirely based on national encryption algorithms.

2. The present invention designs a very simple and effective two-level key management scheme based on Chinese commercial cryptographic algorithms SM2, SM3, and SM4, which not only ensures the security of the key, but also prevents security threats from being stolen due to the key being stolen. Bring convenience to users. Designed a very practical and safe file encryption and decryption, digital signature and verification process scheme; designed the complete hardware circuit of the encryption card and the software that works together with the encryption card. The two-factor authentication scheme (encrypted card itself and PIN code, which constitute a two-factor authentication scheme) ensures the uniqueness of the user's identity and is convenient for use and management.

Description of drawings

Fig. 1 is the overall design frame diagram of the present invention;

Fig. 2 is the schematic diagram of the hardware circuit of the encryption card;

Figure 3 is the PCB diagram of the encryption card;

Figure 4 is the overall design framework diagram of the software;

Fig. 5 is the interface diagram of the host computer software;

Fig. 6 is the key management flow chart;

Fig. 7 is the flow chart of encryption and digital signature generation;

Figure 8 is a flow chart of digital signature verification and decryption.

Detailed ways

The functional requirements of the lightweight data protection system based on the national secret algorithm provided by the present invention have the following four points:

(1) Requirements for encryption and decryption. Based on the national secret algorithm, the file data in the computer is encrypted and decrypted using special hardware to ensure the security of the data.

(2) Digital signature and verification. After the user encrypts the file data, a corresponding digital signature is generated. Before the user decrypts the data, the corresponding digital signature needs to be verified to confirm the origin and integrity of the data, so as to ensure that the data is encrypted by the user and has not been tampered with or destroyed.

(3) User authentication. Users who operate the system need to be authenticated, and only users who have passed the authentication can use the system to encrypt and decrypt data, digitally sign, and other operations.

(4) Key management function. The file encryption and decryption system needs to have the function of key storage and management. The user's SM2 private key and SM4 symmetric key can only be stored in the encryption hardware device and cannot be exported to ensure the security of the key. Moreover, user account information also needs to be managed and stored in encrypted hardware devices.

The system also needs to implement the following 2 non-functional requirements:

(1) Easy to operate. It is necessary to implement a concise and easy-to-operate user interface with stable operation and improve user experience.

(2) Low cost and light weight. Reduce the cost and complexity of the design while ensuring the security and practicability of the system.

Overall design division:

In order to meet the above design requirements, it is determined that the system is composed of encryption hardware devices (hereinafter referred to as encryption cards), embedded firmware programs, and upper computer software. This system uses SM4 algorithm to encrypt and decrypt file data; uses SM2 algorithm and cooperates with SM3 algorithm to realize digital signature and verification to meet the needs of data source and integrity verification; PIN) to realize the identity authentication of the user; by designing a two-level key management mechanism, and encrypting the key and storing it in the memory EEPROM of the encryption card, the function of key management is realized; by designing a reasonable and smooth graphical user interface, Ease of operation is achieved.

The specific design is divided as follows:

(1) Design the hardware circuit of the encryption card.

(2) Design the embedded firmware program of the encryption card, and write the program of the encryption card according to the selected hardware resources of the main control security chip and the board-level development kit to realize the encryption and decryption of data, digital signature and verification, and key management. , identity authentication and other functions.

(3) The upper computer software with graphical user interface is designed to cooperate with the work of the encryption card and facilitate user operation.

According to the above overall design division, it is determined that the system is composed of hardware and software. The specific design framework is shown in Figure 1.

Hardware circuit design of encryption card:

Combined with the design goals of low cost and light weight, the encryption card uses the security chip as the main control chip, and the chip undertakes the computing tasks of encryption and decryption. Both data communication and circuit power supply rely on the USB interface. The hardware circuit of the encryption card specifically includes the following six parts:

(1) The main control security chip adopts the IoT security chip CE2343P7 of Foshan Xinzhu Microelectronics Co., Ltd. The chip integrates the CPU and the computing acceleration core of the national secret SM2, SM3, and SM4 algorithms, has a true random number generator, and communication interfaces such as serial ports and SPI.

(2) The power management module converts the externally input voltage to supply other modules for use.

(3) The USB to serial port module realizes the communication between the host computer and the security chip, and the USB also serves as the power supply interface.

(4) The EEPROM module is the storage of the user's account and key data.

(5) The Flash module is the memory of the embedded firmware program.

(6) The JTAG interface is a debugging interface for downloading firmware and debugging programs.

The schematic design of the encryption card hardware circuit is shown in Figure 2:

According to the above circuit, the PCB diagram is generated and the layout and wiring are designed. The final PCB diagram (front) is shown in Figure 3; the length and width of the encryption card PCB are about 52mm and 28mm, which are small in size and easy to carry.

software design:

The overall design of the software:

The software of this system consists of embedded firmware program and host computer software. In actual application, the binary file of the embedded firmware program is stored in the Flash of the encryption card for the security chip to execute; and the host computer software is run in the host computer. , to realize the communication with the encryption card by means of USB to serial port. The overall design framework of the software is shown in Figure 4.

The embedded firmware program is divided into a top-level module and a bottom-level module. The top-level module is the Main function that mainly includes the encryption card work function. The encryption card work function can realize the connection and disconnection of the device, and provide users with registration, login, reset, encryption and decryption (including digital signature and verification) services. The underlying modules are mainly various drivers, including SM2, SM3, SM4 arithmetic acceleration core drivers, serial port and GPIO drivers, random number generator drivers, and drivers for reading and writing EEPROM using IIC. The board support package provides the environment in which the firmware runs. The top-level module implements a complete workflow by continuously calling the bottom-level module.

The host computer software is implemented based on the GUIDE tool of MATLAB, with a simple graphical user interface, divided into five panels: control panel, login panel, encryption panel, decryption panel and file display panel, as shown in Figure 5 is the runtime control Panel, encryption panel and file display panel:

The control panel is used to configure the communication port, choose to connect/disconnect the device, and enter/exit the encryption mode; the login panel is used to provide the user login interface and display the login status; the encryption panel is used to select the path of the plaintext file, save the ciphertext file The path, the path to save the SM2 public key, and the path to save the SM2 digital signature, and control the start of encryption; the decryption panel is used to select the path of the ciphertext file, the path of the SM2 digital signature, the path of the SM2 public key, and the path to save the plaintext file. , and control the start of decryption; the file display panel is used to display the plaintext before encryption/encrypted ciphertext and the ciphertext before decryption/decrypted plaintext.

At the beginning of the operation of the host computer, only the control panel is displayed. The user must connect the device, register (needed for the first use or the first use after reset), and successfully log in to perform encryption and decryption. In addition, the user can use the reset function to clear all account and key data of the encrypted card. The file display panel can view the text data before and after encryption and decryption.

Key management and authentication scheme:

The system encrypts and decrypts data based on SM4 algorithm and performs digital signature and verification based on SM2 algorithm. Then an SM4 symmetric key and a pair of SM2 public and private keys must be generated. The key is generated by a true random number generator in the security chip of the encryption card, which ensures the unpredictability of the key. In order to protect the security of the system and keys, an ingenious and simple two-level key management scheme is designed, and the method of two-factor authentication is adopted. The specific key management process is shown in Figure 6.

The key management process is described as follows:

Step 1, the user needs to register an account on the encryption card first, and customize an 8-digit personal identification password (PIN code) with a number range between 0 and 9. The PIN code is not only used as the user's login password, but also used for authentication and key management.

Step 2: The encryption card performs two consecutive SM3 operations on the PIN code to obtain a 256-bit message digest of the first operation and a message digest of the second operation, respectively. After this, the second message digest is stored in the EEPROM first, as the PIN code comparison standard when the user logs in later.

Step 3, the encryption card generates a pair of random SM2 public and private keys. Next, use the first 128 bits of the message digest obtained by the first SM3 operation of the PIN code as the symmetric key to encrypt the private key of SM2 with the SM4 algorithm. The public key of SM2 is not encrypted. Then store the SM2 public key plaintext and the encrypted SM2 private key ciphertext into the EEPROM.

Step 4, the encryption card randomly generates a symmetric key of SM4. The first 128 bits of the message digest obtained by the first SM3 operation of the PIN code are used to encrypt the SM4 symmetric key with the SM4 algorithm. Finally, the ciphertext of the encrypted SM4 symmetric key is stored in the EEPROM.

In general, the key management is divided into two levels. The first 128 bits of the message digest obtained by the first SM3 operation of the PIN code are the first-level key; and the randomly generated SM2 private key and SM4 symmetric key , which is the second-level key. The primary key encrypts the secondary key, and then saves the ciphertext of the key; when the secondary key needs to be used, the ciphertext of the key must be taken out first, and the primary key is used for It can only be used after decryption.

This scheme has the following three advantages:

(1) Under the premise of light weight, the security of all keys is guaranteed. Based on the one-way characteristic of the SM3 algorithm, the first message digest or the PIN code cannot be obtained by reverse derivation from the second message digest of the PIN code.

(2) Two-factor authentication, effectively ensuring the security of the system. The user must have both an encryption card and a PIN code in order to use the system normally.

(3) Provides a good user experience. Users only need to memorize an 8-digit PIN code and keep the encryption card hardware device, which is simple and convenient.

The process of encryption and decryption and digital signature and verification:

This design comprehensively uses the national secret SM2, SM3 and SM4 algorithms. In the encryption card, the plaintext is encrypted by SM4 to generate the ciphertext, and then the message digest of the ciphertext is generated by the SM3 algorithm, and then the SM2 digital signature is performed on the message digest, and finally the digital signature and the ciphertext are sent to the host computer. The whole process is shown in Figure 7.

When verifying the signature, first obtain the message digest of the original ciphertext through the SM2 signature verification algorithm for the digital signature, and then obtain the message digest of the received ciphertext through the SM3 algorithm, and then compare the above two message digests, and verify if they are the same. If successful, SM4 decrypts the ciphertext to obtain the plaintext, and sends the plaintext to the upper computer; otherwise, the verification fails, and subsequent decryption is not performed. The whole process is shown in Figure 8.

The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application, and should be included in the application. within the scope of protection.

Claims (7)

1. a lightweight data protection system based on national secret algorithm, is characterized in that, comprises the encryption card of hardware part and the embedded firmware program of software part and the host computer software, wherein: The encryption card adopts the security chip as the main control chip, and undertakes the operation task of encryption and decryption at the same time. The data communication and circuit power supply of the encryption card are realized by the USB interface; the encryption card includes: A security chip, which integrates the CPU and the computing acceleration core of the National Secret SM2, SM3, and SM4 algorithms, has a true random number generator, and a serial port and SPI communication interface; a power management module, used for external input voltage It is converted to supply the security chip and other modules and interfaces; the USB to serial port module is used to realize the communication between the host computer and the security chip, and the USB is also used as the power supply interface; the EEPROM module is the user's account and key data The flash module is the memory of the embedded firmware program; the JTAG interface is the debugging interface for downloading firmware and debugging programs; The binary file of the embedded firmware program is stored in the Flash of the encryption card for the execution of the security chip; and the host computer software is run in the host computer, and the communication with the encryption card is realized by means of USB to serial port, wherein: The embedded firmware program includes a top-level module and a bottom-level module. The top-level module contains the encryption card work function; the encryption card work function is used to realize the connection and disconnection of the protection system, and to provide users with registration, login, reset, encryption and decryption services; the bottom module Contains a variety of drivers, including SM2, SM3, SM4 operation acceleration core driver, serial port and GPIO driver, random number generator driver and driver using IIC to read and write EEPROM module; the top-level module continuously calls the bottom-level module to achieve complete workflow; Key management methods include: The user needs to register an account on the encryption card first, and customize an 8-digit PIN code in the range of 0 to 9. The PIN code is not only used as the user's login password, but also used for authentication and key management; The encryption card first performs an SM3 operation on the PIN code, and then performs an SM3 operation on the operation result to obtain a 256-bit message digest of the first operation and a message digest of the second operation; The next message digest is stored in the EEPROM module, as the PIN code comparison standard when the user logs in later; The encryption card generates a random pair of SM2 public and private keys, and then uses the first 128 bits of the message digest obtained by the first SM3 operation of the PIN code as the symmetric key to encrypt the SM2 private key with the SM4 algorithm, and the SM2 public key is encrypted. The key is not encrypted; then the plaintext of the public key of SM2 and the ciphertext of the encrypted private key of SM2 are stored in the EEPROM module; The encryption card randomly generates an SM4 symmetric key, uses the first 128 bits of the message digest obtained by the first SM3 operation of the PIN code to encrypt the SM4 symmetric key with the SM4 algorithm, and finally encrypts the encrypted SM4 symmetric key. The file is stored in the EEPROM module. 2. The lightweight data protection system based on a national secret algorithm according to claim 1, wherein the host computer software is divided into five panels: a control panel, a login panel, an encryption panel, a decryption panel and a file display panel ,in: The control panel is used to configure the communication port, choose to connect/disconnect the device, and enter/exit the encryption mode; the login panel is used to provide the user login interface and display the login status; the encryption panel is used to select the path of the plaintext file, save the ciphertext The path, the path to save the SM2 public key, and the path to save the SM2 digital signature, and control the start of encryption; the decryption panel is used to select the path of the ciphertext file, the path of the SM2 digital signature, the path of the SM2 public key, and the path of the plaintext file. , and control the start of decryption; the file display panel is used to display the plaintext before encryption/encrypted ciphertext and the ciphertext before decryption/decrypted plaintext. 3. the lightweight data protection system based on national secret algorithm according to claim 1, is characterized in that, the management of key is divided into two levels, the first 128 bits of the message digest that the first SM3 operation of PIN code obtains, It is the first-level key; and the randomly generated SM2 private key and SM4 symmetric key are the second-level key; the first-level key encrypts the second-level key, and then saves the ciphertext of the key When the secondary key needs to be used, the ciphertext of the key must be taken out first and decrypted with the primary key before it can be used. 4. the lightweight data protection system based on national secret algorithm according to claim 1, is characterized in that, the flow process of encryption and decryption and digital signature and verification is: In the encryption card, the plaintext is first encrypted by SM4 to generate the ciphertext, and then the message digest of the ciphertext is generated by the SM3 algorithm, and then the SM2 digital signature is performed on the message digest, and finally the digital signature and the ciphertext are sent to the host computer together; When verifying the signature, first obtain the message digest of the original ciphertext through the SM2 signature verification algorithm for the digital signature, and then obtain the message digest of the received ciphertext through the SM3 algorithm, and then compare the above two message digests, and verify if they are the same. If it succeeds, SM4 decrypts the ciphertext to obtain the plaintext, and sends the plaintext to the upper computer; otherwise, the verification fails, and subsequent decryption is not performed. 5. The lightweight data protection system based on the national secret algorithm according to claim 1, is characterized in that, at the beginning of the operation of the host computer, only the control panel is displayed, and the user must connect the device, register, and log in successfully to perform encryption and decryption; The reset function can be used to clear all account and key data of the encrypted card; among them, registration is required for the first use or the first use after reset. 6 . The lightweight data protection system based on a national secret algorithm according to claim 1 , wherein the security chip adopts the IoT security chip CE2343P7 of Foshan Xinzhu Microelectronics Co., Ltd. 7 . 7 . The lightweight data protection system based on a national secret algorithm according to claim 1 , wherein the embedded firmware program further comprises a board-level support package, and the board-level support package is used to provide an environment for the firmware to run. 8 .

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