CN111814212B - Bus data protection method, device, storage medium and chip - Google Patents

Abstract

The application discloses a bus data protection method and device, a storage medium and a chip, and belongs to the technical field of chip safety. The method comprises the following steps: when the first module is a master module, the second module is a slave module, and the first module performs write operation to the second module, or when the first module is a slave module, the second module is a master module, and the second module performs read operation to the first module, the first module sends the sensitive data to the bus encryption module; the bus encryption module acquires a first random number and sends encrypted data obtained by encrypting the sensitive data according to the first random number to the bus; the bus sends the encrypted data to the bus decryption module; the bus decryption module obtains a second random number, and sensitive data obtained by decrypting the encrypted data according to the second random number are sent to the second module, wherein the second random number is the same as the first random number. The embodiment of the application can ensure the consistency of random numbers, improve the safety and accuracy of data transmission and reduce the overhead of bus bit width.

Description

Bus data protection method, device, storage medium and chip

technical field

The embodiments of the present application relate to the field of chip security, and in particular, to a method, device, storage medium, and chip for protecting bus data.

Background technique

As the core component of the system, the chip plays a pivotal role in major fields such as computers, consumer electronics, network communications, and automotive electronics. In order to improve the security of sensitive data in the chip, the entire process of sensitive data in the chip from generation (one end) to use/consumption (one end) needs to be encrypted and protected. Currently, the more common encryption protection technology is bus encryption technology.

Most of the current chips use a bus to connect the master module and the slave module, thereby realizing the data interconnection of the master and slave modules. In many chips, the bus is a topology that spreads all over the chip, and can physically exist in various parts of the chip. Currently, we can use physical attack methods to monitor the status of internal signals for the weak points of the bus, and it is possible to find the monitor. point, directly stealing sensitive data. In the prior art, random numbers can be added to sensitive data, and mask transmission of random numbers and sensitive data can be performed.

The above bus encryption technology needs to transmit sensitive data and random numbers at the same time, and hackers can monitor the masked sensitive data and masked random numbers at the same time, and then solve the sensitive data through simple operations, resulting in the leakage of sensitive data. In addition, transferring sensitive data and masking random numbers on the bus increases the bit-width overhead of the bus.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a bus data protection method, device, storage medium and chip, which are used to solve the problem of low security and increased bus bit width when simultaneously transmitting masked sensitive data and masked random numbers on the bus cost issue. The technical solution is as follows:

In one aspect, a method for protecting bus data is provided, the method comprising:

When the first module determines that the sensitive data needs to be sent to the second module according to the read operation or the write operation, the first module sends the sensitive data to the bus encryption module;

The bus encryption module receives the sensitive data, obtains the first random number in the first random number generator corresponding to the first module, encrypts the sensitive data according to the first random number, and obtains The encrypted data is sent to the bus;

The bus sends the encrypted data to the bus decryption module;

The bus decryption module receives the encrypted data, obtains the second random number in the second random number generator corresponding to the second module, decrypts the encrypted data according to the second random number, and obtains the obtained data. The sensitive data is sent to the second module, and the second random number and the first random number are the same random number obtained after updating the same true random number for the same number of times;

The second module receives the sensitive data.

In a possible implementation, the method further includes:

After each data transmission is completed, the main module sends a random number update request to the random number consistency bus, and the main module is the module that initiates data transmission in the first module and the second module;

The random number consistency bus controls each first random number generator to update the respective first random number once, and controls each second random number generator to update the respective second random number once;

Wherein, each first random number generator corresponds to a first module, each second random number generator corresponds to a second module, and the updated first random number is the same as the updated second random number.

In one possible implementation,

The controlling each first random number generator to update the respective first random number once includes: for each first random number generator in the first state, the first random number generator updates its own random number generator. The first random number is updated once; for each first random number generator in the second state, the first random number generator records the number of times k to be updated of its own first random number, and in the first random number After the first module corresponding to the number generator completes data transmission, it updates its first random number k times, and sets its own state to the first state, and the second state is the first random number The first module corresponding to the generator is performing data transmission, and other first modules and second modules are set when data transmission is completed, and the k is a positive integer;

The controlling each second random number generator to update the respective second random number once, including: for each second random number generator in the first state, the second random number generator updates its own The second random number is updated once; for each second random number generator in the second state, the second random number generator records the number of times n to be updated of its own second random number, and in the second random number After the second module corresponding to the number generator completes data transmission, it updates its second random number n times, and sets its own state to the first state, and the second state is the second random number The n is a positive integer set when the second module corresponding to the generator is performing data transmission, and other first modules and second modules complete data transmission.

In a possible implementation, the method further includes:

When the bus is in an idle state, the true random number source broadcasts true random numbers to all first random number generators and all second random number generators;

Each first random number generator generates an initial first random number according to the true random number;

Each second random number generator generates an initial second random number according to the true random number;

Wherein, the initial first random number and the initial second random number are the same.

In a possible implementation, it is characterized in that,

The encrypting the sensitive data according to the first random number includes: acquiring, by the bus encryption module, an encryption algorithm corresponding to the sensitive data, and encrypting the sensitive data according to the first random number and the encryption algorithm. data is encrypted;

The decrypting the encrypted data according to the second random number includes: obtaining, by the bus decryption module, a decryption algorithm corresponding to the encrypted data, and decrypting the encrypted data according to the second random number and the decryption algorithm. The data is decrypted, and the decryption algorithm corresponds to the encryption algorithm.

In one possible implementation,

The bus encryption module obtains the encryption algorithm corresponding to the sensitive data, including: the bus encryption module obtains the address information of the slave module, and searches for the encryption algorithm corresponding to the address information in the first correspondence, the first The mapping between different address information and different encryption algorithms is stored in the corresponding relationship;

The bus decryption module obtaining the decryption algorithm corresponding to the encrypted data includes: the bus decryption module obtains the address information of the slave module, and searches for the decryption algorithm corresponding to the address information in the second correspondence relationship, the The second correspondence stores mappings between different address information and different decryption algorithms;

Wherein, the slave module is a module used for data storage or data operation in the first module and the second module.

In one possible implementation,

The bus encryption module obtains the encryption algorithm corresponding to the sensitive data, including: the bus encryption module obtains the control signal sent by the bus, and searches for the encryption algorithm corresponding to the control signal in the third correspondence, the third The mapping between different control signals and different encryption algorithms is stored in the corresponding relationship;

Obtaining, by the bus decryption module, a decryption algorithm corresponding to the encrypted data includes: the bus decryption module obtains the control signal sent by the bus, and searches for a decryption algorithm corresponding to the control signal in a fourth correspondence relationship, the The fourth correspondence relationship stores mappings between different control signals and different decryption algorithms.

In one aspect, a device for protecting bus data is provided, the device comprising:

a sending module, configured to send the sensitive data to the bus encryption module through the first module when the first module determines that the sensitive data needs to be sent to the second module according to the read operation or the write operation;

an encryption module, configured to receive the sensitive data through the bus encryption module, and obtain a first random number in a first random number generator corresponding to the first module, and perform the sensitive data according to the first random number The data is encrypted, and the obtained encrypted data is sent to the bus;

a transmission module, configured to send the encrypted data to the bus decryption module through the bus;

A decryption module, configured to receive the encrypted data through the bus decryption module, obtain a second random number in the second random number generator corresponding to the second module, and perform the encryption on the encrypted data according to the second random number Decrypt, and send the obtained sensitive data to the second module, where the second random number and the first random number are the same random number obtained after updating the same true random number for the same number of times;

A receiving module, configured to receive the sensitive data through the second module.

In one aspect, a computer-readable storage medium is provided, wherein the storage medium stores at least one instruction, at least one piece of program, code set or instruction set, the at least one instruction, the at least one piece of program, the code set Or the instruction set is loaded and executed by the processor to implement the bus data protection method as described above.

In one aspect, a chip is provided, the chip includes a processor and a memory, the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the above-mentioned method for protecting bus data .

The beneficial effects of the technical solutions provided by the embodiments of the present application include at least:

When the first module determines that it needs to send sensitive data to the second module according to the read operation or the write operation, it first sends the sensitive data to the bus encryption module through the first module, then receives the sensitive data through the bus encryption module, and obtains the corresponding data of the first module. The first random number in the first random number generator, encrypts the sensitive data according to the first random number, sends the obtained encrypted data to the bus, sends the encrypted data to the bus decryption module by the bus, and finally sends the encrypted data to the bus decryption module through the bus decryption module. Receive the encrypted data, and obtain the second random number in the second random number generator corresponding to the second module, because the second random number and the first random number are the same random number obtained by updating the same true random number for the same number of times. Therefore, the bus decryption module can decrypt the encrypted data according to the second random number, and send the obtained sensitive data to the second module, thereby completing a data transmission. In this embodiment, only the encrypted data needs to be transmitted in the bus, and the first random number does not need to be transmitted. In this way, even if the hacker can monitor the encrypted data, the encrypted data cannot be decrypted because the second random number cannot be obtained. Thus, the security of data transmission is improved. In addition, not needing to transmit the first random number on the bus also reduces the overhead of the bus bit width.

Since the structures of the first random number generator and the second random number generator are the same, and the random seeds received by the first random number generator and the second random number generator are the same, the first random number generator and the second random number generator The generator is updated synchronously according to the random seed, so the first random number obtained by the first random number generator after each self-operation update and the second random number obtained by the second random number generator after each self-operation update are the same , so that sensitive data can be correctly encrypted and decrypted. In addition, after each data transmission is completed, the first random numbers in all the first random number generators and the second random numbers in all the second random number generators need to be updated, and all the first random numbers and The second random number is the same. That is, the first random number and the second random number used in different data transmissions are different, while the first random number and the second random number used in the same data transmission are the same.

The random number generator adopts the true random source to provide the true random entropy source and the pseudo-random generating unit in the form of mixed random number generation. The true random source continuously broadcasts and sends the true random number to the pseudo-random number generator as a random seed, and the random number generator receives it. When the true random source seed is added to the pseudo-random number generating unit, a new random number is generated. After each data transmission, the random number generator performs a pseudo-random unit update. Since the input and update of the random number generators corresponding to the master module and the slave module are consistent, the value of the random number can ensure the consistency, thereby ensuring the unpredictability of the random number and improving the security of data transmission.

When multiple first modules are allowed to send sensitive data to multiple second modules at the same time, the above random number update method can still be used to update the random number, so that the random numbers used for each data encryption and decryption are different, so as to ensure The security of data transmission is ensured; and the first random number and the second random number used in the encryption and decryption of the same data are the same, thus ensuring that they can be correctly encrypted and decrypted.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is a method flowchart of a method for protecting bus data provided by an embodiment of the present application;

2 is a schematic structural diagram of a chip that allows one module to transmit data at the same time according to some exemplary embodiments;

3 is a schematic structural diagram of a chip that allows multiple modules to transmit data at the same time, according to some exemplary embodiments;

FIG. 4 is a schematic structural diagram of an example of a chip according to some exemplary embodiments;

5 is a schematic diagram of original data, random number state and bus encryption result provided by an embodiment of the present application;

FIG. 6 is a structural block diagram of an apparatus for protecting bus data provided by another embodiment of the present application.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

Please refer to FIG. 1 , which shows a method flowchart of a method for protecting bus data provided by an embodiment of the present application, and the method for protecting bus data can be applied to a chip. The protection method of the bus data may include:

Step 101, when the first module determines that it needs to send the sensitive data to the second module according to the read operation or the write operation, the first module sends the sensitive data to the bus encryption module.

The modules used for data transmission in this embodiment include a master module and a slave module. The main module is a module for initiating data transmission. For example, the main module may be a CPU (Central Processing Unit, central processing unit), a DMA (Direct Memory Access, direct memory access), and so on. A slave module is a module for data storage or data operation, or a slave module can be a peripheral. For example, the slave module used for data storage may be ROM (Read-Only Memory), SRAM (Static Random-Access Memory, static random access memory), etc.; the slave module used for data operation may be It is the operation Engine, and the peripherals can be Peripheral and so on.

If the slave module is used for data storage, one application scenario is that the master module writes sensitive data to the slave module. At this time, the first module is the master module, and the second module is the slave module; another application scenario is that the master module is slave Sensitive data is read from the module. At this time, the first module is the slave module and the second module is the master module.

If the slave module is used for data operation, the master module needs to write sensitive data to the slave module. At this time, the first module is the master module, and the second module is the slave module; after obtaining the operation result from the slave module, the master module also needs to obtain the operation result from the slave module. The operation result is read from the module. At this time, the first module is the slave module, and the second module is the master module.

If the slave module is a peripheral device, one application scenario is that the master module sends data to the slave module, and another application scenario is that the slave module sends data to the master module. Usually, the data transmitted between the master module and the slave module is not sensitive data, so the data can be transmitted in clear text on the bus without transmitting encrypted data.

Regardless of whether the first module is a master module or a slave module, as long as the first module needs to send sensitive data to the second module, the sensitive data will be sent to the bus encryption module.

Step 102, the bus encryption module receives the sensitive data, obtains a first random number in the first random number generator corresponding to the first module, encrypts the sensitive data according to the first random number, and sends the obtained encrypted data to the bus.

The chip in this embodiment may include multiple first modules and multiple second modules. When only one first module is allowed to send sensitive data to one second module at the same time, if the first module is the master module and the second module is the slave module, a bus encryption module is set between the first module and the bus, and the second module is a slave module. A bus decryption module is set between the second module and the bus; if the first module is a slave module and the second module is a master module, a bus decryption module is set between the first module and the bus, and a bus decryption module is set between the second module and the bus. A bus encryption module is provided. For convenience of description, in this embodiment, a bus encryption module and a bus decryption module between the first module and the bus are collectively referred to as a bus encryption and decryption module, and a bus encryption module and a bus between the second module and the bus are referred to as The decryption module is collectively referred to as a bus encryption and decryption module, and each bus encryption and decryption module is provided with a random number generator, each random number generator is connected to a true random source, and the true random source includes a random entropy source, Used to broadcast a true random number to the random number generator as a random seed.

Please refer to FIG. 2. In FIG. 2, the chip includes two main modules and four slave modules as an example. The two main modules are connected to the bus through a bus encryption and decryption module, and the three slave modules are also encrypted and decrypted through a bus. The modules are connected to the bus so that the three slave modules and the two master modules can transmit encrypted data on the bus. The remaining one slave module is directly connected to the bus, and the slave module and the two master modules can transmit plaintext data on the bus. It should be noted that, an encryption/decryption module may also be set in the slave module, which is not limited in this embodiment.

When multiple first modules are allowed to send sensitive data to multiple second modules at the same time, that is, when one first module sends sensitive data to one second module, another first module can send sensitive data to another second module At this time, a bus encryption and decryption module and a random number generator can be allocated to each first module, and a bus encryption and decryption module and a random number generator can be allocated to each second module. In this way, each first module It is connected to the bus through a corresponding bus encryption and decryption module, and is connected to the random number consistency bus through a corresponding random number generator; each second module is connected to the bus through a corresponding bus encryption and decryption module, and through a corresponding one The random number generator is connected to the random number consistency bus, and the random number consistency bus is connected to a true random source, which includes a random entropy source for broadcasting to the random number generator through the random number consistency bus True random numbers as random seeds.

Please refer to FIG. 3. In FIG. 3, the chip includes two main modules and four slave modules as an example. Each main module corresponds to a bus encryption and decryption module and a random number generator, and each main module passes through A corresponding bus encryption and decryption module is connected to the bus, and is connected to the random number consistency bus through a corresponding random number generator. Each of the three slave modules corresponds to a bus encryption and decryption module and a random number generator, and each slave module is connected to the bus through a corresponding bus encryption and decryption module, and is connected to the bus through a corresponding random number generator. The random number consistency bus is connected. In this way, the three slave modules and the two master modules can transmit encrypted data on the bus. The remaining one slave module is directly connected to the bus, and the slave module and the two master modules can transmit plaintext data on the bus. It should be noted that, an encryption/decryption module may also be set in the slave module, which is not limited in this embodiment.

Please refer to Figure 4. In Figure 4, a main module is a CPU, a main module is a DMA, a slave module is a ROM, a slave module is a SRAM, a slave module is an operation engine, and a slave module is a peripheral (Peripheral). The bus is AHB32bit bus.

In this embodiment, after receiving the sensitive data, the bus encryption module can read the first random number from the first random number generator, and then encrypt the sensitive data according to the first random number to obtain encrypted data, and finally This encrypted data is sent to the bus. The bus encryption module mentioned here is the module involved in the encryption function in the bus encryption and decryption module corresponding to the first module. The first random number may be a random number obtained by the first random number generator updating the received true random number as a random seed.

Among them, high-security encryption, standard security encryption and non-encryption methods can be used to transmit data according to security requirements, that is, different encryption algorithms can be used to encrypt sensitive data. At this time, the sensitive data is encrypted according to the first random number, including: The bus encryption module obtains an encryption algorithm corresponding to the sensitive data, and encrypts the sensitive data according to the first random number and the encryption algorithm.

In the first encryption method, the bus encryption module obtains the encryption algorithm corresponding to the sensitive data, including: the bus encryption module obtains the address information of the slave module, searches for the encryption algorithm corresponding to the address information in the first correspondence, the first correspondence There are mappings between different address information and different encryption algorithms stored in .

In the second encryption method, the bus encryption module obtains the encryption algorithm corresponding to the sensitive data, including: the bus encryption module obtains the control signal sent by the bus, searches for the encryption algorithm corresponding to the control signal in the third correspondence, and the third correspondence The mappings between different control signals and different encryption algorithms are stored in .

For example, the AHB bus uses the HUSER signal as the control signal, and the AXI bus uses the AxUSER signal as the control signal.

Optionally, the main module can also send other data such as the address information of the module and the ID of the main module to the bus encryption module. The bus encryption module can only encrypt sensitive data, but not other data, and encrypt the encrypted data and other data. sent to the bus.

Step 103, the bus sends the encrypted data to the bus decryption module.

In this embodiment, in addition to obtaining encrypted data, the bus may also obtain other data such as address information of the slave module, ID of the master module, and the like. The above other data may be sent to the bus by the bus encryption module, or may be sent to the bus by the main module, which is not limited in this embodiment.

The bus determines a bus decryption module corresponding to the second module according to the address information, and sends the encrypted data to the bus decryption module. The bus decryption module mentioned here is the module involved in the decryption function in the bus encryption and decryption module corresponding to the second module.

Step 104, the bus decryption module receives the encrypted data, obtains the second random number in the second random number generator corresponding to the second module, decrypts the encrypted data according to the second random number, and sends the obtained sensitive data to the second module , the second random number and the first random number are the same random numbers obtained by updating the same true random number for the same number of times.

In this embodiment, after receiving the encrypted data, the bus decryption module can read the second random number from the second random number generator, and then decrypt the encrypted data according to the second random number to obtain sensitive data, and finally This sensitive data is sent to the second module. The second random number may be a random number obtained by the second random number generator updating the received true random number as a random seed. The second random number and the first random number are updated based on the same true random number, and the number of times of updating the second random number and the first random number is the same, so that the second random number can be guaranteed to be the same as the first random number.

Wherein, decrypting the encrypted data according to the second random number may include: the bus decryption module obtains a decryption algorithm corresponding to the encrypted data, decrypts the encrypted data according to the second random number and the decryption algorithm, and the decryption algorithm corresponds to the encryption algorithm.

Corresponding to the first encryption method, the bus decryption module obtains the decryption algorithm corresponding to the encrypted data, which may include: the bus decryption module obtains the address information of the slave module, and searches for the decryption algorithm corresponding to the address information in the second correspondence relationship. A mapping between different address information and different decryption algorithms is stored in the relationship.

Corresponding to the second decryption method, the bus decryption module obtains the decryption algorithm corresponding to the encrypted data, which may include: the bus decryption module obtains the control signal sent by the bus, searches for the decryption algorithm corresponding to the control signal in the fourth correspondence, and the fourth correspondence The relationship stores mappings between different control signals and different decryption algorithms.

Taking Figure 3 as an example, when the master module 1 or 2 sends sensitive data to the slave module 1 or 2, the sensitive data is encrypted by the algorithm A in the bus encryption and decryption module, and the encrypted data is transmitted on the bus (Bus Matrix), using bus encryption and decryption. The algorithm A in the module decrypts the encrypted data. When the master module 1 or 2 sends sensitive data to the slave module 3, the sensitive data is encrypted by the algorithm B in the bus encryption and decryption module, the encrypted data is transmitted on the bus, and the encrypted data is decrypted by the algorithm B in the bus encryption and decryption module. When the master module 1 or 2 sends data to the slave module 4, no encryption and decryption operations are performed on the data.

It should be noted that the structures of the first random number generator and the second random number generator are the same, and the random seeds received by the first random number generator and the second random number generator are the same. The second random number generator is updated synchronously according to the random seed. Therefore, the first random number obtained by the first random number generator after each self-operation update and the second random number generator obtained after each self-operation update by the second random number generator The random numbers are the same, which ensures that sensitive data can be encrypted and decrypted correctly. In this way, only the encrypted data needs to be transmitted on the bus, and the first random number involved in encryption and the second random number involved in decryption are not transmitted on the bus, which reduces the transmission overhead and logic scale of the bus, and also increases the security of the bus.

Step 105, the second module receives sensitive data.

In this embodiment, after each data transmission is completed, the first random numbers in all the first random number generators and the second random numbers in all the second random number generators need to be updated, and all the first random number generators need to be updated. The random number and the second random number are the same. That is, the first random number and the second random number used in different data transmissions are different, while the first random number and the second random number used in the same data transmission are the same.

If only one first module is allowed to send sensitive data to one second module at the same time, after each data transmission is completed, the first random number generator and the second random number generator need to be controlled to update random numbers. If multiple first modules are allowed to send sensitive data to multiple second modules at the same time, the random number update can be coordinated through the random number consistency bus, and specifically, the random number update can be performed through steps 106-107.

Step 106, after each data transmission is completed, the main module sends a random number update request to the random number consistency bus, where the main module is the module that initiates data transmission in the first module and the second module.

When the read operation or the write operation is a single transfer operation, only one data transfer needs to be performed for one data transfer. When a read operation or a write operation is a burst transfer operation, one data transfer needs to transfer multiple data. Among them, the burst transfer operation is widely used in the bus data transfer of the chip.

Step 107, the random number consistency bus controls each first random number generator to update the respective first random number once, and controls each second random number generator to update the respective second random number once.

Wherein, each first random number generator corresponds to a first module, each second random number generator corresponds to a second module, and the updated first random number is the same as the updated second random number.

Specifically, controlling each first random number generator to update the respective first random number once, including: for each first random number generator in the first state, the first random number generator updates its own first random number generator. A random number is updated once; for each first random number generator in the second state, the first random number generator records the number of times k to be updated of its own first random number, and the first random number generator corresponds to After the first module completes data transmission, it updates its first random number k times, and sets its own state to the first state, and the second state is that the first module corresponding to the first random number generator is performing data transmission. , and is set when other first modules and second modules complete data transmission, and k is a positive integer. Controlling each second random number generator to update the respective second random numbers once may include: for each second random number generator in the first state, the second random number generator updates its own second random number generator. The number is updated once; for each second random number generator in the second state, the second random number generator records the number of times n to be updated of its own second random number, and in the second random number generator corresponding to the second random number generator After the module completes data transmission, it updates its own second random number n times, and sets its own state to the first state. The second state is that the second module corresponding to the second random number generator is performing data transmission, and It is set when the other first modules and second modules complete data transmission, and n is a positive integer.

When the data transmission from a first module to a second module is in progress, and the data transmission from another first module to another second module ends, the first random number corresponding to the first module in the data transmission is generated. Both the state of the second random number generator corresponding to the second module and the second module need to be set to dirty (Dirty) (ie the second state), and need to record how many times it needs to be updated (ie the number of times to be updated n) to catch up with other random numbers The update of the random numbers in the generator makes the random numbers in all the random number generators consistent. When the data transmission corresponding to the first random number generator and the second random number generator marked as dirty is completed, the random number update needs to be performed. After the update is completed, the status of the first random number generator and the second random number generator becomes Clean (ie, the first state).

It should be noted that when the state of the first random number generator corresponding to a first module is dirty, the first module cannot perform encrypted data transmission until the state of the first random number generator becomes clean; When the state of the second random number generator corresponding to the second module is dirty, the second module cannot perform encrypted data transmission until the state of the second random number generator becomes clean. In addition, when a first module and a second module are in the process of data transmission, another first module wants to perform data transmission with the second module, it must wait until the current data transmission ends and the random number update is completed before it can start. the next data transfer.

In this embodiment, the random number consistency bus can also acquire the transmission status of each main module. If there is at least one main module in the process of data transmission, the transmission status of each main module will continue to be acquired; if all main modules are not performing data transmission Transmission, that is, the bus is in an idle state, can trigger the update of the true random number. That is, when the bus is in an idle state, the true random number source broadcasts true random numbers to all first random number generators and all second random number generators; each first random number generator generates an initial random number according to the true random number. a first random number; each second random number generator generates an initial second random number according to the true random number; wherein, the initial first random number and the initial second random number are the same.

The random number generator in this embodiment adopts a true random source to provide a mixed random number generation form of a true random entropy source and a pseudo-random generating unit, and the true random source continuously broadcasts and sends the true random number to the pseudo-random number generator as a random seed, The random number generator receives the true random source seed and adds it to the pseudo-random number generating unit to generate a new random number. After each data transmission, the random number generator performs a pseudo-random unit update. Since the input and update of the random number generators corresponding to the master module and the slave module are consistent, the value of the random number can ensure consistency. The pseudo-random number unit may adopt the structure of a linear feedback shift register (Linear Feedback Shift Register, LFSR).

To sum up, in the method for protecting bus data provided by the embodiments of the present application, when the first module determines that it needs to send sensitive data to the second module according to the read operation or the write operation, the first module sends the sensitive data to the bus encryption first. module, and then receive the sensitive data through the bus encryption module, and obtain the first random number in the first random number generator corresponding to the first module, encrypt the sensitive data according to the first random number, and send the obtained encrypted data to the bus , the encrypted data is sent to the bus decryption module by the bus, and finally the encrypted data is received through the bus decryption module, and the second random number in the second random number generator corresponding to the second module is obtained. It is the same random number obtained by updating the same true random number for the same number of times. Therefore, the bus decryption module can decrypt the encrypted data according to the second random number, and send the obtained sensitive data to the second module to complete the data. transmission. In this embodiment, only the encrypted data needs to be transmitted in the bus, and the first random number does not need to be transmitted. In this way, even if the hacker can monitor the encrypted data, the encrypted data cannot be decrypted because the second random number cannot be obtained. Thus, the security of data transmission is improved. In addition, not needing to transmit the first random number on the bus also reduces the overhead of the bus bit width.

Since the structures of the first random number generator and the second random number generator are the same, and the random seeds received by the first random number generator and the second random number generator are the same, the first random number generator and the second random number generator The generator is updated synchronously according to the random seed, so the first random number obtained by the first random number generator after each self-operation update and the second random number obtained by the second random number generator after each self-operation update are the same , so that sensitive data can be correctly encrypted and decrypted. In addition, after each data transmission is completed, the first random numbers in all the first random number generators and the second random numbers in all the second random number generators need to be updated, and all the first random numbers and The second random number is the same. That is, the first random number and the second random number used in different data transmissions are different, while the first random number and the second random number used in the same data transmission are the same.

The random number generator adopts the true random source to provide the true random entropy source and the pseudo-random generating unit in the form of mixed random number generation. The true random source continuously broadcasts and sends the true random number to the pseudo-random number generator as a random seed, and the random number generator receives it. When the true random source seed is added to the pseudo-random number generating unit, a new random number is generated. After each data transmission, the random number generator performs a pseudo-random unit update. Since the input and update of the random number generators corresponding to the master module and the slave module are consistent, the value of the random number can ensure the consistency, thereby ensuring the unpredictability of the random number and improving the security of data transmission.

Since only one first module can be allowed to send sensitive data to one second module at the same time, or multiple first modules can be allowed to send sensitive data to multiple second modules at the same time, the transmission mode of sensitive data can be expanded. , also expands the structure of the chip.

When multiple first modules are allowed to send sensitive data to multiple second modules at the same time, the above random number update method can still be used to update the random number, so that the random numbers used for each data encryption and decryption are different, so as to ensure The security of data transmission is ensured; and the first random number and the second random number used in the encryption and decryption of the same data are the same, thus ensuring that they can be correctly encrypted and decrypted.

The following describes the data transmission process with an example.

Assume that the main modules are CPU and DMA, and the slave modules are ROM, SRAM, computing engine, and peripherals, respectively. ROM and SRAM contain encryption and decryption modules. Engine module does not include encryption and decryption modules. The peripherals do not perform data encryption and decryption operations. The selection of the encryption and decryption algorithms in the encryption and decryption module is determined according to the division of the address information of the slave modules.

The random number generator of the master-slave module adopts the LFSR structure. An LFSR structure with a length of m has a maximum internal state of 2m. Since the "0" state is fully closed, its period is at most 2m−1. When the polynomial formed by adding 1 to the tap sequence is a primitive polynomial, the LFSR structure has a maximum period of 2m−1. The generator polynomial in this example is: x ³¹ + x ³ +x ² + x + 1, then the feedback function uses the bits of taps 30, 3, 2, 1, and 0 for XOR output.

The encryption algorithm in this example uses sensitive data, random numbers and addresses to be XORed respectively. Based on the XOR feature, the decryption operation is the same as the encryption algorithm.

In the process of chip initialization, the true random source sends true random numbers to the random number generators corresponding to each master-slave module to keep the random numbers in each random number generator in a consistent state. Here, it is assumed that the initial random number is 0xbae7eb8b.

1. Suppose the CPU starts a data transfer with the ROM first. The data transfer needs to be encrypted. After the transfer is completed, the random number generator is updated, and the random number is updated to 0x75cfd717;

2. If the CPU starts the next data transfer with the ROM, at the same time, the DMA starts a burst (Burst) data transfer (read operation) to the SRAM. When the data transfer from the CPU to the ROM is completed, the data transfer from the DMA to the SRAM is still in progress.

3. The CPU starts a data transfer to the computing engine. At this time, the DMA data transfer to the SRAM continues. Since the data transfer is not delayed, the random number update request can be sent to all random numbers through the random number consistency bus. in the generator.

4. When the bus is in an idle state, the random number seed can be broadcast, so that all random number generators can generate a new initial random number 0x73f5c5c9;

5. DMA continues to perform burst (Burst) data transfer (write operation) to SRAM;

6. The CPU starts a data transfer to the computing engine. Since the computing of the computing engine has never ended, and every time the DMA data transfer to the SRAM occurs, the DMA will send a random number update request to the random number consistency bus, and at the same time its own The random numbers in the random number generator are also updated accordingly. During the data transmission process, the CPU and the computing engine receive a random number update request from the random number consistency bus. It is necessary to set the state of the random number generator corresponding to the CPU and the computing engine to dirty, and determine the data transfer between the DMA and the SRAM. During this period, 4 random number updates occurred. After the CPU completes the data transmission with the computing engine, the random number needs to be updated 4 times through the corresponding random number generators, and then the random number generator corresponding to the CPU and computing engine can be updated. The status is set to clean.

7. The CPU starts a data transmission to the peripheral. Since the peripheral is in a safe area that does not require encryption, the data is not encrypted and the random number is not updated.

Please refer to the original data, random number status and bus encryption result of each data transmission shown in Figure 5.

Please refer to FIG. 6 , which shows a structural block diagram of an apparatus for protecting bus data provided by an embodiment of the present application. The apparatus for protecting bus data can be applied to a chip. The protection device for bus data may include:

The sending module 610 is configured to send the sensitive data to the bus encryption module through the first module when the first module determines that it needs to send the sensitive data to the second module according to the read operation or the write operation;

The encryption module 620 is configured to receive the sensitive data through the bus encryption module, obtain the first random number in the first random number generator corresponding to the first module, encrypt the sensitive data according to the first random number, and encrypt the obtained encrypted data sent to the bus;

a transmission module 630, configured to send the encrypted data to the bus decryption module through the bus;

The decryption module 640 is configured to receive the encrypted data through the bus decryption module, obtain the second random number in the second random number generator corresponding to the second module, decrypt the encrypted data according to the second random number, and send the obtained sensitive data For the second module, the second random number and the first random number are the same random number obtained by updating the same true random number for the same number of times;

The receiving module 650 is used for receiving sensitive data through the second module.

In an optional embodiment, the apparatus further includes an update module for:

After each data transmission is completed, the main module sends a random number update request to the random number consistency bus, and the main module is the module that initiates data transmission in the first module and the second module;

The random number consistency bus controls each first random number generator to update the respective first random number once, and controls each second random number generator to update the respective second random number once;

Wherein, each first random number generator corresponds to a first module, each second random number generator corresponds to a second module, and the updated first random number is the same as the updated second random number.

In an optional embodiment, the update module is also used for:

For each first random number generator in the first state, the first random number generator updates its own first random number once; for each first random number generator in the second state, the first random number generator The number generator records the number of times k of its own first random number to be updated, and after the first module corresponding to the first random number generator completes data transmission, it updates its own first random number k times, and updates its own state. Set to the first state, and the second state is set when the first module corresponding to the first random number generator is performing data transmission, and other first modules and second modules complete data transmission, and k is a positive integer;

For each second random number generator in the first state, the second random number generator updates its own second random number once; for each second random number generator in the second state, the second random number generator The number generator records the number of times n to be updated of its own second random number, and after the second module corresponding to the second random number generator completes data transmission, it updates its own second random number n times, and updates its own state. Set to the first state, the second state is set when the second module corresponding to the second random number generator is performing data transmission, and other first modules and second modules complete data transmission, and n is a positive integer.

In an optional embodiment, the update module is also used for:

When the bus is in an idle state, the true random number source broadcasts true random numbers to all first random number generators and all second random number generators;

Each first random number generator generates an initial first random number according to the true random number;

each second random number generator generates an initial second random number according to the true random number;

Wherein, the initial first random number and the initial second random number are the same.

In an optional embodiment, the encryption module 620 is further configured to obtain an encryption algorithm corresponding to the sensitive data through the bus encryption module, and encrypt the sensitive data according to the first random number and the encryption algorithm;

The decryption module 640 is further configured to obtain a decryption algorithm corresponding to the encrypted data through the bus decryption module, and decrypt the encrypted data according to the second random number and the decryption algorithm, and the decryption algorithm corresponds to the encryption algorithm.

In an optional embodiment, the encryption module 620 is further configured to obtain the address information of the slave module through the bus encryption module, search for the encryption algorithm corresponding to the address information in the first correspondence, and store different encryption algorithms in the first correspondence. The mapping between the address information and different encryption algorithms;

The decryption module 640 is also used to obtain the address information of the slave module through the bus decryption module, and search for the decryption algorithm corresponding to the address information in the second correspondence relationship, and the second correspondence relationship stores the difference between different address information and different decryption algorithms. mapping between;

Wherein, the slave module is a module used for data storage or data operation in the first module and the second module.

In an optional embodiment, the encryption module 620 is further configured to obtain the control signal sent by the bus through the bus encryption module, search for the encryption algorithm corresponding to the control signal in the third correspondence, and store the different encryption algorithms in the third correspondence. The mapping between the control signal and different encryption algorithms;

The decryption module 640 is further configured to obtain the control signal sent by the bus through the bus decryption module, search for the decryption algorithm corresponding to the control signal in the fourth correspondence, and store the difference between different control signals and different decryption algorithms in the fourth correspondence. mapping between.

To sum up, in the bus data protection device provided by the embodiment of the present application, when the first module determines that it needs to send sensitive data to the second module according to the read operation or the write operation, the first module sends the sensitive data to the bus encryption first. module, and then receive the sensitive data through the bus encryption module, and obtain the first random number in the first random number generator corresponding to the first module, encrypt the sensitive data according to the first random number, and send the obtained encrypted data to the bus , the encrypted data is sent to the bus decryption module by the bus, and finally the encrypted data is received through the bus decryption module, and the second random number in the second random number generator corresponding to the second module is obtained. It is the same random number obtained by updating the same true random number for the same number of times. Therefore, the bus decryption module can decrypt the encrypted data according to the second random number, and send the obtained sensitive data to the second module to complete the data. transmission. In this embodiment, only the encrypted data needs to be transmitted in the bus, and the first random number does not need to be transmitted. In this way, even if the hacker can monitor the encrypted data, the encrypted data cannot be decrypted because the second random number cannot be obtained. Thus, the security of data transmission is improved. In addition, not needing to transmit the first random number on the bus also reduces the overhead of the bus bit width.

Since the structures of the first random number generator and the second random number generator are the same, and the random seeds received by the first random number generator and the second random number generator are the same, the first random number generator and the second random number generator The generator is updated synchronously according to the random seed, so the first random number obtained by the first random number generator after each self-operation update and the second random number obtained by the second random number generator after each self-operation update are the same , so that sensitive data can be correctly encrypted and decrypted. In addition, after each data transmission is completed, the first random numbers in all the first random number generators and the second random numbers in all the second random number generators need to be updated, and all the first random numbers and The second random number is the same. That is, the first random number and the second random number used in different data transmissions are different, while the first random number and the second random number used in the same data transmission are the same.

The random number generator adopts the true random source to provide the true random entropy source and the pseudo-random generating unit in the form of mixed random number generation. The true random source continuously broadcasts and sends the true random number to the pseudo-random number generator as a random seed, and the random number generator receives it. When the true random source seed is added to the pseudo-random number generating unit, a new random number is generated. After each data transmission, the random number generator performs a pseudo-random unit update. Since the input and update of the random number generators corresponding to the master module and the slave module are consistent, the value of the random number can ensure the consistency, thereby ensuring the unpredictability of the random number and improving the security of data transmission.

Since only one first module can be allowed to send sensitive data to one second module at the same time, or multiple first modules can be allowed to send sensitive data to multiple second modules at the same time, the transmission mode of sensitive data can be expanded. , also expands the structure of the chip.

When multiple first modules are allowed to send sensitive data to multiple second modules at the same time, the above random number update method can still be used to update the random number, so that the random numbers used for each data encryption and decryption are different, so as to ensure The security of data transmission is ensured; and the first random number and the second random number used in the encryption and decryption of the same data are the same, thus ensuring that they can be correctly encrypted and decrypted.

An embodiment of the present application provides a computer-readable storage medium, in which at least one instruction, at least one piece of program, code set or instruction set is stored, the at least one instruction, the at least one piece of program, the The code set or instruction set is loaded and executed by the processor to implement the bus data protection method as described above.

An embodiment of the present application provides a chip, the chip includes a processor and a memory, the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the above-mentioned bus data transfer method of protection.

It should be noted that: when the bus data protection device provided in the above embodiment protects the bus data, only the division of the above functional modules is used as an example for illustration. In practical applications, the above functions can be allocated by different The function module is completed, that is, the internal structure of the bus data protection device is divided into different function modules, so as to complete all or part of the functions described above. In addition, the bus data protection device and the bus data protection method embodiment provided by the above embodiments belong to the same concept, and the specific implementation process thereof is detailed in the method embodiment, which will not be repeated here.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above embodiments can be completed by hardware, or can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. The storage medium mentioned may be a read-only memory, a magnetic disk or an optical disk, etc.

The above is not intended to limit the embodiments of the present application, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included within the protection scope of the embodiments of the present application.

Claims (8)

1. A method for protecting bus data, the method comprising:

when a first module determines that sensitive data needs to be sent to a second module according to read operation or write operation, the first module sends the sensitive data to a bus encryption module;

the bus encryption module receives the sensitive data, acquires a first random number in a first random number generator corresponding to the first module, encrypts the sensitive data according to the first random number, and sends the acquired encrypted data to a bus;

the bus sends the encrypted data to a bus decryption module;

the bus decryption module receives the encrypted data, acquires a second random number in a second random number generator corresponding to the second module, decrypts the encrypted data according to the second random number, and sends the acquired sensitive data to the second module, wherein the second random number and the first random number are the same random numbers acquired by updating the same true random number for the same times;

the second module receives the sensitive data;

wherein the method further comprises:

after each data transmission is finished, a main module sends a random number updating request to a random number consistency bus, wherein the main module is a module initiating data transmission in the first module and the second module;

the random number consistency bus controls each first random number generator to update the first random number of the first random number generator once, and controls each second random number generator to update the second random number of the second random number generator once;

each first random number generator corresponds to one first module, each second random number generator corresponds to one second module, and the updated first random number is the same as the updated second random number;

the controlling each first random number generator to update the respective first random number once comprises: for each first random number generator in the first state, the first random number generator updates the first random number of the first random number generator once; for each first random number generator in the second state, the first random number generator records the number k of times to be updated of the own first random number, after the first module corresponding to the first random number generator completes data transmission, the own first random number is updated for k times, and the own state is set to be the first state, wherein k is a positive integer;

the controlling each second random number generator to update the respective second random number once includes: for each second random number generator in the first state, the second random number generator updates the second random number of the second random number generator once; for each second random number generator in the second state, the second random number generator records the number n of times to be updated of the second random number generator, after the second module corresponding to the second random number generator completes data transmission, the second random number of the second random number generator is updated for n times, the state of the second random number generator is set to be the first state, and n is a positive integer;

the second state is set for the first random number generator and the second random number generator when the first module corresponding to the first random number generator is transmitting data with the second module corresponding to the second random number generator and the data transmission of the other first module to the other second module is completed;

the first state is set for the first random number generator and the second random number generator after the first random number generator and the second random number generator in the second state complete random number updating.

2. The method of claim 1, further comprising:

when the bus is in an idle state, the true random source broadcasts true random numbers to all the first random number generators and all the second random number generators;

each first random number generator generates an initial first random number according to the true random number;

each second random number generator generates an initial second random number according to the true random number;

wherein the initial first random number and the initial second random number are the same.

3. The method according to claim 1 or 2,

the encrypting the sensitive data according to the first random number includes: the bus encryption module acquires an encryption algorithm corresponding to the sensitive data and encrypts the sensitive data according to the first random number and the encryption algorithm;

the decrypting the encrypted data according to the second random number includes: and the bus decryption module acquires a decryption algorithm corresponding to the encrypted data, and decrypts the encrypted data according to the second random number and the decryption algorithm, wherein the decryption algorithm corresponds to the encryption algorithm.

4. The method of claim 3,

the bus encryption module acquires an encryption algorithm corresponding to the sensitive data, and the encryption algorithm comprises the following steps: the bus encryption module acquires address information of a slave module, and searches an encryption algorithm corresponding to the address information in a first corresponding relation, wherein mapping between different address information and different encryption algorithms is stored in the first corresponding relation;

the bus decryption module obtains a decryption algorithm corresponding to the encrypted data, and the decryption algorithm comprises the following steps: the bus decryption module acquires address information of the slave module, and searches a decryption algorithm corresponding to the address information in a second corresponding relation, wherein the second corresponding relation stores mapping between different address information and different decryption algorithms;

the slave module is a module, which is used for performing data storage or data operation in response to data transmission initiated by the master module, in the first module and the second module.

5. The method of claim 3,

the bus encryption module acquires an encryption algorithm corresponding to the sensitive data, and the encryption algorithm comprises the following steps: the bus encryption module acquires a control signal sent by a bus, and searches an encryption algorithm corresponding to the control signal in a third corresponding relation, wherein the third corresponding relation stores mapping between different control signals and different encryption algorithms;

the bus decryption module obtains a decryption algorithm corresponding to the encrypted data, and the decryption algorithm comprises the following steps: the bus decryption module obtains the control signal sent by the bus, and searches for a decryption algorithm corresponding to the control signal in a fourth corresponding relation, wherein the fourth corresponding relation stores mapping between different control signals and different decryption algorithms.

6. An apparatus for protecting bus data, the apparatus comprising:

the bus encryption module is used for encrypting the data to be sent to the first module according to the read operation or the write operation;

the encryption module is used for receiving the sensitive data through the bus encryption module, acquiring a first random number in a first random number generator corresponding to the first module, encrypting the sensitive data according to the first random number, and sending the acquired encrypted data to a bus;

the transmission module is used for sending the encrypted data to the bus decryption module through the bus;

the decryption module is used for receiving the encrypted data through the bus decryption module, acquiring a second random number in a second random number generator corresponding to the second module, decrypting the encrypted data according to the second random number, and sending the acquired sensitive data to the second module, wherein the second random number and the first random number are the same random numbers acquired by updating the same true random number for the same number of times;

a receiving module for receiving the sensitive data through the second module;

an update module, configured to send a random number update request to a random number consistency bus through a main module after each data transmission is completed, where the main module is a module that initiates data transmission in the first module and the second module;

controlling each first random number generator to update the first random number once through the random number consistency bus, and controlling each second random number generator to update the second random number once;

each first random number generator corresponds to one first module, each second random number generator corresponds to one second module, and the updated first random number is the same as the updated second random number;

the update module is further configured to:

updating the first random number of the first random number generator by the first random number generator once for each first random number generator in the first state; for each first random number generator in the second state, recording the number k of times to be updated of the own first random number through the first random number generator, after the data transmission of a first module corresponding to the first random number generator is completed, updating the own first random number k times, and setting the own state as the first state, wherein k is a positive integer;

for each second random number generator in the first state, updating the second random number of the second random number generator by the second random number generator once; for each second random number generator in the second state, recording the number n of times to be updated of the own second random number through the second random number generator, after the data transmission of a second module corresponding to the second random number generator is completed, updating the own second random number n times, and setting the own state as the first state, wherein n is a positive integer;

the second state is set for the first random number generator and the second random number generator when the first module corresponding to the first random number generator is transmitting data with the second module corresponding to the second random number generator and the data transmission of the other first module to the other second module is completed;

the first state is set for the first random number generator and the second random number generator after the first random number generator and the second random number generator in the second state complete random number updating.

7. A computer-readable storage medium having stored thereon at least one instruction which is loaded and executed by a processor to implement a method of protecting bus data as claimed in any one of claims 1 to 5.

8. A chip comprising a processor and a memory, said memory having stored therein at least one instruction that is loaded and executed by said processor to implement a method of protecting bus data as claimed in any one of claims 1 to 5.

Images