CN117675328A

CN117675328A - MIPI message encryption and decryption method and device

Info

Publication number: CN117675328A
Application number: CN202311633902.4A
Authority: CN
Inventors: 裴园; 李占斌; 周荣俊
Original assignee: Kungao New Core Microelectronics Jiangsu Co ltd
Current assignee: Kungao New Core Microelectronics Jiangsu Co ltd
Priority date: 2023-12-01
Filing date: 2023-12-01
Publication date: 2024-03-08

Abstract

The invention provides a method and a device for encrypting and decrypting MIPI messages, wherein the method comprises the following steps of: s1: generating an MIPI message; s2: judging whether the exit enables the MIPIsec function, if so, proceeding to step S3, otherwise, directly sending out the message; s3: the message enters a message analysis module, the SC is determined through analysis, the encryption information bound on the SC is obtained, and the step S4 is carried out; s4: sending the message and the encrypted information to an encryption module for encryption, and sending out after encryption; in the decryption direction, it includes: s5: after receiving the message, the MIPI message receiving module sends the message to the MIPI message analyzing module for analysis; s6: judging whether a message has a sectag head and the entrance enables MIPIsec, if so, obtaining decryption information bound on the SC through determining the SC, and proceeding to step S7, otherwise, directly sending to an upper application layer processing module for subsequent processing; s7: and sending the message and the decryption information to a decryption module for decryption, and sending the decrypted message to an upper application layer processing module for subsequent processing.

Description

MIPI message encryption and decryption method and device

Technical Field

The invention relates to the technical field of encryption and decryption of image data packets, in particular to a method and a device for encrypting and decrypting MIPI messages.

Background

MIPI (Mobile Industry Processor Interface) is an open standard initiated by the MIPI alliance and tailored for mobile application processors, with the aim of standardizing interfaces inside the handset, such as cameras, display interfaces, radio frequency/baseband interfaces, etc., thereby reducing the complexity of the handset design and increasing the design flexibility. In recent years, with the application of automatic driving, many automobiles are equipped with high-resolution cameras to assist the automatic driving, and the MIPI open standard is also applied in the automobile field.

Various symmetric encryption methods are currently proposed in the industry, such as SM4 (a block cipher standard adopted in china), AES (Advanced Encryption Standard), etc., that is, encryption and decryption use the same key, and plaintext can be encrypted into ciphertext, and ciphertext can be decrypted into plaintext. Further, the message integrity can be confirmed and authenticated by generating a fixed length of data, i.e., a MAC value (Message Authentication Code ).

The camera transmits the shot image to the processor for processing through the link, but because the image is transmitted in a plaintext form, no safety guarantee exists, a hacker is very easy to steal the picture information to infringe the privacy of the owner, and even the hacker can destroy the data, so that great potential safety hazard is caused to the driving process of the owner. There is currently no good method for encrypting MIPI messages in the industry.

Disclosure of Invention

The invention combines the encryption characteristic with the MIPI message by utilizing the expandability of symmetric encryption in cryptography, which is called MIPIsec (MIPI security) for short, and the MIPIsec encrypts and decrypts the MIPI message based on hardware, thereby improving the security of the MIPI message. The realization method is closer to the bottom layer, and can realize the line speed forwarding of the message.

In order to achieve the above purpose, the technical solution of the present invention provides a method for encrypting and decrypting an MIPI message, where in an encryption direction, the method includes the following steps: s1: the original image data generates MIPI messages through an upper application layer processing module, a group cladding module and a bottom protocol layer module; s2: judging whether the MIPIsec function is enabled by the outlet, if so, proceeding to step S3, otherwise, directly sending the MIPI message from the MIPI message sending module; s3: the MIPI message enters a MIPI message analysis module, an encryption channel SC is determined by analyzing the MIPI message, so that encryption information bound on the SC is obtained, and then the step S4 is carried out; s4: sending the MIPI message and the obtained encryption information to an encryption module for encryption processing, and sending the MIPI message to a MIPI message sending module for sending after the message encryption is completed; in the decryption direction, the method comprises the steps of: s5: after receiving the MIPI message, the MIPI message receiving module sends the MIPI message to the MIPI message analyzing module for analysis; s6: judging whether a sectag head exists in the message and the MIPIsec is enabled by the entry, if so, obtaining decryption information bound on the SC through determining the SC, and then proceeding to a step S7, otherwise, directly sending to an upper application layer processing module for subsequent processing; s7: and sending the MIPI message and the obtained decryption information to a decryption module for decryption, and sending the MIPI message and the obtained decryption information to an upper application layer processing module for subsequent processing after the decryption is finished.

Further, in step S3 and step S6, the process of determining SC includes: f1: obtaining a virtual data channel VC and a data type DT in DI information by analyzing the MIPI message; f2: judging whether the analyzed DT value is between 0x00 and 0x0F, if so, considering the message as a short packet and proceeding to step F3, otherwise, considering the message as a long packet and proceeding to step F4; f3: judging whether the short packet needs bypass MIPIsec processing, if so, directly sending the short packet without encryption and decryption processing, otherwise, carrying out encryption and decryption processing on the short packet and proceeding to step F4; f4: and carrying out SC searching processing.

Further, in step F4, the SC lookup processing mode includes the following three modes: taking VC+DT as key to make the wakeup of SC; taking VC as key to make the logo of SC; global mode, default to use one SC to do the SC's lookup.

Further, in step F4, if the lookup of the SC is successful, the encryption and decryption of the message are performed using the SC info, and if the lookup is unsuccessful, the message is discarded.

Further, in step S4, if the long packet is encrypted, the sectag is located after DI, the ICV is located before the CRC, encryption and integrity check are performed on the wc+ecc+data portion, and integrity check is performed on the DI field; if the short packet is encrypted, the sectag is located after the DI, the ICV is located after the data portion, the data portion is encrypted and integrity checked, and the DI field is integrity checked.

Further, at the transmitting end, after the ICV of 16Byte is obtained by calculating the content of the message with the key removed from the CRC is inserted in the data load, at the receiving end, the ICV is still obtained by performing inverse operation on the encrypted data by using the key, and whether the message is tampered is determined by judging whether the ICV carried by the message is equal to the ICV obtained by calculation.

Further, when the message is tampered, the message is directly discarded; when the message is determined not to be tampered, the decryption information bound by the corresponding encryption channel SC is searched for through the lookup to decrypt, if the decryption is successful, the sectag and the ICV are stripped off and restored into plaintext to be sent to the subsequent processing, and if the decryption is failed, the message is discarded.

The technical scheme of the invention also provides a device for encrypting and decrypting the MIPI message, which is used for executing the method, and comprises the following modules: the system comprises an upper layer application layer processing module, a group cladding module, a bottom layer protocol layer module, an MIPI message analysis module, an encryption module, an MIPI message sending module, an MIPI message receiving module and a decryption module.

Drawings

FIG. 1 is a schematic diagram of a packet encryption and decryption packet encapsulation according to the present invention;

FIG. 2 is a schematic diagram of the packet encryption and decryption packet encapsulation of the present invention;

FIG. 3 is a schematic diagram of an encryption/decryption architecture according to the present invention;

fig. 4 is a schematic diagram of the process of finding SCs of the present invention.

Detailed Description

The technical scheme of the present invention will be further described with reference to specific examples, but the present invention is not limited to these examples.

The camera performs corresponding image processing on the original data at the application layer at the transmitting end, including white balance/noise removal, color restoration and the like, then the processed data enter a group cladding to perform data segmentation and recombination, then the processed data are transmitted to a bottom protocol layer, the bottom protocol layer generates a packet head according to the data type, generates a check sequence forming a packet tail according to the data content, then the packet head, the data and the packet tail are formed and transmitted to a channel management layer, a channel management layer module reasonably distributes the data to each channel according to the gating condition of the channels, and then the data enter a physical layer through digital-to-analog conversion and are transmitted to a processor. After receiving the physical layer data, the receiving end unpacks the original image data according to the previous reverse order.

Taking a D-PHY transmit-receive data stream as an example to analyze a specific message format, two types of data packets are used for communication between the processor and the camera module: long packets (or long frames) and short packets (or short frames). The long packet is mainly composed of a packet header of 4 bytes, valid Data stuffing and a packet tail of 2 bytes, wherein the packet header is composed of a Data Identifier (DI) of 1Byte and a Data Count (WC) of 2 bytes representing the length of the stuffing Data, and the units are bytes and error detection (ECC) of 1 Byte. The valid data padding may fill in 0-65535 Byte data. The tail of the packet is used as a check value, the lower order is in front, and the check value can only detect errors and cannot correct the errors.

Where DI is in turn composed of virtual Data lanes VC (Vitual Channel) [7:6] and Data types DT (Data Type) [5:0 ]. The purpose of the VC is to provide separate channels for different data streams interleaved in the data streams, with virtual channel identifiers in the first two bits of the DI byte, the receiving end will identify the received VC identifiers and direct them to the corresponding channels, supporting a maximum of 4 data streams, with an effective VC identifier of 0 to 3. The DT value may specify the format and content of the payload data.

The short packet contains a total of four bytes, it contains only one header, there is no trailer, and the 16bit WC in the header is replaced by the data field of the short packet (the data field is different for DT and the padding is different).

When using MIPIsec to encrypt long packets, sectag (Security Tag) should be located after DI and ICV (Integrity Check Value) should be located before CRC (Cyclic Redundancy Check), the wc+ecc+data portion can be encrypted and integrity checked and the DI field can be integrity checked. The encryption channel selection may be based on VCs, i.e., one VC for each encryption channel, using different keys to encrypt the message, may be globally unique, i.e., using the same key to encrypt the message, or vc+dt may be used to encrypt the message at a finer granularity, providing an alternative granularity. And the decryption long packet searches the decryption information bound with the corresponding encryption channel according to the VC and DT carried by the message, and then decrypts the decryption information, if the decryption is successful, stripping the sectag and ICV to be restored into plaintext, and then sending the plaintext to subsequent processing, and if the decryption is failed, discarding the message.

For short packets, because the packet length is very short, if the packet is encrypted, the packet is lengthened, which additionally increases the burden of the transmission link, and in addition, the Data fields of the short packets all carry some control information, for example, if the short packets are Data Type frame synchronization (Frame Synchronization), the Data fields represent the frame number; if the Data Type of the short packet is line sync (Line Synchronization), the Data field represents the number of lines; but also some timing information such as the opening/closing of the shutter, the triggering of the flash, etc. The information has low protectiveness, so that the information can be selectively encrypted even if the information is stolen, the information can not be leaked, if the short packet is not required to be encrypted, the information is directly forwarded, and if the short packet is required to be encrypted, the encryption method is the same as long packet encryption and is not repeated. Here, it is necessary to explain how to distinguish short packets, and according to DT, if the DT value is 0x00-0x0f, it is a short packet.

If the short packet is selected not to be encrypted, the decryption end should also select not to decrypt the short packet for direct transparent transmission.

Fig. 1 shows a schematic diagram of a long packet encryption and decryption packet encapsulation. The left message encapsulation format of fig. 1 is a plain text MIPI packet, the specific format content has been described in detail above, the right message encapsulation format is an encrypted MIPI message, after the sectag is located at the Data ID of 1Byte, the ICV is located before the CRC, the content between the sectag and the ICV is encrypted (encrypted), these contents are transmitted in the whole transmission process of the message, the original Data can be actually obtained until the opposite end receives the message and decrypts the message, in addition, the message can obtain the message integrity check (authorized) after the message removes the CRC, after the sending end uses the key to calculate the ICV of 16Byte to insert the ICV of the message into the Data load, until the opposite end still uses the key to perform inverse operation on the encrypted Data to obtain the ICV, if the ICV carried by the message is equal to the calculated ICV, the message content is not tampered, if the ICV carried by the message is not equal to the calculated ICV, the message content is tampered, the mechanism is greatly protected, and the security of the Data is greatly protected. If the message is not tampered at the receiving end, the ciphertext is replaced by plaintext, and the sectag and the ICV are stripped for subsequent processing.

Fig. 2 shows a schematic diagram of short packet encryption and decryption packet encapsulation. The technical scheme is the same as the encryption and decryption process of the long packet, and repeated complaints are avoided.

Fig. 3 shows an encryption and decryption architecture design. In the encryption direction, the original image data passes through an upper application layer processing module, a group cladding module and a bottom protocol layer to generate an MIPI data message, whether an exit enables the MIPIsec function or not is judged, if the exit does not enable the MIPI data message, the message is directly sent out from an MIPI message sending module, if the exit does not enable the MIPI data message, an MIPI message analyzing module is enabled to analyze key information of the MIPI message, the key information is utilized to determine SC (specifically described in fig. 4), the SC (Secure Channel, encryption Channel) is bound with the encryption information, the obtained encryption information and the message are sent to the encryption module to be encrypted, and the message is sent to the MIPI message sending module to be sent out after being encrypted. The decryption direction, the MIPI message receiving module receives MIPI ciphertext, sends the MIPI ciphertext to the MIPI message analyzing module, analyzes MIPI message key information and judges whether sectag exists or not, wherein the judging can be carried out through the first two bytes of the sectag, if the first two bytes of the sectag are equal to the type (type is matched), the message is considered to be a sectag head, otherwise, the message is not encrypted, if the sectag head exists and the MIPIsec is enabled by an entrance, the key information is used for determining SC (specifically described in fig. 4), the SC is bound with decryption information, the obtained decryption information and the message are sent to the decryption module for decryption, and finally sent to the upper application layer processing module for subsequent processing after the decryption is finished.

Fig. 4 shows a find SC procedure. Under the condition that MIPIsec is enabled, firstly analyzing the MIPI message, acquiring the DI Info including a virtual Data channel VC (Vitual Channel) [7:6] and a Data Type DT (Data Type) [5:0], if the analyzed DT value is between 0x00 and 0x0f, considering the Data Type DT as a short packet, judging whether bypass MIPIsec process is needed for the short packet, if bypass is not needed, considering the short packet as direct outgoing without encryption and decryption processing, and if bypass is not needed, considering the short packet as encryption and decryption processing, and then searching for SC processing. If the DT value is not between 0x0 and 0xf, then long packets are considered, followed by a find SC process. The method comprises the steps of searching for the SCs, wherein one mode is to take VC+DT as key to serve as the key of the SCs, the other mode is to take VC as key to serve as the key of the SCs, and finally, the mode is global, one SC is used as the key of the SCs by default, namely, all received messages use one SC, a proper method for outputting the SCs can be selected according to different requirements, if the key of the SC is successful, SC info is used for encrypting and decrypting the messages, and if the key is unsuccessful, the messages are discarded.

It should be noted that the procedure for issuing the MIPIsec key is not within the scope of the present discussion, and that a person skilled in the art may flexibly select an appropriate method to adapt the present invention. It should be further appreciated that, although the above embodiment is described by taking the D-PHY transmit-receive data stream as an example, the present invention is equally applicable to the application scenarios of transceivers such as C-PHY, a-PHY, M-PHY, etc.

In an embodiment of the present invention, a method for encrypting and decrypting an MIPI message is provided, where in an encryption direction, the method includes the following steps: s1: the original image data generates MIPI messages through an upper application layer processing module, a group cladding module and a bottom protocol layer module; s2: judging whether the MIPIsec function is enabled by the outlet, if so, proceeding to step S3, otherwise, directly sending the MIPI message from the MIPI message sending module; s3: the MIPI message enters a MIPI message analysis module, an encryption channel SC is determined by analyzing the MIPI message, so that encryption information bound on the SC is obtained, and then the step S4 is carried out; s4: sending the MIPI message and the obtained encryption information to an encryption module for encryption processing, and sending the MIPI message to a MIPI message sending module for sending after the message encryption is completed; in the decryption direction, the method comprises the steps of: s5: after receiving the MIPI message, the MIPI message receiving module sends the MIPI message to the MIPI message analyzing module for analysis; s6: judging whether a sectag head exists in the message and the MIPIsec is enabled by the entry, if so, obtaining decryption information bound on the SC through determining the SC, and then proceeding to a step S7, otherwise, directly sending to an upper application layer processing module for subsequent processing; s7: and sending the MIPI message and the obtained decryption information to a decryption module for decryption, and sending the MIPI message and the obtained decryption information to an upper application layer processing module for subsequent processing after the decryption is finished.

In other embodiments of the present invention, there is also provided an apparatus for encrypting and decrypting an MIPI message, configured to perform the method as described above, where the apparatus includes the following modules: the system comprises an upper layer application layer processing module, a group cladding module, a bottom layer protocol layer module, an MIPI message analysis module, an encryption module, an MIPI message sending module, an MIPI message receiving module and a decryption module.

The invention combines the encryption characteristic with the MIPI message by utilizing the expandability of symmetric encryption in cryptography, and encrypts and decrypts the MIPI message based on hardware, thereby improving the security of the MIPI message. The realization method is closer to the bottom layer, and can realize the line speed forwarding of the message. In addition, the per VC and the per DT can be selected to output encryption channels, so that the encryption granularity can be flexibly selected, and the data security is further improved.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and improvements could be made by those skilled in the art without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. The MIPI message encryption and decryption method is characterized in that in the encryption direction, the method comprises the following steps:

s1: the original image data generates MIPI messages through an upper application layer processing module, a group cladding module and a bottom protocol layer module;

s2: judging whether the MIPIsec function is enabled by the outlet, if so, proceeding to step S3, otherwise, directly sending the MIPI message from the MIPI message sending module;

s3: the MIPI message enters a MIPI message analysis module, an encryption channel SC is determined by analyzing the MIPI message, so that encryption information bound on the SC is obtained, and then the step S4 is carried out;

s4: sending the MIPI message and the obtained encryption information to an encryption module for encryption processing, and sending the MIPI message to a MIPI message sending module for sending after the message encryption is completed;

in the decryption direction, the method comprises the steps of:

s5: after receiving the MIPI message, the MIPI message receiving module sends the MIPI message to the MIPI message analyzing module for analysis;

s6: judging whether a sectag head exists in the message and the MIPIsec is enabled by the entry, if so, obtaining decryption information bound on the SC through determining the SC, and then proceeding to a step S7, otherwise, directly sending to an upper application layer processing module for subsequent processing;

s7: and sending the MIPI message and the obtained decryption information to a decryption module for decryption, and sending the MIPI message and the obtained decryption information to an upper application layer processing module for subsequent processing after the decryption is finished.

2. The method according to claim 1, wherein in step S3 and step S6, the process of determining SC comprises:

f1: obtaining a virtual data channel VC and a data type DT in DI information by analyzing the MIPI message;

f2: judging whether the analyzed DT value is between 0x00 and 0x0F, if so, considering the message as a short packet and proceeding to step F3, otherwise, considering the message as a long packet and proceeding to step F4;

f3: judging whether the short packet needs bypass MIPIsec processing, if so, directly sending the short packet without encryption and decryption processing, otherwise, carrying out encryption and decryption processing on the short packet and proceeding to step F4;

f4: and carrying out SC searching processing.

3. The method according to claim 2, wherein in step F4, the SC lookup processing mode comprises three of:

taking VC+DT as key to make the wakeup of SC;

taking VC as key to make the logo of SC;

global mode, default to use one SC to do the SC's lookup.

4. A method according to claim 3, characterized in that in step F4, if the lock of the SC is successful, the SC info is used to decrypt the message, and if the lock is unsuccessful, the message is discarded.

5. The method according to claim 4, wherein, in step S4,

if the encryption processing is carried out on the long packet, the sectag is positioned behind DI, the ICV is positioned in front of CRC, encryption and integrity check are carried out on the WC+ECC+data part, and the integrity check is carried out on the DI field;

if the short packet is encrypted, the sectag is located after the DI, the ICV is located after the data portion, the data portion is encrypted and integrity checked, and the DI field is integrity checked.

6. The method of claim 5, wherein at the transmitting end, after the ICV of 16Byte obtained by calculating the content of the message excluding CRC using the key is inserted in the data load, at the receiving end, the ICV is still obtained by performing inverse operation on the encrypted data using the key, and whether the message is tampered is determined by judging whether the ICV carried by the message is equal to the ICV obtained by calculation.

7. The method of claim 6, wherein the step of providing the first layer comprises,

when the message is determined to be tampered, the message is directly discarded;

when the message is determined not to be tampered, the decryption information bound by the corresponding encryption channel SC is searched for through the lookup to decrypt, if the decryption is successful, the sectag and the ICV are stripped off and restored into plaintext to be sent to the subsequent processing, and if the decryption is failed, the message is discarded.

8. An apparatus for encrypting and decrypting MIPI messages, which is configured to perform the method according to any one of claims 1-7, and comprises the following modules: the system comprises an upper layer application layer processing module, a group cladding module, a bottom layer protocol layer module, an MIPI message analysis module, an encryption module, an MIPI message sending module, an MIPI message receiving module and a decryption module.