TW202433890A - Paired encryption-decryption method - Google Patents

Abstract

The present invention relates to a paired encryption-decryption Method. At least one control device is connected to multiple node devices. The control device obtains ID lists of all node devices. The control device uses a PUF encryption value to generate a pre-shared key. The control device sends the pre-shared key and the ID lists to the multiple node devices. Any of two node devices confirm the security between the two node device through the pre-shared key, and share the respective initial value of the two node devices. Then, a shared joint key of any of the two node devices is generated by encryption for communication security between the any of the two node devices.

Description

Pairwise encryption and decryption method

The present invention relates to a pairwise encryption and decryption method, in particular, a method combining identity authentication, P2P encryption and key management, which uses PUF to generate a shared key, and then verifies the security between any two nodes based on the shared key, and then shares the initial values of any two nodes and encrypts them to generate a shared joint key for communication security between any two nodes.

With the current development of networks and semiconductors, the Internet of Things (IoT) is experiencing a golden year. At the same time, the Internet of Things (IoT) in the manufacturing environment faces the key issue of information security. With the vigorous development of network technology, the attack methods are becoming more and more diverse, and traditional defense solutions are no longer suitable for the manufacturing environment. Therefore, the industry will need a lighter and more powerful security mechanism to cope with future security challenges.

Therefore, confidentiality, integrity, and availability are important as basic data processing methods. In confidentiality, the scope of discussion is how to ensure the privacy of data during transmission and storage, and avoid related attacks or other factors that may cause the data to be accidentally disclosed.

Simply put, in the IoT environment, if data is intercepted and stolen before it reaches its destination, causing the accuracy of the information to be tampered with, this is an example of violating the confidentiality of the data. Therefore, if data is changed by other factors before it is published or sent to its true destination, it is also a confidentiality issue. Confidential data must be encrypted when it is transmitted and stored to ensure that the legitimate performance of the information is indeed transmitted.

When it comes to information security in the Internet of Things, people usually think of software and encrypted network connections first. However, in addition to network-level security protection, physical devices also pose threats. Once counterfeit chips or other problems occur, hackers may remotely control devices through the network to obtain keys and other sensitive information, thereby causing losses to the company. Software-based information security design is no longer sufficient to provide comprehensive protection, which is why hardware-based security technology has begun to gain popularity year by year.

PUF is such a hardware security technology. The key storage of PUF technology is different from traditional practices in that PUF technology uses the natural random electrical changes inherent in SRAM to turn it into a secret password key similar to a unique "fingerprint", which can serve as the basis of the security subsystem.

However, if all nodes need to use PUF technology for encryption and decryption during communication, it will be very troublesome and the cost of equipment installation will also be very high.

Therefore, this case first uses the circuit characteristics of SRAM to create a physically unclonable function (PUF) to generate a unique value that is not easy to be copied, and the key generated in this way is used to create a secure channel between two nodes to ensure the reliability, confidentiality and integrity of the (point-to-point) communication between the transmission nodes. After the secure channel is created, the two nodes no longer use the key originally generated by PUF, but instead use the Diffie-Hallman method to generate a shared key for bilateral communication encryption and decryption. Because of the additional encryption and decryption mechanism, the machine can filter the packet through this product when receiving the packet, thereby enhancing the security of the communication transmission between the machines. Therefore, this invention should be an optimal solution.

The paired encryption and decryption method of the present invention comprises the following steps: (1) at least one control device is connected to a plurality of node devices, the control device obtains the ID list data of all node devices, and the control device uses a PUF encryption value to encrypt and generate a shared key initial value, and the control device further performs hashing operation on the shared key initial value to obtain a pre-shared key; (2) the control device transmits the ID list data and the pre-shared key to all node devices, and any two node devices are connected and communicated with each other, wherein any two node devices are a first node device and a second node device, and the first node device uses the pre-shared key to encrypt a second initial value and transmits it to the second node device; (3) The second node device uses the pre-shared key to decrypt to obtain the second initial value, performs hashing on the second initial value to obtain a first hash value, and the second node device uses the pre-shared key to encrypt a third initial value and the first hash value, and transmits the encrypted data to the first node device; (4) The first node device uses the pre-shared key to decrypt to obtain the third initial value and the first hash value, performs hashing on the second initial value to obtain a second hash value, and compares the first hash value with the second hash value to determine whether the communication with the second node device is secure; (5) The first node device and the second node device respectively use the second initial value and the third initial value to encrypt and generate a combined key initial value. The first node device and the second node device further perform hashing on the combined key initial value to obtain a combined key; (6) The first node device performs hashing on the third initial value to obtain a third hash value, and encrypts the third hash value using the combined key and transmits it to the second node device; (7) The second node device uses the joint key to decrypt to obtain the third hash value, the second node device performs hashing on the third initial value to obtain a fourth hash value, and compares the third hash value with the fourth hash value to determine whether the communication with the first node device is secure.

More specifically, the control device is electrically connected to a static random access memory, and the static random access memory is electrically connected to generate a random data after each startup. The control device receives the random data and distinguishes the random data into multiple addresses and multiple sets of encryption values, wherein each set of encryption values further corresponds to one of the addresses, and the control device takes out multiple sets of continuous or/and non-continuous encryption values as the PUF encryption value. The control device uses the PUF encryption value to encrypt a first initial value (mutually exclusive or calculation or other encryption methods) to generate the shared key initial value.

More specifically, the first initial value is randomly generated by the control device.

More specifically, the second initial value is randomly generated for the first node device, and the third initial value is randomly generated for the second node device.

More specifically, the control device, the first node device and the second node device are capable of performing hashing calculations using a secure hash algorithm (SHA).

More specifically, the first node device uses the pre-shared key to encrypt a first node security information into a first encrypted information, and the first node security information includes the second initial value, a first timestamp and a first node ID. After the second node device uses the pre-shared key to decrypt the first encrypted information, the second node device further verifies whether the first timestamp is correct and verifies whether the first node ID is located in the ID list data.

More specifically, the first node device uses the joint key to encrypt a first node communication information into a third encrypted information, and the first node communication information includes the third hash value and a third timestamp. After the second node device uses the joint key to decrypt the third encrypted information, the second node device further verifies whether the third timestamp is correct.

More specifically, the first node device uses the pre-shared key to encrypt a second node security information into a second encrypted information, and the second node security information includes the third initial value, a second timestamp and a second node ID. After the first node device uses the pre-shared key to decrypt the second encrypted information, the second node device further verifies whether the second timestamp is correct and verifies whether the second node ID is located in the ID list data.

Other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings.

Please refer to Figure 1. The overall architecture of the paired encryption and decryption method of this case includes a static random access memory 1 and a control device 2. The control device 2 is electrically connected to the static random access memory 1, and the control device 2 has a power interface (not shown in the figure), and the power interface is connected to a power line (not shown in the figure) to provide the power required for operation.

The static random access memory 1 generates a random data (fixed and random value) after each power-on startup. In the embodiment of the present case, the static random access memory 1 used is a SRAM chip (for example, similar to Cypress's CY62256N, 256-Kbit (32 K × 8) Static RAM).

The static random access memory 1 used in the present embodiment is a packaged product, and therefore has structural features of a power interface (not shown in the figure) and a transmission interface (not shown in the figure). It is connected to the control device 2 through the transmission interface and the cable (not shown in the figure), and the power interface is used to connect to the power line (not shown in the figure) to provide the power required for operation.

In addition, the static random access memory 1 can also be connected to a circuit substrate (not shown in the figure), and the circuit substrate also has structural features of a power interface (not shown in the figure) and a transmission interface (not shown in the figure). Therefore, the static random access memory 1 is connected to the control device 2 through the transmission interface and the cable (not shown in the figure) of the circuit substrate, and the power interface of the circuit substrate is used to connect the power line to provide the power required for operation.

In addition, the static random access memory 1 and the control device 2 can be on the same circuit substrate (not shown in the figure). The static random access memory 1 or the circuit substrate has a transmission interface (not shown in the figure), so it can be connected to the control device 2 through the transmission interface and the cable. The circuit substrate also has a power interface (not shown in the figure) for connecting the power line to provide the static random access memory 1 and the control device 2 with the power required for operation.

As shown in FIG. 2 , the control device 2 at least includes a processor 21 and a readable recording medium 22 (the readable recording medium 22 is a memory element with a memory function). The readable recording medium 22 stores the first initial value, which is randomly generated by the control device 2 or obtained by an external device.

The encryption unit 221 is used to receive the random data generated by the static random access memory 1, and according to the bit width of the first initial value, the random data is divided into multiple addresses and multiple sets of encryption values (each set of encryption values corresponds to one of the addresses), and the multiple addresses divided by the encryption unit 221 include an initial address, an end address and a plurality of addresses continuously arranged between the initial address and the end address.

The encryption unit 221 takes the initial address as the starting point, and then selects a new starting address according to the collision offset set by the encryption unit 221, and selects multiple encryption values from the new starting address, and takes out multiple sets of continuous or/and non-continuous encryption values as the PUF encryption value, and then encrypts the first initial value with the PUF encryption value (mutually exclusive or calculation or other encryption methods) to generate the shared key initial value.

The encryption unit 221 performs hashing operation on the initial value of the shared key using a secure hash algorithm (e.g., SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256) to obtain a pre-shared key.

The encryption unit 221 further detects and corrects errors in the data bits of the random data through a Hamming code.

The control device 2 is connected to a plurality of node devices. In this case, only the first node device 3 and the second node device 4 are used as implementation examples.

As shown in FIG. 3 , the first node device 3 at least includes a processor 31 and a readable recording medium 32. The readable recording medium 32 stores the second initial value. The second initial value is randomly generated by the first node device 3 or obtained from an external device.

The readable recording medium 32 further has a first encryption/decryption unit 321, which can receive the ID list data and the pre-shared key, and first use the pre-shared key to decrypt to obtain a third initial value and a first hash value, and then perform a hashing operation on the second initial value to generate a second hash value for comparison with the first hash value transmitted by the second node device 4 to confirm whether the communication with the second node device is secure.

The first encryption/decryption unit 321 can further encrypt the second initial value and the third initial value to generate a combined key initial value, and perform hashing operation on the combined key initial value to obtain a combined key, and then perform hashing operation on the third initial value to generate a third hash value, and then transmit the third hash value to the second node device 4 for verification.

As shown in FIG. 4 , the second node device 4 at least includes a processor 41 and a readable recording medium 42. The readable recording medium 42 stores the third initial value. The third initial value is randomly generated by the second node device 4 or obtained from an external device.

The readable recording medium 42 further has a second encryption and decryption unit 421, which can receive the ID list data and the pre-shared key, and first use the pre-shared key to decrypt to obtain a second initial value, and use the pre-shared key to perform hashing calculations on the second initial value to generate a first hash value, and then transmit the first hash value to the first node device 3 for verification.

The second encryption/decryption unit 421 is further capable of encrypting the second initial value and the third initial value to generate a combined key initial value, and performing hashing operation on the combined key initial value to obtain a combined key, and then using the combined key to perform decryption to obtain a third hash value, and then performing hashing operation on the third initial value to generate a fourth hash value for comparison with the third hash value transmitted by the second node device 4 to confirm whether the communication with the first node device is secure.

After security is confirmed, the first node device 3 and the second node device 4 will store the joint key. In the future, the communication between the first node device 3 and the second node device 4 will be encrypted and decrypted through the joint key. At the same time, since the joint key is generated by encrypting and hashing the second initial value of the first node device 3 and the third initial value of the second node device 4, the joint key will not be obtained by other node devices.

As shown in FIG. 5, it is a flowchart of the paired encryption and decryption method of the present invention, and its steps are: (1) At least one control device is connected to multiple node devices, and the control device obtains the ID list data of all node devices, and the control device uses a PUF encryption value to encrypt and generate a shared key initial value, and the control device further performs hashing calculation on the shared key initial value to obtain a pre-shared key 501; (2) The control device transmits the ID list data and the pre-shared key to all node devices, and any two node devices are connected and communicated with each other, wherein any two node devices are a first node device and a second node device, and the first node device uses the pre-shared key to encrypt a second initial value and transmit it to the second node device 502; (3) The second node device uses the pre-shared key to decrypt to obtain the second initial value, performs hashing on the second initial value to obtain a first hash value, and the second node device uses the pre-shared key to encrypt a third initial value and the first hash value, and transmits the encrypted data to the first node device 503; (4) The first node device uses the pre-shared key to decrypt to obtain the third initial value and the first hash value, performs hashing on the second initial value to obtain a second hash value, and compares the first hash value with the second hash value to determine whether the communication with the second node device is secure 504; (5) The first node device and the second node device use the second initial value and the third initial value to encrypt and generate a combined key initial value, and the first node device and the second node device further perform hashing on the combined key initial value to obtain a combined key 505; (6) The first node device performs hashing on the third initial value to obtain a third hash value, and encrypts the third hash value using the combined key and transmits it to the second node device 506; (7) The second node device uses the joint key to decrypt to obtain the third hash value, the second node device performs hashing on the third initial value to obtain a fourth hash value, and compares the third hash value with the fourth hash value to determine whether the communication with the first node device is secure 507.

In step 501, the control device first sets all ID list data (id _all ), which includes the IDs of all node devices.

In step 501, the control device randomly selects a first initial value (V _random ), obtains a PUF encrypted value (V _PUF ), and performs a mutual exclusion or operation (V _hash = K _random ⊕ V _PUF ) on the first initial value (V _random ) and the PUF encrypted value (V _PUF ) to generate a shared key initial value (V _hash ), and then performs a hash operation (hash) on the shared key initial value (V _hash ) to obtain a pre-shared key K _ps (K _ps = H _SHA−256 (V _hsah )).

Steps 502 to 505 start to generate a joint key using the Diffie-Hallman method.

In step 502, the control device transmits the pre-shared key ( _Kps ) and the ID list data ( _idall ) to all nodes through the encrypted channel established by VPN, and all nodes store the pre-shared key ( _Kps ) and the ID list data ( _idall ) in the memory.

In step 502, the first node device acts as a node end that initiates communication. The first node device randomly generates a second initial value (VN _init ). Afterwards, the first node device generates a first timestamp (timestamps) T and first encryption information (E _ps1 ), wherein the first encryption information (E _ps1 ) is generated by the first node device using a pre-shared key (K _ps ) to encrypt the first node security information (mutually exclusive or calculation or other encryption methods are acceptable), and the first node security information includes the second initial value (VN _init ), the first node device ID (id _init ) and the first timestamp (timestamps) T. Afterwards, the first node device transmits the first encryption information (E _ps1 ) to the second node device.

In step 503, the second node device serves as a responder receiving communication. After receiving the first encrypted information (E _ps1 ), the second node device can use the pre-shared key (K _ps ) to decrypt the first encrypted information (E _ps1 ) to obtain the second initial value (VN _init ), the first node device ID (id _init ) and the first timestamp (timestamps) T, and then confirm whether the first timestamp (timestamps) T is correct, and verify whether the first node device ID (id _init ) is located in the ID list data (id _all ).

In step 503, if the verification is correct, the second node device randomly selects a third initial value (VN _response ), and then performs a hash operation (hashing) on the second initial value (VN _init ) to obtain a first hash value HN _init (HN _init = H _SHA−256 (VN _init )).

In step 503, the second node device generates a second timestamp (timestamps) T and second encryption information ( _Eps2 ), wherein the second encryption information ( _Eps2 ) is generated by the second node device using a pre-shared key ( _Kps ) to encrypt (mutually exclusive or calculation or other encryption methods are acceptable) a second node security information, and the second node security information includes a first hash value (HN _init ), a third initial value (VN _response ), a response node ID (id _init ) and a second timestamp (timestamps) T. Afterwards, the second node device transmits the second encryption information ( _Eps2 ) to the first node device.

In step 504, after receiving the second encrypted information (E _ps2 ), the first node device uses the pre-shared key (K _ps ) to decrypt the second encrypted information (E _ps2 ) to obtain the first hash value (HN _init ), the third initial value (VN _response ) and the second timestamp (timestamps) T, and then confirms whether the second timestamp (timestamps) T is correct, and verifies whether the response node ID (id _init ) is in the ID list (id _all ).

In step 504, the first node device hashes the second initial value (VN _init ) to obtain a second hash value (HN _init ), and confirms whether the first hash value (HN _init ) is equal to the second hash value (HN _init ). If the confirmation is correct, the nodes are secure.

In step 505, the first node device performs an exclusive OR operation (XOR) on the second initial value (VN _init ) and the third initial value (VN _response ) to generate a joint key initial value V _hash (V _hash = VN _init ⊕ VN _response ), and then performs a hash operation (hashing) on the joint key initial value (V _hash ) to obtain a joint key K _common (K _common = H _SHA−256 (VN _init ⊕ VN _response )).

In step 505, the first node device also performs an exclusive OR operation (XOR) on the second initial value (VN _init ) and the third initial value (VN _response ) to generate a joint key initial value V _hash (V _hash = VN _init ⊕ VN _response ), and then performs a hash operation (hashing) on the joint key initial value (V _hash ) to obtain a joint key K _common (K _common = H _SHA−256 (VN _init ⊕ VN _response )).

In step 506, the first node device generates a third timestamp T and performs a hash operation on the third initial value (VN _response ) to obtain a third hash value (HN _response ). The first node device then generates a third encrypted information (E _ps3 ), wherein the third encrypted information (E _ps3 ) is generated by the first node device using a joint key (K _common ) to encrypt a first node communication information (mutually exclusive or calculation or other encryption methods are acceptable), and the first node communication information includes the third hash value (HN _response ) and the third timestamp T. Afterwards, the first node device transmits the third encrypted information (E _ps3 ) to the second node device. At the same time, the joint key (K _common ) is stored in the memory of the first node device.

In step 507, the second node device uses the joint key (K _common ) to decrypt the third encrypted information (E _ps3 ) to obtain a third hash value (HN _response ) and a third timestamp (timestamps) T, and then confirms whether the third timestamp (timestamps) T is correct.

In step 507, the second node device hashes the third initial value (VN _response ) to obtain a fourth hash value (HN _response ), and confirms whether the third hash value (HN _response ) is equal to the third hash value (HN _response ). If the confirmation is correct, the joint key (K _common ) is stored in the memory of the second node device.

In this way, security verification is completed. When the first node device and the second node device want to communicate, the information can be encrypted through a joint key (mutual exclusion, calculation or other encryption methods are possible), and at the same time, mutual verification can be performed after hashing to prevent the packet from being intercepted and modified in the middle.

This case is more special for PUF encryption value, and the implementation process of PUF encryption value generation is: (1) Start operation 600, first start the static random access memory 601, check whether the voltage supplied to the static random access memory is within the allowable value 602, if it is judged to be, initialize the chip pins of the processor of the control device 603, if it is judged to be not, shut down the static random access memory 604; (2) Check whether the value of each chip pin of the processor is within the normal range 605, if not, enter the process 604, if yes, the control device sends a control signal to the static random access memory 606; (3) Determine whether the return value 607 (random data) from the static random access memory is received. If it is determined that it is not received, the system operation is interrupted for a certain period of time 608. If the process 607 determines that it is received, it is further determined whether the Chinese code exists 609. If the process 609 determines that the Chinese code exists, the return value is checked for errors through the Chinese code 612. If the process 609 determines that the Chinese code does not exist, the return value is added to the Chinese code 610, and the Chinese code and the return value are packaged 611, and then the process 612 is entered; (4) After process 612 determines that there is no error, it packages the return value 613 and inputs the encrypted target value (first initial value) 616. If process 612 determines that there is an error, it attempts to repair 614 and then determines whether the repair is successful 615. If process 615 does not repair successfully, it returns to process 608. If the repair is successful, it enters process 616; (5) Then input the collision offset 617 and then test whether the collision offset is normal 618. If process 618 tests that the collision offset is abnormal, clear the collision offset 619 and enter process 617. If process 618 tests that the collision offset is normal, call the return value 620; (6) Determine whether the encryption unit successfully obtains the return value 621. If process 621 determines that the encryption unit does not obtain the return value, clear all caches in the memory (readable recording medium) 623, and after process 623 is cleared, enter process 606. If process 621 determines that the encryption unit has obtained the return value, convert the encrypted target value into a binary system (e.g., binary) 622; (7) Then, the memory is aligned 624 and checked whether the memory is aligned 625. If the process 625 determines that the memory is not aligned, the process 623 is entered. If the process 625 determines that the memory is aligned, the memory space is configured 626 and the memory space is checked whether it is successfully configured 627. If the process 627 determines that the memory is not successfully configured, the process 623 is entered. If the process 627 checks that the memory is successfully configured, a random number is generated 628 and the random number is stored 629. (8) In addition, process 630 can be added to determine whether the random number is repeated. If process 630 determines that it is repeated, it returns to process 619. If process 630 determines that it is not repeated, it ends process 631.

The above process mainly covers the overall implementation process from hardware startup to random number generation and checking whether the random number is repeated. The detailed technical description of the above process is as follows.

Processes 601-607 are mainly to start the static random access memory, and the static random access memory will generate fixed and random data. For example, the 15 address lines of the static random access memory (SRAM) are mapped to a 2 ¹⁵ power memory array group (control device). The electronic random state characteristics of the SRAM at startup will generate a unique random value (return value). Through sampling by the control device 2, a set of 2 ¹⁵ bytes of random binary array can be obtained.

This scheme can distinguish multiple addresses and multiple sets of encryption keys from the random data (random binary array). For example, after obtaining 2 ¹⁵ bytes, if it is divided into five sets of encryption keys, the address length of each set of encryption keys is 2 ³ bytes.

In the actual implementation of this case, the shortest length of the address retrieved is 2 ³ bytes and the longest is 2 ¹⁵ bytes, and the number of encryption key groups retrieved is at least one, and there is no limit on the maximum number.

The length of the addresses of the encryption keys distinguished in this case can be the same length or different lengths. The above example of 2 ¹⁵ bytes is the same length, but it can also be different lengths. For example, after obtaining 2 ²⁰ bytes, if it is distinguished into four groups of encryption keys, these four groups of encryption keys can be the first group (2 ³ bytes), the second group (2 ⁵ bytes), the third group (2 ⁸ bytes), and the fourth group (2 ⁴ bytes). Therefore, it is possible to set and distinguish multiple addresses and multiple groups of encryption keys according to needs.

In process 608, when it is determined that no return value is received, the system operation is interrupted and the random value (return value) is obtained again.

Process 609-615 uses a Hamming code (check code) to check whether the returned value has errors. The Hamming code check is described as follows (if there are too many error bits, it may not be repaired. In this case, the process will enter process 408): (1) The check code is attached to the data for inspection and verification. The steps are as follows. First, K bits are taken as the check code. M is the name of the data. M <= ²ⁿ , K = n + 1. Assuming that the data is 8 bits, then 8 <= ²³ , K = 3 + 1, the check code (K) is 4 bits. As mentioned above, the Hamming code is a combination of data and check code, 8 bits (original data) + 4 bits (check code), so the Hamming code is composed of 12 bits, as shown in Table 1. (2) P1 to P12 are bit positions, and the check codes are C1, C2, C4, C8 (2 ⁿ ). The data is filled in sequentially. Here, the data is 10010110 as shown in Table 2. One thing to note is that the check code needs to be left blank, so the data is skipped. Then we pick out the bits with 1 in the data, encode them for XOR operation, and get the check code 0110. Fill the result back in and repeat the above steps. We can determine whether a coding is wrong. We will check the data after adding the check code, encode the positions with 1 bits for XOR operation. If the results are all 0, the coding is verified to be correct. Bit Address P12 P11 P0 P09 P08 P07 P06 P05 P04 P03 P02 P01 Bit encoding 1100 1011 1010 1001 1000 0111 0110 0101 0100 0011 0010 0001 Original data 1 0 0 1 0 1 1 0 Check code C8 C4 C2 C1 Table 1 Hamming Code Bit Address P12 P11 P0 P09 P08 P07 P06 P05 P04 P03 P02 P01 Bit encoding 1100 1011 1010 1001 1000 0111 0110 0101 0100 0011 0010 0001 Original data 1 0 0 1 0 1 1 0 Check code 0 1 1 0 Table 2 Hamming Code + Check Code (3) Try to modify the original data at position P05, as shown in Table 3. Change the original 1 to 0 and then perform the XOR operation again. It is obvious that the encoding is wrong. The error bit is at P05 (0101). Bit Address P12 P11 P0 P09 P08 P07 P06 P05 P04 P03 P02 P01 Bit encoding 1100 1011 1010 1001 1000 0111 0110 0101 0100 0011 0010 0001 Original data 1 0 0 1 0 1 0 0 Check code 0 1 1 0 Table 3 Chinese code detection

Process 616~619 is to input the encryption target value (first initial value) and the collision offset. The collision offset is explained as follows: (1) After obtaining the value, we take out the value with a total length of 6 bytes (48 bits) from the 2 ¹⁵ binary random array as the value for encryption and decryption operations (similar to a hash function). (2) After that, we use program operation as a test to perform an XOR operation on the above sampled 6-byte original sample value and the original input value to be encrypted (must be converted to binary first). Under normal circumstances, a unique value will be generated. However, if the original input values are different but the same output is generated, this technology adds a collision offset so that all the original input values can generate different and stable outputs. (3) As shown in Table 4, assuming that the length of random data that can be retrieved is 48 bits, multiple addresses [0]~[6] and multiple sets of encryption keys can be distinguished. Bit Address [0] [1] [2] [3] [4] [5] Encryption Key 11011011 01011110 11100110 01011001 11010110 00001111 Table 4 Random data partition example (4) If you want to use 24 bits for encryption, set hash(x,i,j,k), where x is the encryption target value, i is the collision offset, j is the number of encryption groups, and k is the address interval hash(x,i). When setting hash(5,0,3,1), take out the values of [0]~[2] and the encryption target value (5, binary is 00000101) to encrypt (mutual exclusion or operation or other encryption method) to generate a random value. (5) Since the original default collision offset is 0, all extraction starts from [0]. Therefore, [0] is the initial address and [5] is the end address. [1] to [4] are the addresses that are consecutively arranged between the initial address and the end address. When the collision offset is changed, if the collision offset is 1, the original extraction starting point is shifted from [0] to [1]. At this moment, [1] becomes the new starting address, and then multiple consecutive encryption keys are selected from the new starting address to encrypt the first initial value (mutually exclusive or calculation or other encryption methods) to generate a random value. (6) As described in process 630, different inputs may result in the same random number output (possibly due to the instability of the static random access memory or the natural generation of the same random number after XOR encryption). In such a case, the collision offset can be changed. If the collision offset is 1, the values of [1] to [3] are taken out and encrypted with the encryption target value (5, binary 00000101) (mutual exclusion or operation or other encryption method) to generate a random number value. (7) Since the length initially retrieved is fixed, for example, 48 bits can distinguish addresses from [0] to [5]. If 24 bits are to be used for encryption, the collision offset can only be from [0] to [3]. If it exceeds [3], it cannot be captured normally. Therefore, process 418 needs to determine whether the input collision offset is normal. If it is determined to be abnormal, the collision offset will be cleared and re-entered. (8) In addition to selecting multiple consecutive addresses, multiple non-consecutive addresses can also be selected. For example, the length of random data that can be retrieved is 256 bits. After distinguishing addresses [0]~[32] and multiple sets of encryption keys, if hash(x,1,5,3) is set, non-consecutive addresses ([1], [4], [7], [10], [13]) will be retrieved to encrypt x. (9) In addition to selecting at fixed intervals, random intervals can also be selected. For example, if the intervals are 1, 3, 4, 7, [1], [2], [5], [9], [16] will be retrieved. (10) In addition to fixed-interval selection, continuous and non-continuous mixed selection is also possible. For example, if the interval is 1, 1, 4, 7, [1], [2], [3], [7], [14] will be selected.

Process 620~627 is to start using the encryption key retrieved after inputting the collision offset. First, it is necessary to recheck whether the return value still exists. If the return value no longer exists, it is necessary to obtain the return value again. After that, the encrypted target value (first initial value) is converted into binary, and then the memory is aligned and the memory space is configured to confirm that there is enough memory address and space to store the random number after it is generated.

In addition, if the encryption key and the encryption target address are different, they will also be matched through memory alignment so that the encryption key can be used to encrypt the encryption target. For example, if the encryption key address length is 8 bits (such as 11011011), and the encryption target address is 16 bits (such as 1101101111011101), the encryption key address length can be aligned to 0000000011011011 to facilitate encryption.

In process 628-631, random numbers are generated and stored, and then repeated random numbers are verified. If repeated random numbers are found, the collision offset can be cleared and the collision offset can be re-entered to avoid the same random number output due to different inputs.

The different inputs mentioned in this case are different encryption target values (first initial value) that get the same random number output. By changing the collision offset, such a situation can be largely avoided (when we throw a value a in, a value a’ will be generated. The mechanism of this case is to stably generate a’ every time a is thrown in. If b is thrown in and the output value is still a’, a detection will be performed, thereby increasing the collision offset for correction, so that the value b can stably output b’).

The advantages of the pairwise encryption and decryption method provided by the present invention compared with other conventional technologies are as follows: (1) This case uses the circuit characteristics of SRAM to produce a physically unforgeable function (PUF) to generate a unique value that is not easily copied, and the key generated by this is used to create a secure channel between two nodes to ensure the reliability, confidentiality and integrity of the communication between the two transmission nodes. (2) After using the key generated by PUF to verify the channel, the two nodes no longer use the key originally generated by PUF, but instead use the Diffie-Hallman method to generate a joint key for bilateral communication encryption and decryption. Because there is an additional layer of encryption and decryption mechanism, the technology of this case can be used to filter packets when receiving packets, thereby enhancing the security of communication transmission between nodes. (3) This case integrates the physical unforgeable function (PUF) into the existing key generation method to generate a unique and difficult to copy true random number. It also uses lightweight and energy-saving characteristics. Therefore, after the secure channel is created, the communication between nodes and key re-authentication will be encrypted using a joint key, and there is no need to activate the PUF. Therefore, the control device only needs to initialize the PUF module once, and hashing is also used to improve the stability of the value generated by the PUF. (4) This case adds a layer of node protection to the network environment, creating a lightweight, reliable, and trusted secure channel for data transmission. In addition, the data will be encrypted to make it difficult for malicious people to intercept packets or input malicious parameters, thereby improving the security of information technology in the network environment.

The present invention has been disclosed as above through the above-mentioned embodiments, but they are not used to limit the present invention. Anyone familiar with this technical field and having common knowledge can make some changes and modifications without departing from the spirit and scope of the present invention after understanding the above-mentioned technical features and embodiments of the present invention. Therefore, the scope of patent protection of the present invention shall be determined by the definition of the claim items attached to this specification.

1: static random access memory 1 2: control device 2 21: processor 21 22: readable recording medium 22 221: encryption unit 221 3: first node device 3 31: processor 31 32: readable recording medium 32 321: first encryption unit 321 4: second node device 4 41: processor 41 42: readable recording medium 42 421: second encryption unit 421

[Figure 1] is a schematic diagram of the overall structure of the paired encryption and decryption method of the present invention. [Figure 2] is a schematic diagram of the structure of the control device of the paired encryption and decryption method of the present invention. [Figure 3] is a schematic diagram of the structure of the first node device of the paired encryption and decryption method of the present invention. [Figure 4] is a schematic diagram of the structure of the second node device of the paired encryption and decryption method of the present invention. [Figure 5] is a schematic diagram of the flow chart of the paired encryption and decryption method of the present invention. [Figure 5] is a schematic diagram of the flow chart of the paired encryption and decryption method of the present invention. [Figure 6A] is a flow chart of the random number generation step of the paired encryption and decryption method of the present invention. [Figure 6B] is a flow chart of the random number generation step of the paired encryption and decryption method of the present invention. [Figure 6C] is a flow chart of the random number generation step of the paired encryption and decryption method of the present invention.

1: Static random access memory

2: Control device

3: First node device

4: Second node device

Claims (8)

A pairwise encryption and decryption method, the steps of which are: At least one control device is connected to multiple node devices, the control device obtains the ID list data of all node devices, and the control device uses a PUF encryption value to encrypt and generate a shared key initial value, and the control device further performs hashing calculation on the shared key initial value to obtain a pre-shared key; The control device transmits the ID list data and the pre-shared key to all node devices, and any two node devices are connected and communicated with each other, wherein any two node devices are a first node device and a second node device, and the first node device uses the pre-shared key to encrypt a second initial value and transmit it to the second node device; The second node device uses the pre-shared key to decrypt to obtain the second initial value, performs hashing on the second initial value to obtain a first hash value, and the second node device uses the pre-shared key to encrypt a third initial value and the first hash value, and transmits them to the first node device; The first node device uses the pre-shared key to decrypt to obtain the third initial value and the first hash value, performs hashing on the second initial value to obtain a second hash value, and compares the first hash value with the second hash value to determine whether the communication with the second node device is secure; The first node device and the second node device use the second initial value and the third initial value to encrypt and generate a combined key initial value, and the first node device and the second node device further perform hash calculations on the combined key initial value to obtain a combined key; The first node device performs hash calculations on the third initial value to obtain a third hash value, and uses the combined key to encrypt the third hash value and transmit it to the second node device; The second node device uses the joint key to decrypt to obtain the third hash value, the second node device performs hashing on the third initial value to obtain a fourth hash value, and compares the third hash value with the fourth hash value to determine whether the communication with the first node device is secure. A paired encryption and decryption method as described in claim 1, wherein the control device is electrically connected to a static random access memory, and the static random access memory is electrically connected to generate a random data after each startup, and the control device receives the random data and divides the random data into multiple addresses and multiple sets of encryption values, wherein each set of encryption values further corresponds to one of the addresses, and the control device takes out multiple sets of continuous and/or non-continuous encryption values as the PUF encryption value, and the control device uses the PUF encryption value to encrypt a first initial value to generate the shared key initial value. The pairwise encryption and decryption method as described in claim 1, wherein the first initial value is randomly generated by the control device. The paired encryption and decryption method as described in claim 1, wherein the second initial value is randomly generated for the first node device, and the third initial value is randomly generated for the second node device. The paired encryption and decryption method as described in claim 1, wherein the control device, the first node device and the second node device are capable of performing hashing operations using a secure hash algorithm. The paired encryption and decryption method as described in claim 1, wherein the first node device uses the pre-shared key to encrypt a first node security information into a first encrypted information, and the first node security information includes the second initial value, a first timestamp and a first node ID. After the second node device uses the pre-shared key to decrypt the first encrypted information, the second node device further verifies whether the first timestamp is correct and verifies whether the first node ID is located in the ID list data. The paired encryption and decryption method as described in claim 1, wherein the first node device uses the joint key to encrypt a first node communication information into a third encrypted information, and the first node communication information includes the third hash value and a third timestamp. After the second node device uses the joint key to decrypt the third encrypted information, the second node device further verifies whether the third timestamp is correct. A paired encryption and decryption method as described in claim 1, wherein the first node device uses the pre-shared key to encrypt a second node security information into a second encrypted information, and the second node security information includes the third initial value, a second timestamp and a second node ID. After the first node device uses the pre-shared key to decrypt the second encrypted information, the second node device further verifies whether the second timestamp is correct and verifies whether the second node ID is located in the ID list data.

Images