Cloud end and side end communication encryption method based on PUF fingerprints

Abstract

The invention provides a cloud end and side end communication encryption method based on PUF fingerprints, and belongs to the field of communication encryption algorithm design and physical unclonable functions. A response signal R in the CRP relation of the PUF stored in the cloud is used as a secret key, a plaintext is encrypted, a ciphertext is obtained, a challenge signal C correspondingly input by the R is used as a secret key mask and is transmitted in a channel together with the ciphertext, and after receiving the ciphertext and the secret key mask C, an edge device inputs the C to a PUF module of the edge device, and the C is transmitted to the PUF module of the edge device. A corresponding output challenge R, namely a secret key, is obtained through a physical mechanism and circuit design in the PUF, and finally, the secret key is used for decrypting the ciphertext to obtain correct plaintext data. According to the method, the capacity of flexible key configuration is effectively supported through the CRP pre-stored in the cloud, and only the ciphertext and the key mask are transmitted at the same time in the whole communication process, so that the security risk caused by eavesdropping attack is avoided, and the throughput of encryption and decryption is improved; and the PUF module is simultaneously used for identity verification and communication data encryption, so that the hardware and power consumption cost is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of communication encryption algorithm design and physical unclonable function, and in particular to a high-security and lightweight cloud-to-edge communication encryption method design based on a physical unclonable function (PUF) fingerprint as a key mask and a key. Background Art

[0002] The widespread application and rapid growth of edge devices in smart cities, national defense security, smart homes and other fields have brought a large amount of data interaction from the cloud to the edge. These edge devices need to frequently send sensitive data to the cloud where important privacy information is stored, including sensor data, user privacy content, commercial confidential data, etc. The cloud also needs to send data information to edge devices. Therefore, the cloud needs to communicate securely with the edge while verifying the legitimacy of the edge device to avoid potential security risks such as identity fraud attacks and channel monitoring attacks.

[0003] Therefore, it is necessary to give the device a unique identifier for identity authentication under the limitations of hardware overhead such as computing power, power consumption, and area on the edge device to avoid possible fraud attacks on the cloud; at the same time, the data transmitted on the cloud-edge communication channel is encrypted and protected to prevent data leakage caused by eavesdropping attacks.

[0004] Physical Unclonable Function (PUF) is widely regarded as a hardware security primitive. It uses the process fluctuations of device preparation or the physical random mechanism in the working process as an unpredictable hardware fingerprint, providing a lightweight authentication solution for devices deployed in unsupervised environments. As a physical entity, PUF can perform undetectable black-box processing on a given input (Challenge signal Challenge, referred to as C) and transform it into an output (Response signal Response, referred to as R). This operation is determined by the physical mechanism and circuit design inside the PUF. The mapping relationship between its input and output signals, namely the Challenge-Response Pair (CRP), can be used as a hardware fingerprint for the legitimate authentication of the device.

[0005] In order to avoid the risk of data being eavesdropped and leaked during the communication process, the original plaintext data needs to be encrypted. In order to avoid transmitting the ciphertext and the corresponding key in the channel at the same time, asymmetric encryption algorithms are generally used instead of symmetric encryption schemes, including the use of RSA algorithms, elliptic curve cryptography (ECC) and other schemes. However, these algorithms involve complex mathematical calculation operations such as number theory, including exponentiation and modulus of large numbers, and require special encryption and decryption modules, which bring additional power consumption and area costs, and the encryption and decryption delay is relatively high, affecting the throughput of communication data. Therefore, the safe and low-cost implementation of encryption protection for transmitted data is of great significance for edge devices to resist eavesdropping attacks and avoid data leakage and other security risks. Summary of the invention

[0006] In response to the problems existing in the above prior art, the present invention proposes to use the mapping relationship of the input-output signal of PUF as the encryption strategy of the key mask and key, and realize the secure transmission of ciphertext and key in the cloud-edge channel with extremely low hardware cost. The present invention is the first to use the challenge-response pair CRP of PUF for security scenarios other than identity authentication, and replaces the expensive encryption and decryption modules with a single module. It has the ability to resist security risks such as identity attacks and eavesdropping attacks at the same time, and significantly optimizes its deployment area and power consumption at the edge.

[0007] The technical solution of the present invention is as follows:

[0008] A method for data encryption transmission based on a challenge-response pair relationship of a physical unclonable function (PUF), characterized in that, when data interaction and communication are performed between the cloud and the edge, a response signal R in a CRP relationship of a physical unclonable function stored in the cloud is used as a key for encrypting plaintext, and a challenge signal C corresponding to the input of R is used as a security mask of the key; when data needs to be transmitted, some C and corresponding R in the CRP relationship are selected, and these Rs are combined until the length of the key reaches the requirement, and the corresponding Cs are also arranged in the order of R; R is used as a key to encrypt the plaintext to obtain a ciphertext; and C corresponding to R is used as a key mask and transmitted together with the ciphertext in an insecure channel; after the edge device receives the ciphertext and the key mask, the key mask C is input into its PUF module, and the corresponding output challenge R, that is, the key used for encryption, is obtained by the physical mechanism and circuit design inside the PUF; finally, the ciphertext is decrypted using the key to obtain the correct plaintext data; during the entire communication process, only the ciphertext and the key mask are transmitted simultaneously, and the key corresponding to the ciphertext is not directly transmitted, thereby avoiding the security risks brought by eavesdropping attacks.

[0009] Furthermore, in the above-mentioned method of encrypting and transmitting data based on the challenge-response relationship of the physical unclonable function (PUF), before the cloud-edge data interaction, the cloud will first detect whether the CRP relationship of the edge PUF is consistent with the information of the CRP library stored in the cloud to complete the identification and verification of the hardware identity. Only after the CRP relationship consistency verification is passed, the cloud will send the encrypted data and key mask to the edge device. This verification process can not only identify the legitimate identity of the communicator and avoid excessive leakage of ciphertext information, but also ensure that the PUF module corresponding to the edge device that receives the ciphertext and key mask matches the PUF identity recorded in the cloud, effectively avoiding obtaining incorrect content after decryption at the edge.

[0010] Furthermore, in the above-mentioned method for encrypting and transmitting data based on a challenge-response relationship of a physical unclonable function (PUF), the physical unclonable function module can be an SRAM PUF, an arbiter PUF, a butterfly PUF, a ring oscillator PUF, etc. based on CMOS devices and their derived circuit designs, or it can be an RRAM PUF, an MRAM PUF, a FeFET PUF, etc. based on emerging non-volatile NVM devices.

[0011] Furthermore, the above-mentioned method for encrypting and transmitting data based on the challenge-response relationship of the physical unclonable function (PUF), the method of encrypting the plain text using the response signal R as a key includes digital domain encryption schemes such as XOR encryption and XOR encryption, or using analog quantities to perform more complex mathematical operations is also included in the design concept of the present invention.

[0012] Furthermore, in the above-mentioned method of encrypting and transmitting data based on the challenge-response relationship of the physical unclonable function (PUF), when the edge sends encrypted data to the cloud, the PUF module of the edge hardware generates CRP, and uses it as the encryption key and key mask to transmit data to the cloud respectively. After the cloud receives the ciphertext and the key mask, it uses the CRP library stored in the cloud to obtain the key corresponding to the key mask, and finally uses the key to decrypt the ciphertext to obtain the correct plaintext data.

[0013] The present invention implements for the first time a secure masking strategy based on the PUF CRP relationship as the key for data communication, which simultaneously realizes the identity authentication requirements and data confidentiality transmission requirements between the cloud and the edge with almost no additional hardware and power consumption, avoiding security risks such as possible identity attacks and theft attacks on edge devices. Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention reuses the functions of the PUF module, which can be used as a security hardware module for identity authentication and an encryption module for communication data protection. The multiplexing avoids the hardware and power consumption costs of introducing other encryption schemes, improves security, and significantly reduces the difficulty of deploying these requirements at the edge, avoiding the use of more expensive asymmetric encryption algorithms.

[0015] 2. The data protection method of the present invention utilizes the CRP information collected during cloud registration, and supports arbitrary modification and flexible configuration of key masks in the cloud, because a PUF has a large number of CRPs that can be used for verification and encryption protection. For the same key (response signal), there can be different key masks (challenge signals), and there is no weakness in the symmetric encryption algorithm that requires the key to be announced and broadcast in advance. The ability to flexibly configure keys is effectively supported by the CRP pre-stored in the cloud.

[0016] 3. The key masking scheme of the present invention significantly improves the throughput of encryption and decryption and reduces the required delay cost. In traditional asymmetric algorithms, special modules are required for mathematical operations, which has significant time overhead and reduces the throughput of data transmission. The present invention uses the ability of PUF to generate CRP at high speed to achieve a more efficient masking scheme, avoiding the impact of encryption operations on data transmission speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the possible eavesdropping attack risks faced by the cloud-edge communication channel;

[0018] Figure 2 It is a flow chart of secure communication based on asymmetric encryption algorithm;

[0019] Figure 3 This is a schematic diagram of the secure communication based on PUF fingerprint as a key mask proposed by the present invention;

[0020] Figure 4 A schematic diagram of using a PUF fingerprint as an encrypted key mask according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further clearly and completely described below by specific embodiments in conjunction with the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0022] Figure 1The article shows the security risks of data theft that hardware devices at the edge may face when communicating and transmitting data with the cloud. Attackers may eavesdrop on the content transmitted in the channel directly, so it is necessary to encrypt the information in this process. Due to the limitations of symmetric encryption in key distribution, asymmetric encryption solutions are generally used in actual use to avoid transmitting private keys in the channel. Figure 2 As shown in the figure, Alice and Bob, who are communicating with each other, each have a different private key, which is generated locally by themselves and does not need to be shared with each other. However, they have a common public key, which is used to encrypt data, and only the private key can decrypt the correct information. Therefore, even if the attacker obtains the public key and ciphertext, it cannot be decrypted because the private key is not public, ensuring the security of communication. However, asymmetric encryption algorithms generally require additional encryption and decryption modules, involving exponentiation and modular operations, and the hardware cost and time cost are relatively higher.

[0023] Figure 3 The present invention proposes a solution for secure and lightweight symmetric encryption based on PUF's CRP as a key mask and key. CRP is the explicit fingerprint of PUF. The cloud can send a challenge C to PUF and question its output response R to compare whether the relationship between CR is consistent with the content in the CRP library registered in the cloud. If the degree of match exceeds a certain level (such as 98%), the PUF is considered legal. Therefore, the PUF that has gone through the registration stage will retain a part of its CRP relationship in the cloud for subsequent identity authentication, making the key mask scheme of the present invention feasible.

[0024] When the cloud needs to send information to an edge device with a specific identity, it will first determine the PUF number corresponding to the device and index the corresponding CRP relationship in the CRP library, and send a small number of C to the device and compare the R returned by the PUF to perform the aforementioned identity authentication process. When the identity authentication is passed, the cloud will randomly select C and the corresponding R from the CRP library. In general PUF designs, C and R are both binary, with C being multi-bit and R being single-bit. Therefore, R can be used as an encryption key, and the corresponding C is a key mask that is difficult for a third party to crack. If the CRP relationship of the PUF is unknown, the corresponding key R cannot be derived from C. Figure 3 The embodiment of shows a scheme of XOR encryption of plaintext with a single-bit key. At this time, the content transmitted in the channel is only the ciphertext and the key mask C. When the edge device receives the ciphertext, it will input the obtained key mask C as the challenge of PUF, and use the PUF circuit to obtain the corresponding output R, which can turn the key mask into a real key. After that, the XOR operation is used to decrypt to get the correct plaintext.

[0025] Since PUF is collision-resistant and unique, the CRP relationships of different PUFs are different and unpredictable. Since the cloud has recorded the CRP relationship of a specific PUF during the registration process, and the edge PUF has its own ability to generate an output response R based on the input challenge C, only the cloud and edge devices can obtain the CRP mapping relationship during the entire communication process. This ensures that the key mask C can only be compiled into the key R by the cloud and the corresponding PUF, and cannot be cracked by a third party.

[0026] Figure 3 An implementation example of the CRP key mask secure communication scheme proposed in Figure 4 As shown. In general, the key required is multi-bit, and different key bits are responsible for encrypting different parts of the plaintext. Therefore, in actual communication, the cloud will randomly select multiple CRP entries from the CRP library and combine these R until the key length meets the requirement. The corresponding C will also be arranged in the order of R. The plaintext is then encrypted with the key to obtain the ciphertext, and the mask C (that is, the corresponding challenge) and the ciphertext are sent to the edge together. Figure 4 The process is not only applicable to data communication from the cloud to the edge, but also to the scenario where the edge sends data to the cloud. At this time, the PUF module of the edge hardware generates CRP and uses it as the encryption key and key mask respectively to securely transmit data to the cloud. After the cloud receives the ciphertext and key mask, it uses the CRP library stored in the cloud to obtain the key corresponding to the key mask, and finally uses the key to decrypt the ciphertext to obtain the correct plaintext data. In actual encryption scenarios, lightweight XOR and XOR encryption schemes can be used, that is, plaintext and key XOR / XOR to obtain ciphertext; at this time, the receiver only needs to XOR / XOR the ciphertext and key to obtain plaintext. The method proposed in the present invention can also support more complex digital encryption schemes, because its core is the protection of key information. Thanks to the advantages of symmetric encryption, this encryption method has low latency, high throughput, and less edge resource usage, especially the reuse of PUF modules avoids additional hardware costs.

[0027] This embodiment fully and in detail describes a secure and low-cost lightweight data encryption transmission scheme based on the challenge-response relationship of a physical unclonable function, using the challenge signal as a key mask to avoid the security issues of symmetric encryption schemes for data transmission, while effectively avoiding the huge overhead of asymmetric encryption algorithms deployed on edge hardware. Compared with other encryption strategies, it does not require additional encryption and decryption modules, and has lower hardware costs and better security.

[0028] Finally, it should be noted that the purpose of publishing the embodiments is to help further understand the present invention, but those skilled in the art can understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection claimed by the present invention shall be subject to the scope defined in the claims.

Claims

1. A method for encrypting and transmitting data based on a challenge-response pair relationship of a physically unclonable function PUF, characterized in that: When data is interacting and communicating between the cloud and the edge, the response signal R in the CRP relationship of the physical unclonable function stored in the cloud is used as the key for encrypting the plaintext, and the challenge signal C corresponding to the input of R is used as the security mask of the key; When data needs to be transmitted, select some C and corresponding R in the CRP relationship, and combine these Rs until the key length reaches the requirement, and the corresponding C will be arranged in the order of R; R is used as the key to encrypt the plaintext to obtain the ciphertext; and the C corresponding to R is used as the key mask and transmitted together with the ciphertext in an insecure channel; after the edge device receives the ciphertext and key mask, it will input the key mask C into its PUF module, and the corresponding output challenge R, which is the key used for encryption, will be obtained by the physical mechanism and circuit design inside the PUF; finally, the ciphertext is decrypted using the key to obtain the correct plaintext data; during the entire communication process, only the ciphertext and key mask will be transmitted simultaneously, and the key corresponding to the ciphertext will not be directly transmitted, avoiding the security risks brought by eavesdropping attacks.

2. The method for encrypting and transmitting data based on a challenge-response pair relationship of a physical unclonable function PUF as claimed in claim 1, characterized in that: Before data interaction between the cloud and the edge, the cloud will first detect whether the CRP relationship of the edge PUF is consistent with the information in the CRP library stored in the cloud to complete the identification and verification of the hardware identity; only after the CRP relationship consistency verification is passed, the cloud will send encrypted data and key mask to the edge device.

3. The method for encrypting and transmitting data based on a challenge-response pair relationship of a physical unclonable function PUF as claimed in claim 1, characterized in that: The physical unclonable function module is: SRAM PUF, arbiter PUF, butterfly PUF or ring oscillator PUF based on CMOS devices, and RRAM PUF, MRAM PUF or FeFET PUF based on emerging non-volatile NVM devices.

4. The method for encrypting and transmitting data based on a challenge-response pair relationship of a physical unclonable function PUF as claimed in claim 1, characterized in that: The method of using the response signal R as a key to encrypt the plain text includes XOR encryption, XOR encryption, digital domain encryption, or more complex mathematical operation encryption using analog quantities.

5. The method for encrypting and transmitting data based on a challenge-response pair relationship of a physical unclonable function PUF as claimed in claim 1, characterized in that: When the edge sends encrypted data to the cloud, the PUF module of the edge hardware generates CRP and uses it as the encryption key and key mask to transmit data to the cloud. After the cloud receives the ciphertext and key mask, it uses the CRP library stored in the cloud to obtain the key corresponding to the key mask. Finally, the ciphertext is decrypted using the key to obtain the correct plaintext data.

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