Radio frequency fingerprint enhancement circuit based on physical unclonable function digital security engine

Abstract

The invention discloses a radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine. The radio frequency fingerprint enhancement circuit comprises a digital security engine module, an all-digital phase-locked loop module and a two-point modulation module, the digital security engine module is used for enhancing the difference of carrier frequency offset between the oscillators in different all-digital phase-locked loop modules and expanding the range of recognizable carrier frequency; the two-point modulation module is used for compensating the high-frequency information filtered by the all-digital phase-locked loop module, so that the output end of the oscillator recovers complete modulation information; and the all-digital phase-locked loop module is used for generating a carrier frequency required by signal transmission of the transmitting end. According to the embodiment of the invention, through mutual cooperation of the modules, the digital security engine module is used for enhancing the difference of carrier frequency offset between different oscillators and expanding the range of recognizable carrier frequency offset, so that the recognition overhead of a receiving end is reduced, and the recognition accuracy is improved.

Description

Technical Field

[0001] The invention belongs to the field of physical layer security, and in particular relates to a radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine. Background Art

[0002] With the continuous increase in the scale and equipment of wireless communications, the communication rate and energy efficiency have been significantly improved, but wireless security has seriously lagged behind the development of communications. In particular, IoT nodes with limited resources and computing power are more vulnerable to hacker attacks, which seriously affects the privacy of user information and hinders the development of wireless communications.

[0003] Traditionally, wireless communications are completely protected by public key-based cryptography. However, most IoT nodes lack the energy and storage resources required to implement advanced cryptographic algorithms, and the wireless device authentication mechanism and authentication protocol itself have security vulnerabilities. Furthermore, the enemy can illegally obtain encryption keys stored in non-volatile memory or SRAM by means of invasive, semi-invasive, side channel, and software attacks, threatening information security. To this end, in order to reduce the overhead of key generation and storage, a physical unclonable function was developed that uses the device's own physical deviation as a unique key. Although the physical unclonable function is unclonable and does not directly store the key in the digital domain, the extracted key is still used in digital cryptography and will be transmitted in the channel, so it is still vulnerable to digital cloning attacks by imposters.

[0004] The unique hardware defects of wireless chips are called radio frequency fingerprints. Radio frequency fingerprint recognition technology based on the physical layer characteristics of signals can realize individual recognition of communication radiation sources without relying on traditional keys. It is a key technology for physical layer security and has the advantages of high recognition accuracy and strong security. Therefore, it is of great significance to design and research physical layer security recognition circuits that enhance the deviation of radio frequency fingerprints and improve the recognition accuracy. Summary of the invention

[0005] The technical problem to be solved by the present invention is that, due to various deficiencies in existing wireless security protection devices, the present invention provides a radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine, including: a digital security engine module, a full digital phase-locked loop module, and a two-point modulation module;

[0007] The digital security engine module is used to enhance the difference in carrier frequency offset between oscillators in different all-digital phase-locked loop modules and expand the range of identifiable carrier frequencies, the input end is connected to the decimal part of the external input carrier frequency control word, and the output end is connected to the all-digital phase-locked loop module;

[0008] The two-point modulation module is used to compensate for the high-frequency information filtered by the full digital phase-locked loop module, so that the output end of the oscillator restores the complete modulation information, and the output end is connected to the digital security engine module and the full digital phase-locked loop module;

[0009] The all-digital phase-locked loop module is used to generate the carrier frequency required for transmitting the signal at the transmitting end.

[0010] Preferably, the digital security engine module comprises: a physical unclonable unit and a first adder;

[0011] The physical unclonable unit input and the first adder input are connected to the decimal part of the external input carrier frequency control word; the physical unclonable unit output and the two-point modulation module output are connected to the first adder input; and the first adder output is connected to the fully digital phase-locked loop module.

[0012] Preferably, the input of the physical unclonable unit is combined with Bluetooth frequency hopping communication, and authentication is performed at multiple frequencies.

[0013] Preferably, the physical unclonable unit output signal is converted from a digital output to an analog output based on a carrier frequency offset.

[0014] Preferably, the all-digital phase-locked loop module comprises: a modulator, a fractional frequency divider, a time-to-digital converter, a digital filter, an oscillator, a second adder and a third adder;

[0015] The modulator input is connected to the fractional frequency divider output and the first adder output; the modulator output and the integer part of the external input carrier frequency control word are connected to the second adder input; the second adder output and the oscillator output are connected to the fractional frequency divider input; the fractional frequency divider output is also connected to the time digital converter input; the time digital converter output is connected to the digital filter input; the digital filter output and the two-point modulation module output are connected to the third adder input; the third adder output is connected to the oscillator input; the oscillator output is used to output the carrier frequency required for the transmitter signal transmission.

[0016] Preferably, the time-to-digital converter input terminal is also connected to an external reference clock signal.

[0017] Preferably, the two-point modulation module comprises: a high-pass path unit and a low-pass path unit;

[0018] The output terminal of the low-pass path unit is connected to the input terminal of the first adder; the output terminal of the high-pass path unit is connected to the input terminal of the third adder;

[0019] Among them, after the output signal of the low-pass path unit enters the fully digital phase-locked loop module, the frequency components higher than the loop bandwidth will be filtered out; after the output signal of the high-pass path unit enters the fully digital phase-locked loop module, the filtered high-frequency information will be compensated.

[0020] Preferably, the high-pass path unit comprises: a digital-to-analog converter and a high-pass filter;

[0021] The output end of the digital-to-analog converter is connected to the input end of the high-pass filter; the output end of the high-pass filter is connected to the input end of the third adder.

[0022] Preferably, it further comprises a receiving module; the receiving module is provided with a non-volatile memory; the receiving module is used to store the digital output of the physical non-clonable unit in the non-volatile memory under initialization conditions.

[0023] Implementing the embodiments of the present invention has the following beneficial effects:

[0024] (1) The embodiments of the present invention use the modules to cooperate with each other and utilize the digital security engine module to enhance the difference in carrier frequency offsets between different oscillators and expand the range of identifiable carrier frequency offsets, thereby reducing the overhead of receiving end identification and improving the accuracy of identification.

[0025] (2) The embodiment of the present invention uses a physical unclonable unit as the core of the digital security engine module to generate uniform and random digital output, thereby improving the uniqueness and uniformity of the radio frequency fingerprint, and the additional overhead is very small. In addition, the physical unclonable unit is not replicable in terms of process, so that even if the other party knows the structure, it is impossible to manufacture the same device for impersonation, thereby enhancing the security of the transceiver.

[0026] (3) The embodiment of the present invention combines the input of a physical unclonable unit with Bluetooth frequency hopping communication, performs authentication at multiple frequency points, and adopts a majority voting strategy, thereby significantly reducing the probability of identical RF fingerprints and increasing the difficulty of fingerprint feature forgery.

[0027] (4) The embodiment of the present invention adopts a physical unclonable unit to output an analog signal of carrier frequency offset instead of directly outputting a digital signal, thereby avoiding the possibility of digital output of a physical unclonable function being intercepted when used directly for authentication, and further improving the security of the authentication process.

[0028] (5) In the embodiment of the present invention, a non-volatile memory is set on the receiving module so that the digital output of the physical non-clonable unit is safely stored in the non-volatile memory of the receiving module under initialization conditions. After the device identification is completed, the corresponding output is called to reduce the difficulty of carrier frequency offset estimation and recovery, thereby reducing the overhead of receiver resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A radio frequency fingerprint enhancement circuit architecture diagram based on a physical unclonable function digital security engine is provided for the implementation of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the present embodiment discloses a radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine, and the radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine includes: a digital security engine module (Digital Security Engine) 10, an all-digital phase-locked loop module (ADPLL) 20 and a two-point modulation module. The input end of the digital security engine module 10 is connected to the decimal part of the external input carrier frequency control word (FCW, frac )). The output end of the digital security engine module 10 is connected to the input end of the full digital phase-locked loop module 20. The output end of the two-point modulation module is connected to the input end of the digital security engine module 10 and the input end of the full digital phase-locked loop module 20. The output end of the full digital phase-locked loop module 20 is used to output the carrier frequency required for the signal transmission of the transmitter, and is connected to the input end of the driver power amplifier (Driver Power Amplifier, DPA) module. The driver power amplifier module is used to output the transmission signal.

[0033] Among them, the digital security engine module 10 is used to enhance the difference in carrier frequency offset between oscillators 207 in different all-digital phase-locked loop modules 20 and expand the range of identifiable carrier frequencies. The two-point modulation module is used to compensate for the high-frequency information filtered by the all-digital phase-locked loop module 20, so that the output end of the oscillator 207 can restore the complete modulation information. The all-digital phase-locked loop module 20 is used to generate the carrier frequency required for the transmitter signal transmission. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine uses the digital security engine module 10 to enhance the difference in carrier frequency offset between different oscillators 207 and expand the range of identifiable carrier frequency offsets by using the modules to cooperate with each other, thereby reducing the overhead of the receiving end identification and improving the accuracy of identification.

[0034] Specifically, the digital security engine module 10 includes a physical unclonable unit 101 and a first adder 102. The input end of the physical unclonable unit 101 and the input end of the first adder 102 are connected to the fractional part of the external input carrier frequency control word. The output end of the physical unclonable unit 101 and the output end of the two-point modulation module are connected to the input end of the first adder 102. The output end of the first adder is connected to the input end of the full digital phase-locked loop module 20, and is used to add the output signal of the physical unclonable unit 101, the fractional part of the external input carrier frequency control word and the output signal of the two-point modulation module, and input them into the full digital phase-locked loop module 20.

[0035] The digital security engine module 10 uses a physical unclonable unit 101 as the core of the digital security engine module 10 to generate uniform and random digital outputs, thereby improving the uniqueness and uniformity of the radio frequency fingerprint. In addition, the physical unclonable unit 101 has very little additional overhead and low energy consumption, which meets the requirements of green development. In addition, the physical unclonable unit 101 is not replicable in terms of process, so that the other party cannot manufacture the same device for impersonation even if the structure is known, thereby enhancing the security of the transceiver. The output signal of the physical unclonable unit 101 is converted from a digital output to an analog output based on a carrier frequency offset. Instead of directly outputting a digital signal, the possibility of interception of the digital output of the physical unclonable function directly used for authentication is avoided, further improving the security of the authentication process. The input of the physical unclonable unit 101 is combined with Bluetooth frequency hopping communication, and authentication is performed at multiple frequency points before output. In addition, a majority voting strategy is adopted, thereby significantly reducing the probability of identical radio frequency fingerprints and increasing the difficulty of fingerprint feature forgery.

[0036] The all-digital phase-locked loop module includes: a modulator 201, a fractional frequency divider 203, a time-to-digital converter 204, a digital filter 205, an oscillator 207, a second adder 202 and a third adder 206. The input end of the modulator 201 is connected to the output end of the fractional frequency divider 203 and the output end of the first adder 102. The output end of the modulator 201 and the integer part of the external input carrier frequency control word (FCW ，int ) is connected to the input end of the second adder 202. The output end of the second adder 202 and the output end of the oscillator 207 are connected to the input end of the fractional divider 203. The output end of the fractional divider 203 is also connected to the input end of the time digital converter 204. The output end of the time digital converter 204 is connected to the input end of the digital filter 205. The output end of the digital filter 205 and the output end of the two-point modulation module are connected to the input end of the third adder 206. The output end of the third adder 206 is connected to the input end of the oscillator 207. The output end of the oscillator 207 is used to output the carrier frequency required for the signal transmission of the transmitter, and is connected to the input end of the driving power amplifier module. The input end of the time digital converter 204 is also connected to the external reference clock signal, which is used to receive the external reference clock signal (CK,in) and convert it into an output signal.

[0037] The two-point modulation module includes: a high-pass path unit 320 and a low-pass path unit 310. The output end of the low-pass path unit 310 is connected to the input end of the first adder 102. The output end of the high-pass path unit 320 is connected to the input end of the third adder 206.

[0038] Among them, after the output signal of the low-pass path unit 310 enters the full digital phase-locked loop module, the phase information of the output signal reaches the input end of the oscillator 207 through the modulator 201, the fractional frequency divider 203, the time-to-digital converter 204, the digital filter 205 and the third adder 206 in sequence, and the frequency components higher than the loop bandwidth will be filtered out. After the output signal of the high-pass path unit 320 enters the full digital phase-locked loop module 20, the filtered high-frequency information will be compensated.

[0039] Specifically, the high-pass path unit 320 includes: a digital-to-analog converter 321 and a high-pass filter 322. The output end of the digital-to-analog converter 321 is connected to the input end of the high-pass filter 322. The output end of the high-pass filter 322 is connected to the input end of the third adder 206. The phase information of the output signal of the high-pass path unit 320 directly controls the output frequency of the oscillator 207 through the digital-to-analog converter 321 and the high-pass filter 322. On this path, it can be regarded as the noise of the oscillator 207. After passing through the loop, it reaches the output end and presents a high-pass characteristic, and selects appropriate gains for the high-pass path unit 320 and the low-pass path unit 310 respectively. The high-frequency component of the high-pass path unit 320 reaching the output end of the oscillator 207 can just compensate for the lost high-frequency information of the low-pass path unit 320 reaching the output end of the oscillator 207, thereby realizing that the transfer function of the modulated signal reaching the output end of the oscillator 207 presents an all-pass characteristic.

[0040] The RF fingerprint enhancement circuit based on the physical unclonable function digital security engine also includes a receiving module (not shown). The receiving module is arranged on the receiver. The transmission signal output by the driving power amplifier module will be received by the receiver. The receiving module is provided with a non-volatile memory. The receiving module is used to store the digital output of the physical unclonable unit in the non-volatile memory under the initialization condition. The RF fingerprint enhancement circuit based on the physical unclonable function digital security engine sets a non-volatile memory on the receiving module, so that the digital output of the physical unclonable unit is safely stored in the non-volatile memory of the receiving module under the initialization condition, and the corresponding output is called after the device identification is completed to reduce the difficulty of carrier frequency offset estimation and recovery, thereby reducing the overhead of receiver resources.

[0041] In summary, the present invention sets modules with different functions to make the difference of carrier frequency offset between different oscillators in the radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine and expand the range of identifiable carrier frequency offset, thereby reducing the overhead of receiving end identification and improving the accuracy of identification. Then, the physical unclonable unit 101 is used as the core of the digital security engine module 10. By utilizing the various characteristics of the physical unclonable unit 101, the radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine has various advantages, realizing complete protection of wireless communication.

[0042] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A radio frequency fingerprint enhancement circuit based on a physical unclonable function digital security engine, characterized in that: include: Digital security engine module, full digital phase-locked loop module, two-point modulation module; The digital security engine module is used to enhance the difference in carrier frequency offset between oscillators in different all-digital phase-locked loop modules and expand the range of identifiable carrier frequencies, the input end is connected to the decimal part of the external input carrier frequency control word, and the output end is connected to the all-digital phase-locked loop module; The two-point modulation module is used to compensate for the high-frequency information filtered by the full digital phase-locked loop module, so that the output end of the oscillator restores the complete modulation information, and the output end is connected to the digital security engine module and the full digital phase-locked loop module; The fully digital phase-locked loop module is used to generate the carrier frequency required for transmitting the signal at the transmitting end.

2. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 1 is characterized in that: The digital security engine module includes: a physical unclonable unit and a first adder; The physical unclonable unit input and the first adder input are connected to the decimal part of the external input carrier frequency control word; the physical unclonable unit output and the two-point modulation module output are connected to the first adder input; and the first adder output is connected to the fully digital phase-locked loop module.

3. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 2 is characterized in that: The input of the physical unclonable unit is combined with Bluetooth frequency hopping communication and authentication is performed at multiple frequencies.

4. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 2 is characterized in that: The physical unclonable unit output signal is converted from a digital output to an analog output based on a carrier frequency offset.

5. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 2 is characterized in that: The all-digital phase-locked loop module includes: a modulator, a fractional frequency divider, a time-to-digital converter, a digital filter, an oscillator, a second adder and a third adder; The modulator input is connected to the fractional frequency divider output and the first adder output; the modulator output and the integer part of the external input carrier frequency control word are connected to the second adder input; the second adder output and the oscillator output are connected to the fractional frequency divider input; the fractional frequency divider output is also connected to the time digital converter input; the time digital converter output is connected to the digital filter input; the digital filter output and the two-point modulation module output are connected to the third adder input; the third adder output is connected to the oscillator input; the oscillator output is used to output the carrier frequency required for the transmitter signal transmission.

6. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 5 is characterized in that: The input terminal of the time-to-digital converter is also connected to an external reference clock signal.

7. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 5 is characterized in that: The two-point modulation module includes: a high-pass path unit and a low-pass path unit; The output terminal of the low-pass path unit is connected to the input terminal of the first adder; the output terminal of the high-pass path unit is connected to the input terminal of the third adder; Among them, after the output signal of the low-pass path unit enters the fully digital phase-locked loop module, the frequency components higher than the loop bandwidth will be filtered out; after the output signal of the high-pass path unit enters the fully digital phase-locked loop module, the filtered high-frequency information will be compensated.

8. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 7 is characterized in that: The high-pass path unit includes: a digital-to-analog converter and a high-pass filter; The output end of the digital-to-analog converter is connected to the input end of the high-pass filter; the output end of the high-pass filter is connected to the input end of the third adder.

9. The radio frequency fingerprint enhancement circuit based on the physical unclonable function digital security engine according to claim 2 is characterized in that: It also includes a receiving module; the receiving module is provided with a non-volatile memory; the receiving module is used to store the digital output of the physical non-clonable unit in the non-volatile memory under an initialization condition.

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