Radio frequency fingerprinting enhanced circuit based on physically unclonable function digital security engine

Abstract

The application discloses a radio frequency fingerprint enhancement circuit based on a physically unclonable function digital security engine, which comprises a digital security engine module, a full-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 offsets between different full-digital phase-locked loop modules and expanding the range of identifiable carrier frequency; the two-point modulation module is used for compensating high-frequency information filtered by the full-digital phase-locked loop module, so that the output end of the oscillator restores complete modulation information; and the full-digital phase-locked loop module is used for generating a carrier frequency required by a transmitting end signal to be transmitted. Through mutual cooperation of the modules, the digital security engine module is used for enhancing the difference of carrier frequency offsets between different oscillators and expanding the range of identifiable carrier frequency offsets, so that the cost of identification of a receiving end is reduced, and the accuracy of identification is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of physical layer security, and particularly relates to a radio frequency fingerprint enhanced circuit based on a physically unclonable function digital security engine. BACKGROUND

[0002] With the increasing scale of wireless communication and devices, the communication rate and energy efficiency are significantly improved, but the wireless security lags far behind the communication development, especially the Internet of Things 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 communication.

[0003] Traditionally, wireless communication is completely protected by public key-based encryption technology. However, most Internet of Things nodes lack the energy and storage resources required to implement advanced encryption algorithms, and the wireless device identity authentication mechanism and authentication protocol itself has security vulnerabilities. Further, the enemy uses invasive, semi-invasive, side channel, software attack and other means to illegally obtain the encryption key stored in the non-volatile memory or SRAM, threatening information security. Therefore, in order to reduce the overhead of key generation and storage, a physically unclonable function is developed, which uses the physical deviation of the device itself as a unique key. Although the physically unclonable function has unclonability, the key is not directly stored in the digital domain, but 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 impostors.

[0004] The unique hardware defects of a wireless chip are called radio frequency fingerprints. The radio frequency fingerprint identification technology based on the physical layer characteristics of signals can realize individual identification of communication radiation sources without relying on traditional keys, and is a key technology for physical layer security, which has the advantages of high identification accuracy and strong security. Therefore, it is of great significance to design and research a physical layer security identification circuit that enhances the deviation of the radio frequency fingerprint and improves the identification accuracy. SUMMARY

[0005] The technical problem to be solved by the application is that the existing wireless security protection devices have various deficiencies, and the application provides a radio frequency fingerprint enhanced circuit based on a physically unclonable function digital security engine.

[0006] In order to solve the above technical problems, the embodiment of the application provides a radio frequency fingerprint enhanced circuit based on a physically unclonable function digital security engine, which comprises a digital security engine module, a fully digital phase-locked loop module and a two-point modulation module.

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

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

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

[0010] Preferably, the digital security engine module comprises a physically unclonable function and a first adder.

[0011] The input end of the physically unclonable function and the input end of the first adder are connected with the decimal part of the external input carrier frequency control word, the output end of the physically unclonable function and the output end of the two-point modulation module are connected with the input end of the first adder, and the output end of the first adder is connected with the all-digital phase-locked loop module.

[0012] Preferably, the input of the physically unclonable function is combined with Bluetooth frequency hopping communication and is authenticated at multiple frequency points.

[0013] Preferably, the output signal of the physically unclonable function is converted from digital output to analog output based on carrier frequency offset.

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

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

[0016] Preferably, the input end of the time-to-digital converter is also connected with 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 end of the low-pass path unit is connected with the input end of the first adder, and the output end of the high-pass path unit is connected with the input end of the third adder.

[0019] Wherein, after the output signal of the low-pass path unit enters the all-digital phase-locked loop module, the frequency components higher than the loop bandwidth are filtered out; and after the output signal of the high-pass path unit enters the all-digital phase-locked loop module, the filtered high-frequency information is 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 with the input end of the high-pass filter, and the output end of the high-pass filter is connected with the input end of the third adder.

[0022] Preferably, the receiving module is further provided, and the receiving module is provided with a non-volatile memory; and the receiving module is used for storing the digital output of the physically unclonable unit in the initialization condition into the non-volatile memory.

[0023] The embodiment of the present application has the following beneficial effects:

[0024] (1) The embodiment of the present application uses the mutual cooperation of each module, uses the digital security engine module to enhance the difference between the carrier frequency offsets of different oscillators and expand the range of identifiable carrier frequency offsets, and further reduces the overhead of the receiving end identification and improves the identification accuracy.

[0025] (2) The embodiment of the present application uses the physically unclonable unit as the core of the digital security engine module to generate uniform and random digital output, improves the uniqueness and uniformity of the radio frequency fingerprint, and has very small additional overhead. In addition, the physically unclonable unit is not reproducible in the process, so that the other party cannot manufacture the same device for impersonation even if the structure is known, and the security of the transceiver is further enhanced.

[0026] (3) The embodiment of the present application combines the input of the physically unclonable unit with Bluetooth frequency hopping communication to perform authentication at multiple frequency points and adopts a majority voting strategy, and thus the probability of the same radio frequency fingerprint can be significantly reduced, and the difficulty of fingerprint feature forgery is increased.

[0027] (4) The embodiment of the present application uses the analog signal output by the physically unclonable unit to output the carrier frequency offset, instead of directly outputting the digital signal, which avoids the possibility of directly using the digital output of the physically unclonable function for authentication interception, and further improves the security in the authentication process.

[0028] (5)The embodiment of the present application sets a nonvolatile memory on the receiving module, so that the digital output of the physically unclonable unit is safely stored in the nonvolatile memory of the receiving module under the initialization condition, the difficulty of carrier frequency offset estimation and recovery is reduced after the device identification is completed, and the cost of the receiver resource is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0030] Figure 1 A radio frequency fingerprint enhancement circuit architecture based on a physically unclonable function digital security engine provided by the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] As shown in Figure 1 The radio frequency fingerprint enhancement circuit based on the physically unclonable function digital security engine disclosed by the present embodiment comprises a digital security engine module 10, an all-digital phase-locked loop module 20 and a two-point modulation module. The input end of the digital security engine module 10 is connected with the fractional part (FCW, frac ) of the external input carrier frequency control word. The output end of the digital security engine module 10 is connected with the input end of the all-digital phase-locked loop module 20. The output end of the two-point modulation module is connected with the input end of the digital security engine module 10 and the input end of the all-digital phase-locked loop module 20. The output end of the all-digital phase-locked loop module 20 is used to output the carrier frequency required for transmitting the transmitting end signal, and is connected with the input end of the driver power amplifier (DPA) module. The driver power amplifier module is used to output the transmitting signal.

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

[0034] Further, 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 with the decimal part of the externally 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 with the input end of the first adder 102. The output end of the first adder is connected with the input end of the all-digital phase-locked loop module 20, which is used to add the output signal of the physical unclonable unit 101, the decimal part of the externally input carrier frequency control word and the output signal of the two-point modulation module, and input into the all-digital phase-locked loop module 20.

[0035] The digital security engine module 10 uses the physical unclonable unit 101 as the core of the digital security engine module 10 to generate uniform and random digital output, thereby improving the uniqueness and uniformity of the radio frequency fingerprint. Moreover, the physical unclonable unit 101 has very small additional overhead and low energy consumption, which meets the requirements of green development. In addition, the physical unclonable unit 101 is not reproducible in process, so that the opponent 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 digital output to analog output based on carrier frequency offset. Instead of directly outputting digital signals, the possibility of intercepting the digital output of the physical unclonable function for authentication is avoided, thereby further improving the security in the authentication process. The input of the physical unclonable unit 101 is combined with the Bluetooth frequency hopping communication, and the authentication is performed at multiple frequency points, and then the output is performed. Moreover, the majority voting strategy is adopted, thereby significantly reducing the probability of the same radio frequency fingerprint and increasing the difficulty of fingerprint feature forgery.

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

[0037] The two-point modulation module comprises 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 with the input end of the first adder 102. The output end of the high-pass path unit 320 is connected with the input end of the third adder 206.

[0038] Wherein, the phase information of the output signal of the low-pass path unit 310 entering the all-digital phase-locked loop module is sequentially transmitted to the input end of the oscillator 207 through the modulator 201, the fractional divider 203, the time-to-digital converter 204, the digital filter 205 and the third adder 206, and the frequency components higher than the loop bandwidth are filtered out. The output signal of the high-pass path unit 320 entering the all-digital phase-locked loop module 20 will compensate for the high-frequency information filtered out.

[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. The noise of the oscillator 207 on this path is presented as a high-pass characteristic after the loop, and appropriate gains are selected 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 exactly compensate for the lost high-frequency information of the low-pass path unit 320 reaching the output end of the oscillator 207, thereby realizing the all-pass characteristic of the transmission function of the modulated signal reaching the output end of the oscillator 207.

[0040] The radio frequency fingerprint enhancement circuit based on the physically unclonable function digital security engine further comprises a receiving module (not shown). The receiving module is arranged on a receiver. The transmitting signal output by the driving power amplifier module is received by the receiver. The receiving module is provided with a non-volatile memory. The receiving module is used for storing the digital output of the physically unclonable unit in the initialization condition into the non-volatile memory. The radio frequency fingerprint enhancement circuit based on the physically unclonable function digital security engine safely stores the digital output of the physically unclonable unit in the initialization condition into the non-volatile memory of the receiving module by arranging a non-volatile memory on the receiving module, and reduces the difficulty of calling the corresponding output carrier frequency offset estimation and recovery after device identification, thereby reducing the resource overhead of the receiver.

[0041] In summary, the radio frequency fingerprint enhancement circuit based on the physically unclonable function digital security engine can distinguish the carrier frequency offset between different oscillators by arranging different functional modules, expand the range of identifiable carrier frequency offset, reduce the overhead of the receiving end identification, and improve the accuracy of identification. The physically unclonable unit 101 is used as the core of the digital security engine module 10. Various characteristics of the physically unclonable unit 101 are used to make the radio frequency fingerprint enhancement circuit based on the physically unclonable function digital security engine have various advantages, and completely protect wireless communication.

[0042] The above only discloses one preferred embodiment of the present application, and of course cannot limit the scope of the present application. Those skilled in the art can understand that the above-mentioned embodiment can be implemented in whole or in part, and equivalent changes made according to the claims of the present application still fall within the scope of the present application.

Claims

1. A radio frequency fingerprinting enhanced circuit based on a physically unclonable function digital security engine, characterized by, The application relates to a digital security engine module, a full-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 offsets between oscillators in different full-digital phase-locked loop modules and expanding the range of identifiable carrier frequencies; the input end of the digital security engine module is connected with an external input carrier frequency and is used for receiving a decimal part of a carrier frequency control word; and the output end is connected with the full-digital phase-locked loop module. The two-point modulation module is used for compensating high-frequency information filtered by the full-digital phase-locked loop module, so that the output end of the oscillator restores complete modulation information; the output end of the two-point modulation module is connected with the digital security engine module and the full-digital phase-locked loop module. The full-digital phase-locked loop module is used for generating a carrier frequency required by a transmitting end signal. The digital security engine module comprises a physically unclonable unit and a first adder. The input end of the physically unclonable unit and the input end of the first adder are connected with a decimal part of an external input carrier frequency control word; the output end of the physically unclonable unit and the output end of the two-point modulation module are connected with the input end of the first adder; and the output end of the first adder is connected with the full-digital phase-locked loop module. The full-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. The input end of the modulator is connected with the output end of the fractional frequency divider and the output end of the first adder; the output end of the modulator and an integer part of an external input carrier frequency control word are connected with the input end of the second adder; the output end of the second adder and the output end of the oscillator are connected with the input end of the fractional frequency divider; the output end of the fractional frequency divider is also connected with the input end of the time-to-digital converter; the output end of the time-to-digital converter is connected with the input end of the digital filter; the output end of the digital filter and the output end of the two-point modulation module are connected with the input end of the third adder; the output end of the third adder is connected with the input end of the oscillator; and the output end of the oscillator is used for outputting a carrier frequency required by a transmitting end signal. The two-point modulation module comprises a high-pass path unit and a low-pass path unit. The output end of the low-pass path unit is connected with the input end of the first adder; and the output end of the high-pass path unit is connected with the input end of the third adder. After the output signal of the low-pass path unit enters the full-digital phase-locked loop module, frequency components higher than the loop bandwidth are filtered out; and after the output signal of the high-pass path unit enters the full-digital phase-locked loop module, the filtered high-frequency information is compensated. The input of the physically unclonable unit is combined with Bluetooth frequency hopping communication and is authenticated at multiple frequency points.

2. The RF fingerprinting enhanced circuit based on physically unclonable function digital security engine of claim 1, wherein, The output signal of the physically unclonable unit is converted from a digital output into an analog output based on carrier frequency offsets.

3. The RF fingerprinting enhanced circuit based on physically unclonable function digital security engine of claim 1, wherein, The input end of the time-to-digital converter is also connected with an external reference clock signal.

4. The Physical Unclonable Function based digital security engine radio frequency fingerprint enhancement circuit of claim 1, wherein, The high-pass path unit comprises a digital-to-analog converter and a high-pass filter.

5. The RF fingerprinting enhanced circuit based on physically unclonable function digital security engine of claim 1, wherein, ​ The digital-analog converter output end is connected with a high-pass filter input end; the high-pass filter output end is connected with a third adder input end.

6. The Physical Unclonable Function-based digital security engine radio frequency fingerprint enhancement circuit of claim 1, wherein, Further comprising a receiving module; the receiving module is provided with a non-volatile memory; the receiving module is used for storing the digital output of the physically unclonable function under the initialization condition into the non-volatile memory.

Images