Chaotic sequence pilot-based electro-optical modulation digital watermark transmission method and system

Abstract

The application discloses an electro-optical modulation digital watermark transmission method and system based on a chaos sequence pilot, and belongs to the technical field of safe optical communication. The method comprises the following steps: a sending end takes a chaos signal as a pilot signal controlled by a bias point of an electro-optical modulator, realizes embedding of the chaos signal into a sending signal, and obtains a digital watermark signal; wherein the electro-optical modulator is used for modulating the sending signal onto an optical carrier; the sending end sends the digital watermark signal to a receiving end, the receiving end performs correlation detection on the received signal and the chaos signal, and obtains a watermark sequence in the digital watermark signal. The application can realize embedding of watermark sequence information without affecting the complexity of an optical communication system, can realize watermark detection by only using simple correlation detection, realizes authentication of equipment, has the advantages of stronger robustness and long-term stability, and provides a new idea for optical communication physical layer identity authentication.

Description

Technical Field

[0001] This invention belongs to the field of secure optical communication technology, and more specifically, relates to an electro-optic modulation digital watermarking transmission method and system based on chaotic sequence pilots. Background Technology

[0002] Optical communication systems are widely used in modern society, and their security is a significant concern. Various problems can occur in optical communication systems, such as physical layer device attacks, identity spoofing, eavesdropping, and communication interception. Therefore, information security technology, key security technology, and identity security technology have been proposed to improve the security of optical communication systems.

[0003] Compared with traditional upper-layer security algorithms and protocols, physical layer authentication technology has some unique advantages, such as: physical layer security mechanisms can solve communication security problems at the "signal level" and are an effective supplement to traditional security mechanisms; and physical layer security mechanisms have lower computational and energy overhead than traditional security mechanisms, making them more suitable for low-power optical networks.

[0004] In existing technologies, fingerprint recognition technology is generally used in the physical layer security mechanism of optical networks. However, fingerprint recognition technology requires recognition through neural networks, which has problems such as high complexity due to the lack of obvious fingerprint recognition features and poor long-term stability, making it difficult to apply in real-world scenarios. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides an electro-optic modulation digital watermarking transmission method and system based on chaotic sequence pilots. Its purpose is to solve the problems of unclear identification features and poor long-term stability of traditional fingerprint recognition methods in the physical layer security of optical networks.

[0006] To achieve the above objectives, according to one aspect of the present invention, an electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots is provided, comprising:

[0007] The transmitting end will send chaotic signals As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier.

[0008] The sending end transmits the digital watermark signal to the receiving end;

[0009] The receiving end will receive the signal and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal.

[0010] Furthermore, it also includes the following steps:

[0011] Control the chaotic signal The sign of the watermark is determined to determine whether the watermark sequence is positive or negative.

[0012] Furthermore, by pre-generating a random sequence, the chaotic signal is controlled according to the positive or negative sign of the random sequence. The positive and negative.

[0013] Furthermore, the received signal for:

[0014] ;

[0015] in, Indicates optical carrier wave, , and These represent the intensity, frequency, and phase of the optical carrier, respectively. This is the bias voltage. It is a half-wave voltage. To send a signal.

[0016] Furthermore, it also includes the step of: generating the chaotic signal. .

[0017] According to a second aspect of the present invention, an electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots is provided for a transmitting end, comprising:

[0018] chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier.

[0019] The digital watermark signal is sent to the receiving end, so that the receiving end receives the signal. and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal.

[0020] According to a third aspect of the present invention, an electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots is provided for a receiving end, comprising:

[0021] The received signal and chaotic signals Correlation detection is performed to obtain the watermark sequence in the digital watermark signal;

[0022] The received signal The digital watermark signal originates from the transmitting end and is obtained through the following method:

[0023] Make the chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, the chaotic signal is embedded into the transmitted signal to obtain the digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

[0024] According to a fourth aspect of the present invention, an electro-optic modulation digital watermarking transmission system based on chaotic sequence pilots is provided, comprising a transmitter and a receiver:

[0025] The transmitting end is used to transmit chaotic signals. As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier.

[0026] The transmitting end is also used to send the digital watermark signal to the receiving end;

[0027] The receiving end is used to receive signals. and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal.

[0028] Furthermore, it also includes a control module;

[0029] The control module is used to control the chaotic signal. The sign of the watermark is determined to determine whether the watermark sequence is positive or negative.

[0030] According to a fifth aspect of the present invention, an identity authentication method is provided, comprising: obtaining a watermark sequence using an electro-optic modulation digital watermark transmission method based on chaotic sequence pilots;

[0031] The watermark sequence is used as a key to authenticate the signal transmitting device.

[0032] Wherein, the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilot is any one of the methods described in the first aspect, or the method described in the second aspect, or the method described in the third aspect.

[0033] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0034] (1) The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilot of the present invention utilizes the randomness of chaotic signals to embed chaotic signals into the transmitted signals to form digital watermark signals. The digital watermark signals contain watermark sequence information in the chaotic signals. After transmission through the channel, the receiving end performs correlation detection on the received signals and chaotic signals, and determines whether a watermark sequence exists based on the correlation between the two signals, so as to verify the identity of the transmitting device. Compared with the fingerprint recognition method in the prior art, which requires the identification of small differences in the hardware itself and requires the use of neural networks for identification, resulting in high complexity and poor long-term stability due to the lack of obvious fingerprint recognition features, the method of the present invention adopts the watermark information embedding method, directly using the watermark sequence information of the chaotic signals, and performs identity authentication at the receiving end through the relatively simple method of correlation detection, which greatly reduces the complexity of the scheme and the identification difficulty of the receiver. At the same time, the watermark sequence has the characteristics of stronger robustness and long-term stability.

[0035] Meanwhile, in the process of embedding chaotic signals into transmitted signals, this invention utilizes the electro-optic modulator bias point control that is necessary in optical communication systems. The chaotic signal is used as the pilot signal for the electro-optic modulator bias point control, thus achieving the embedding of chaotic signals into transmitted signals without increasing system complexity.

[0036] (2) Compared with the identity authentication method based on cryptographic mechanism, the present invention provides a passwordless identity authentication method in the physical layer of optical communication, which provides a new idea for the security of optical communication.

[0037] In summary, the method of this invention is the first to realize watermarking and identity authentication in an optical communication system. By embedding chaotic signals into the transmission signals to embed watermark sequence information, the identity of the legitimate sender can be authenticated, which can greatly improve the security of the optical communication process. Attached Figure Description

[0038] Figure 1 This is one of the flowcharts of the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots provided by the present invention;

[0039] Figure 2 The second schematic diagram of the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilot provided by the present invention;

[0040] Figure 3 This is a system structure diagram for a specific implementation example of the invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0042] like Figure 1 and Figure 2 As shown, this invention provides an electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots, which mainly includes the following steps:

[0043] Step S1: The transmitting end generates a broadband chaotic signal. In this embodiment, a broadband chaotic signal is generated using an external cavity delay feedback semiconductor laser chaotic entropy source. The generated chaotic signal has a bandwidth of 20 GHz;

[0044] Step S2: The transmitting end generates a chaotic signal. As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the digital watermark signal includes the transmitted signal and the watermark sequence information in the chaotic signal; the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

[0045] Step S3: After the sending end transmits the digital watermark signal through the channel, the receiving end receives the received signal. The receiving end will receive the signal and chaotic signals Correlation detection is performed to obtain the watermark sequence from the watermark sequence information.

[0046] As a further application of the above method, the present invention also provides an identity authentication method, comprising:

[0047] The watermark sequence is obtained through the above-mentioned electro-optic modulation digital watermark transmission method based on chaotic sequence pilots.

[0048] The watermark sequence is used as a key to authenticate the identity of the signal transmitting device.

[0049] In step S2, preferably, the electro-optic modulator is a Mach-Zehnder electro-optic modulator (MZM).

[0050] Specifically, in optical communication systems, it is necessary to control the bias point of the electro-optic modulator to a fixed position. However, due to factors such as temperature, the bias point may drift. In the method of this invention, by using a chaotic signal as a pilot signal for controlling the bias point of the electro-optic modulator, this drift can be detected. The feedback loop can then stabilize the bias point near the required bias voltage. At the same time, the chaotic signal can be embedded into the transmitted signal to embed watermark sequence information.

[0051] In MZM, a chaotic signal is added as a pilot signal, corresponding to the watermark sequence information embedded in the chaotic signal in the transmitted signal. At the receiving end, the correlation between the received signal and the chaotic signal is detected to determine whether the watermark sequence is carried, thereby authenticating the legitimate device. It is equivalent to adding a fixed fingerprint to the legitimate device, which can be used to distinguish between legitimate and illegitimate devices.

[0052] The above steps also include controlling the chaotic signal. The positive and negative values ​​of the chaotic pilot signal in the MZM are used to determine the positive and negative values ​​of the watermark sequence obtained after the relevant detection at the receiving end. In other words, the positive and negative values ​​of the chaotic pilot signal added to the MZM correspond to the positive and negative values ​​of the watermark sequence. This method can transmit specific information. Adding a positive chaotic pilot signal means that the watermark sequence is the transmitted signal "1", and adding a negative pilot signal means that the watermark sequence is the transmitted signal "-1". By controlling the positive and negative values ​​of the chaotic signal used as the pilot signal in real time, the transmission of arbitrary watermark sequence information can be achieved.

[0053] Specifically, in this example, a random sequence (PRBS sequence) is generated in advance, and the positive or negative sign of the chaotic signal is controlled according to the positive or negative sign of the random sequence.

[0054] Meanwhile, to ensure the accuracy of the receiver detection, the watermark sequence information in the chaotic signal should not change too quickly. Preferably, the frequency should be less than one-hundredth of the transmitted signal, that is, at least 100 signal points correspond to one embedded chaotic signal.

[0055] Specifically, let the optical carrier be denoted as Its specific form is:

[0056] ;

[0057] in, , and These represent the intensity, frequency, and phase of the optical carrier, respectively.

[0058] Let the transmitted signal be... Its specific form is:

[0059] ;

[0060] Among them, A, and These represent the strength, frequency, and phase of the transmitted signal, respectively.

[0061] After transmission through the MZM with chaotic signals as pilot signals and the channel, the received signal is obtained at the receiving end. for:

[0062] ;

[0063] in, This is the bias voltage. It is a half-wave voltage. To send a signal.

[0064] As can be seen, the phase of the received signal obtained at the receiving end already carries the added chaotic signal, that is, the chaotic signal has been successfully embedded into the transmitted signal, which means that the watermark sequence information in the chaotic signal has been embedded into the transmitted signal.

[0065] At the same time, it can be seen that the added chaotic signal only has a phase effect on the transmitted signal.

[0066] In this embodiment of the invention, the watermark sequence is obtained from the watermark sequence information through correlation analysis of the chaotic signal and the received signal.

[0067] In this embodiment of the invention, the Pearson correlation coefficient is used as the detection standard for correlation analysis. The Pearson correlation coefficient has the following form:

[0068]

[0069] Here, cov() represents the covariance between the two sequences. and These represent the standard deviations of the two sequences, where the two sequences refer to the chaotic pilot signals. and received signals .

[0070] The length of the test sequence used in correlation detection is related to the frequency of the chaotic signal. The slower the chaotic signal changes, the longer the sequence length, and the higher the accuracy.

[0071] The method provided by this invention will be further illustrated below with a specific example. For example... Figure 3As shown, a continuous-wave laser generates an optical carrier with a wavelength of 1550 nm. The polarization state is adjusted by a polarization controller (PC). A chaotic signal is used as a pilot signal to control the bias voltage of the lithium niobate MZM, simultaneously embedding the chaotic signal. A pseudo-random binary sequence (PRBS) with a bit rate of 10 Gbit / s is used as the transmitted signal. This signal is amplified by an RF amplifier (Amp) and then input to the RF electrode of the MZM. The modulation index of the MZM is defined as the peak-to-peak ratio of the RF signal voltage, and is set to 0.88.

[0072] Regarding the watermark signal, the chaotic signal The pilot signal, used for MZM bias point control, is embedded using an integrated bias control module (BCM) to integrate the pilot signal into the transmitted signal, forming a digital watermark signal. A small portion of the MZM's optical output is used, employing a 90 / 10 optical splitter (OS). One output beam from the MZM is detected by a 100 MHz bandwidth PD and then sampled by a 12-bit analog-to-digital converter (ADC) at a sampling rate of 1.4 MSa / s. A PRBS (Proportional-Integral-Derivative) signal is used to control the sign of the chaotic pilot signal, and the chaotic pilot signal and bias signal are input together to the DC bias electrode of the MZM via a DAC. The harmonic correlation between the input chaotic pilot signal and the output optical signal is calculated using a correlation integral component. The correlation is analyzed using a fuzzy proportional-integral-derivative (PID) controller, which automatically adjusts the bias voltage value.

[0073] The other output light from the MZM is transmitted as a multiplexed signal through 20km of standard single-mode fiber (SSMF). After being detected by the square law of the 10GHz bandwidth PD, it is captured by an oscilloscope (OSC) with a sampling rate of 25GSa / s. Once the signal is acquired, correlation analysis allows for the detection of the watermark sequence, thus enabling device authentication.

[0074] It should also be noted that the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots of the present invention is a two-end interactive system involving a transmitting end and a receiving end. For the transmitting end, the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots of the present invention includes:

[0075] chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the digital watermark signal includes the transmitted signal and the watermark sequence information in the chaotic signal; the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

[0076] The obtained digital watermark signal is sent to the channel, so that the received signal at the receiving end is received. and chaotic signals Correlation detection is performed to obtain the watermark sequence in the watermark sequence information, thereby enabling the authentication of the signal transmitting device.

[0077] For the receiving end, the electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots of the present invention includes:

[0078] The signal received by the receiving end and chaotic signals Correlation detection is performed to obtain the watermark sequence in the digital watermark signal, thereby enabling the authentication of the signal transmitting device.

[0079] Among them, the received signal The digital watermark signal from the sending end is used to make the chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the digital watermark signal includes the transmitted signal and the watermark sequence information in the chaotic signal; the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

[0080] According to another aspect of the present invention, the present invention provides an electro-optic modulation digital watermarking transmission system based on chaotic sequence pilots, comprising a transmitter and a receiver:

[0081] The transmitter is used to transmit chaotic signals. The pilot signal, used as the bias point control of the electro-optic modulator, embeds the chaotic signal into the transmitted signal to obtain the digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

[0082] The transmitter is also used to send the digital watermark signal to the receiver;

[0083] The receiver is used to transmit the received signal and chaotic signals Correlation detection is performed to obtain the watermark sequence in the digital watermark signal.

[0084] As a further design of the present invention, a control module is also included; the control module is used to control the chaotic signal. The sign of the watermark is used to determine the sign of the watermark sequence.

[0085] Preferably, a chaotic signal generation module is also included for generating chaotic signals. As a further preferred option, a chaotic signal is generated using an external cavity delay feedback semiconductor laser chaotic entropy source. .

[0086] In this invention, chaotic signals are utilized. Its randomness makes it a chaotic signal A digital watermark signal is formed by embedding the signal into the transmitted signal. This digital watermark signal contains watermark sequence information from the chaotic signal. After transmission through the channel, the received signal is processed at the receiving end. and chaotic signals Correlation detection is performed to determine whether a watermark sequence exists based on the correlation between the two signals. The positive or negative correlation between the two signals reflects the positive or negative watermark sequence. The watermark sequence is used as a key to verify the identity of the sending device.

[0087] Meanwhile, this invention achieves the conversion of chaotic signals During the embedded signal transmission process, the bias point control of the electro-optic modulator, which is essential in optical communication systems, is utilized. The chaotic signal is used as the pilot signal for bias point control of the electro-optic modulator, achieving the control of the chaotic signal without increasing system complexity. Embedded transmission signal.

[0088] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A digital watermarking transmission method based on chaotic sequence pilot electro-optic modulation, characterized in that, include: The transmitting end will send chaotic signals As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier. The sending end transmits the digital watermark signal to the receiving end; The receiving end will receive the signal and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal, which is used to verify the identity of the sending device.

2. The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots according to claim 1, characterized in that, It also includes the following steps: Control the chaotic signal The sign of the watermark is determined to determine whether the watermark sequence is positive or negative.

3. The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots according to claim 2, characterized in that, By pre-generating a random sequence, the chaotic signal is controlled according to the positive or negative sign of the random sequence. The positive and negative.

4. The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots according to claim 1, characterized in that, The received signal for: ； in, Indicates optical carrier wave, , and These represent the intensity, frequency, and phase of the optical carrier, respectively. This is the bias voltage. It is a half-wave voltage. To send a signal.

5. The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots according to claim 1, characterized in that, It also includes the step of generating the chaotic signal. .

6. A digital watermarking transmission method based on chaotic sequence pilots using electro-optic modulation, used at the transmitting end, characterized in that, include: chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier. The digital watermark signal is sent to the receiving end, so that the receiving end receives the signal. and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal, which is used to verify the identity of the sending device.

7. A digital watermarking transmission method based on chaotic sequence pilots using electro-optic modulation, for use at a receiving end, characterized in that, include: The received signal and chaotic signals Correlation detection is performed to obtain the watermark sequence in the digital watermark signal, which is used to verify the identity of the sending device; The received signal The digital watermark signal originates from the transmitting end and is obtained through the following method: Make the chaotic signal As a pilot signal used for bias point control of the electro-optic modulator, the chaotic signal is embedded into the transmitted signal to obtain the digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto the optical carrier.

8. A digital watermarking transmission system based on chaotic sequence pilots, characterized in that, Including the sender and receiver: The transmitting end is used to transmit chaotic signals. As a pilot signal used for bias point control of the electro-optic modulator, a chaotic signal is embedded into the transmitted signal to obtain a digital watermark signal; wherein, the electro-optic modulator is used to modulate the transmitted signal onto an optical carrier. The transmitting end is also used to send the digital watermark signal to the receiving end; The receiving end is used to receive signals. and the chaotic signal Correlation detection is performed to obtain the watermark sequence in the digital watermark signal, which is used to verify the identity of the sending device.

9. The electro-optic modulation digital watermarking transmission system based on chaotic sequence pilots according to claim 8, characterized in that, It also includes a control module; The control module is used to control the chaotic signal. The sign of the watermark is determined to determine whether the watermark sequence is positive or negative.

10. An identity authentication method, characterized in that, include: A digital watermarking transmission method based on chaotic sequence pilots is used to obtain the watermark sequence; The watermark sequence is used as a key to authenticate the signal transmitting device. The electro-optic modulation digital watermarking transmission method based on chaotic sequence pilots is the method described in any one of claims 1-5, or the method described in claim 6, or the method described in claim 7.

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