CN108377182A - A kind of the RC4 stream ciphers generating means and method of high safety - Google Patents

Abstract

The present invention relates to an RC4 stream cipher generation device and method with strong security, which solves the technical problem of low security. By adopting the RC4 stream cipher generation device, it includes a true random number generation device, a pseudo-random number generation device, and A stream cipher generation device connected to the true random number generation device and the pseudo-random number generation device through a dictionary CD; the dictionary CD is a technical solution composed of synchronous true random numbers, which better solves this problem. It can be used in communication systems such as point-to-multipoint.

Description

A device and method for generating RC4 stream cipher with strong security

technical field

The invention relates to the field of chaotic communication, in particular to an RC4 stream cipher generation device and method with strong security.

Background technique

The rapid development of communication technology has brought about great changes in human life, but there are also more and more threats, and information security has attracted more and more attention. Information security has become a sunshine industry in the 21st century. Security of confidential communication technology has important military and economic significance. One Time Pad (OTP) encryption technology is considered as the most secure encryption technology, it requires that the key is random, used only once, and the length of the key is equal to the length of the data stream. However, OTP is only used in highly confidential low-bandwidth channels due to the limitation of the distribution rate of the random number key.

In order to expand the scope of application of this encryption technology and lower the threshold of OTP technology, the researchers relaxed the requirements on the randomness of the key and proposed an encryption scheme of stream cipher. The stream cipher technology based on the randomness algorithm can use the high-speed pseudo-random sequence generated by the definite pseudo-random algorithm as the stream cipher to encrypt the data stream under the action of the limited-length seed key. RC4 algorithm is one of the best, widely used in Microsoft Office, Secure SocketLayer (SSL), Wired Equiva-lent Privacy (WEP) and so on. However, the pseudo-random number stream cipher based on the deterministic algorithm has serious security risks. With the deepening of research on the RC4 algorithm, more and more shortcomings have been discovered. The RC4 algorithm is also gradually losing its application market. However, the advantages of simplicity and high efficiency of the RC4 algorithm cannot be denied.

The existing RC4 algorithm improvement is based on the nature of the pseudo-random algorithm and has not changed. Therefore, there is a technical problem of low security. The invention adopts the method of combining pseudo-random numbers and true random numbers, and realizes flexible, high-speed, and high-security stream cipher generation based on the RC4 algorithm and a synchronous physical random number generator. Moreover, the bit error rate of the stream cipher generated by the modular addition of the pseudo-random number and the true random number is limited compared with the amplification of the bit error rate of the synchronous physical random number, which will not affect its applicability. In addition, the invention has very strong adaptability and survivability, and can be applied to point-to-point and point-to-multipoint communication systems.

Contents of the invention

The technical problem to be solved by the invention is the technical problem of low security existing in the prior art. A new RC4 stream cipher generating device with strong security is provided, and the RC4 stream cipher generating device with strong security has the characteristics of high security, flexibility and high speed.

In order to solve the above technical problems, the technical scheme adopted is as follows:

An RC4 stream cipher generating device with strong security, the RC4 stream cipher generating device includes a true random number generating device, a pseudo-random number generating device, and the true random number generating device and the pseudo-random number generating device through A device for generating stream ciphers connected to the dictionary CD; the dictionary CD is composed of synchronous true random numbers.

Working principle of the present invention: the present invention adopts the method of combining pseudo-random numbers and true random numbers, based on the RC4 algorithm and a synchronous physical random number generator, to realize flexible, high-speed, high-security stream cipher generation. Moreover, the bit error rate of the stream cipher generated by the modular addition of the pseudo-random number and the true random number is limited compared with the amplification of the bit error rate of the synchronous physical random number, which will not affect its applicability.

In the above solution, for optimization, further, the true random number synchronization device includes a synchronous physical random source, an O/E conversion module, an A/D conversion module, and a delayed XOR module.

Further, the synchronous physical random source includes a third semiconductor laser DSL, a first semiconductor laser SL1 and a second semiconductor laser SL2 connected to the third semiconductor laser; the third semiconductor laser DSL is provided with an external feedback cavity QT3, used To provide the same driving signal to the first semiconductor laser SL1 and the second semiconductor laser SL2; the first semiconductor laser SL1 and the second semiconductor laser SL2 are both provided with an external feedback cavity QT1, and the external feedback cavity QT1 and the external feedback cavity QT3 The length of the external cavity and the strength of the feedback are different. Different external feedback cavities can increase the difficulty of injection-locked synchronization, eventually making the first semiconductor laser SL1 synchronized with the second semiconductor laser SL2 but not synchronized with the third semiconductor laser DSL. Under this condition, the information of the chaotic laser signal output by the first semiconductor laser SL1 and the second semiconductor laser SL2 will not be leaked due to the interception of the output signal of the third semiconductor laser DSL, so it can be transmitted between the first semiconductor laser SL1 and the second semiconductor laser. Private synchronization between lasers SL2.

Further, the pseudo-random number generating device includes a key distribution module, an RC4 program unit connected to the key distribution module; the key distribution module is used to provide keys to the RC4 program unit; the RC4 program unit is used for Use the key provided by the key distribution module as a seed to execute the RC4 algorithm to obtain a random number sequence.

Further, the RC4 algorithm includes a key initialization algorithm and a pseudo-random number generation algorithm.

The present invention also provides a highly secure RC4 stream cipher generation method, the RC4 stream cipher generation method is based on the aforementioned RC4 stream cipher generation device, the method comprising:

Step 1, the pseudo-random number generating device generates a random number sequence by executing the RC4 algorithm;

Step 2, the true random number generating device generates synchronous true random numbers;

Step 3, combine the pseudo-random number generated by the RC4 algorithm with the true random number, including the pointer jt using the RC4 algorithm, the element in the dictionary CD pointed to is modulo-added with the pseudo-random number Zt, and the RC4 stream cipher is:

Codet=mod(Zt+CDt[jt],2 ⁿ ).

For optimization in the above scheme, further, the generation of synchronous true random numbers includes:

Step A: the third semiconductor laser DSL generates an initial chaotic laser signal under the action of external cavity feedback;

Step B: The initial chaotic laser signal is used as a driving signal, split into the same chaotic signal SG1 and chaotic signal SG2, the chaotic signal SG1 is injected into the first semiconductor laser SL1, and the chaotic signal SG2 is injected into the second semiconductor laser SL2;

Step C: the synchronous chaotic laser signals generated by the first semiconductor laser SL1 and the second semiconductor laser SL2 are converted through the photodetector in the photoelectric conversion module to obtain an electrical signal SE;

Step D: The electrical signal SE passes through the A/D module to obtain a binary sequence C2D after sampling, quantization, and judgment;

Step E: The random number sequence after the binary sequence C2D is sequentially subjected to delayed XOR is a synchronous true random number.

Further, the dictionary CD is regularly updated according to the true random number and its generation rate. The generated physical random numbers are used to form a dynamic dictionary CD (N×n bits), and the dictionary CD is dynamically updated with the continuously generated true random numbers. The update method can be continuous replacement or periodic replacement. Continuous replacement: Every time the physical random number generator generates nbits of random numbers, it immediately replaces an element in the dictionary CD, and the n-bit random number generated next time is used to replace the next element in the dictionary CD. Dictionary CD updated. Phase replacement: every time the random number generator generates N×n bits, all elements of the dictionary CD are replaced at once.

Pseudo-random number generation: It consists of a key distribution module and an RC4 algorithm. The key distribution module provides a key for both communication parties. The key is used as the seed of the RC4 algorithm, and then a random number sequence is generated through the RC4 algorithm. The transmitted data is used as the system key, and other existing key distribution methods are also applicable to this stream cipher generation scheme. In addition, the pointer j of RC4 is used to point to an element in the dictionary CD (code dictionary, dictionary CD).

RC4 algorithm: First, we define the meaning of the symbol used, n represents the length of a byte used in the algorithm (the algorithm can define the length of a byte according to user needs), N represents a word with a length of n The total number of values that can be displayed in a section, that is, N=2 ⁿ , S represents the internal state of the algorithm, and each S has N n-bit values. t represents a parameter, t=1, 2.... St represents the internal state at parameter t, and it and jt represent two pointers corresponding to parameter t, and they point to two values in internal state S. St[it] and St[jt] represent the values pointed to by pointers it and jt respectively in St. K represents a key, and l is the number of bytes contained in the key K. Zt represents the output value of the pseudo-random number generator corresponding to each t. The algorithm consists of two parts, Key Scheduling Algorithm (KSA) and Pseudo-Random Generation Algorithm (PRGA).

KSA includes N steps of operation, and the process initializes the internal state S. The specific process is shown in Table 1:

Table 1

For i=0,...,N-1 S[i]=i; j = 0 For i=0,...,N-1 j=(j+S[i]+K[i mod l]) mod 256; Swap(S[i],S[j])

PRGA first initializes the two pointers it and jt to 0 as two randomly changing pointers, and then exchanges the values pointed to by it and jt in state St-1, and the output value of this process is St[it]+St[jt] The value of the position, the specific process is shown in Table 2:

Table 2

i=j=0 i=i+1; j=j+S[i]+K[i] mod 256; Swap(S[i],S[j]) t=S[i]+S[j] Output Z=S[t]

True random number synchronization device: It is composed of a synchronous physical random source, an O/E conversion module, an A/D conversion module, and a delayed XOR module. The present invention uses chaotic laser as a physical random source. First, the third semiconductor laser (Driving Semiconductor Laser, DSL) generates an initial chaotic laser signal under the action of external cavity feedback. In order to prevent the third semiconductor laser DSL and the first semiconductor laser SL1, the second semiconductor laser SL2 has a relatively high synchronization coefficient, thereby making the information leakage of the chaotic laser signal generated by the first semiconductor laser SL1 and the second semiconductor laser SL2, in The same external feedback cavity is introduced into the first semiconductor laser SL1 and the second semiconductor laser SL2, but the external cavity length and feedback intensity of the feedback cavity are different from those of the third semiconductor laser DSL.

The synchronous chaotic laser signals generated by the first semiconductor laser SL1 and the second semiconductor laser SL2 complete the O/E conversion through the photodetector in the photoelectric conversion module. The generated electrical signal enters the A/D module, and a set of binary sequences are obtained after sampling, quantization, and judgment. The sequence is a sequence of random numbers after a time-delayed XOR.

Dictionary CD: The dictionary CD is composed of synchronous true random numbers. The dictionary CD has the same length as S, and the dictionary CD is regularly updated according to the true random number and its generation rate, that is, every time a physical random number generates an N×n-bit binary number, the original state of the dictionary CD is completely replaced. Since the elements in the dictionary CD are all derived from real random numbers, there is no fixed change relationship before and after the update. In addition, different from the state S, the dictionary CD may have the same elements. The existence of the dictionary CD is to enable true random numbers to match high-rate pseudo-random numbers when the growth rate is relatively low, thereby generating high-speed stream ciphers.

Stream cipher generation module: The stream cipher code generation module mainly combines the pseudo-random numbers generated by the RC4 algorithm with true random numbers. In order to further improve the randomness and security of the stream cipher, we have adopted the pointer jt of the RC4 algorithm, and the element in the dictionary CD pointed to is added with the pseudo-random number Zt, and the stream cipher is: Codet=mod(Zt+CDt[jt] ,2 ⁿ ).

Beneficial effects of the present invention: (1) stream ciphers are jointly produced by pseudo-random numbers and true random numbers, even if the stream ciphers produced by the same key at different times are completely different, greatly improving the performance of stream ciphers Security; (2) the present invention does not involve complex algorithm changes, and the generation rate of stream cipher is still determined by the generation rate of RC4 algorithm, and the impact of the improved stream cipher distribution scheme on RC4 algorithm is very small; (3) the present invention Complicated operations that do not involve true random numbers (such as iterative operations), the bit errors of true random numbers will not be greatly amplified in stream ciphers. (4) The present invention uses the sent data as the key of the stream cipher distribution scheme, which saves the cost. (5) Stream ciphers combine true random numbers, which can effectively resist existing attack methods, such as error introduction attacks and state guessing attacks.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic structural diagram of a specific embodiment of the present invention.

Figure 2, schematic diagram of RC4 principle.

Fig. 3. Schematic diagram of synchronous chaotic laser signal.

Fig. 4 is a schematic diagram of the correlation function between the third semiconductor laser DSL and the first semiconductor laser SL1.

Fig. 5 is a schematic diagram of the correlation function between the first semiconductor laser SL1 and the second semiconductor laser SL2.

Fig. 6 is a schematic diagram of the correlation function between the RC4 pseudo-random sequence and the stream cipher.

Fig. 7 is a schematic diagram of the correlation function between the output sequence CDt[jt] of the dictionary CD and the stream cipher.

Fig. 8 is a schematic diagram of the impact of a true random number error on the bit error rate of a stream cipher.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

The present embodiment provides a highly secure RC4 stream cipher generating device, as shown in Figure 1, the RC4 stream cipher generating device includes a true random number generating device, a pseudo-random number generating device, and the true random number generating device, The device for generating pseudo-random numbers is connected to a device for generating stream ciphers through a dictionary CD; the dictionary CD is composed of synchronous true random numbers.

Wherein, the true random number synchronizing device includes a synchronous physical random source, an O/E conversion module, an A/D conversion module and a delayed XOR module.

In detail, as shown in Figure 1, the synchronous physical random source includes a third semiconductor laser DSL, a first semiconductor laser SL1 and a second semiconductor laser SL2 connected with the third semiconductor laser; the third semiconductor laser DSL is provided with an external feedback The cavity QT3 is used to provide the same driving signal to the first semiconductor laser SL1 and the second semiconductor laser SL2; the first semiconductor laser SL1 and the second semiconductor laser SL2 are all provided with the same external feedback cavity QT1 and QT2, and the external feedback The cavity QT1 (QT2) and the external feedback cavity QT3 have different external cavity lengths and feedback strengths.

In detail, as shown in Figure 1, the pseudo-random number generating device includes a key distribution module, an RC4 program unit connected to the key distribution module; the key distribution module is used to provide keys to the RC4 program unit; the RC4 The program unit is used to use the key provided by the key distribution module as a seed to execute the RC4 algorithm to obtain a random number sequence.

Wherein, the RC4 algorithm includes a key initialization algorithm KSA and a pseudo-random number generation algorithm PRGA.

The present embodiment also provides a highly secure RC4 stream cipher generation method, the RC4 stream cipher generation method is based on the aforementioned RC4 stream cipher generation device, the method comprising:

Step 1, the pseudo-random number generating device generates a random number sequence by executing the RC4 algorithm;

Step 2, the true random number generating device generates synchronous true random numbers;

Step 3, combine the pseudo-random number generated by the RC4 algorithm with the true random number, including the pointer jt using the RC4 algorithm, and add the elements in the dictionary CD pointed to to the pseudo-random number Zt. The RC4 stream cipher is:

Codet=mod(Zt+CDt[jt],256).

The detailed working mode of the RC4 algorithm is shown in Fig. 2, where N=256, and the initial value 0, 1, 2, . . . 255 is assigned to the state S first. Then according to the length of the key, the value of the key is cyclically assigned to T. After completing the assignment, the algorithm immediately rearranges and combines the state S according to the value in T. This process is known as KSA. After the rearrangement and combination of the state S is completed, the algorithm immediately performs PRGA, and at the same time continuously executes the random number generation process in a loop to generate a pseudo-random sequence.

Wherein, the process of generating a synchronous true random number includes:

Step A: the third semiconductor laser DSL generates an initial chaotic laser signal under the action of external cavity feedback;

Step B: The initial chaotic laser signal is used as a driving signal, split into the same chaotic signal SG1 and chaotic signal SG2, the chaotic signal SG1 is injected into the first semiconductor laser SL1, and the chaotic signal SG2 is injected into the second semiconductor laser SL2;

Step C: the synchronous chaotic laser signals generated by the first semiconductor laser SL1 and the second semiconductor laser SL2 are converted through the photodetector in the photoelectric conversion module to obtain an electrical signal SE;

Step D: The electrical signal SE passes through the A/D module to obtain a binary sequence C2D after sampling, quantization, and judgment;

Step E: The random number sequence after the binary sequence C2D is sequentially subjected to delayed XOR is a synchronous true random number.

Preferably, the dictionary CD is regularly updated according to the true random number and its generation rate.

The invention is further described by taking n=8bit as an example. The third semiconductor laser DSL works around 1550 nm, and the frequency deviation between the first semiconductor laser SL1 and the second semiconductor laser SL2 is 5.8 GHz. The specific system parameters are that the operating currents of the third semiconductor lasers DSL and SLs are both 26.46mA. The feedback time and intensity of the third semiconductor laser DSL are 3ns and 15ns ^-1 respectively, and the intensity and delay of the third semiconductor laser DSL injected into SLs are 45ns ^-1 and 0ns respectively. Under this condition, the feedback time and intensity of the first semiconductor laser SL1 and the second semiconductor laser SL2 are 2 ns and 10 ns ⁻¹ respectively. In order to verify the feasibility, the synchronization performance between the first semiconductor laser SL1 and the second semiconductor laser SL2 is studied.

Figure 3 shows the short-term output intensities of the first semiconductor laser SL1 and the second semiconductor laser SL2. Under the above working conditions, the chaotic laser signals generated by the first semiconductor laser SL1 and the second semiconductor laser SL2 are well synchronized.

In order to quantitatively study its synchronization quality, the cross-correlation function of the two is evaluated, and the result is shown in Figure 4. The correlation coefficient of the two is close to 1 when the lag time is 0ns, so we can further determine the first semiconductor laser SL1 has a very high synchronization quality with the second semiconductor laser SL2.

In addition, the correlation function between the third semiconductor laser DSL and the first semiconductor laser SL1 is estimated, as shown in Figure 5, it has the highest correlation coefficient when the lag time is 0 ns, and the correlation coefficient is close to 0.6 .

If the injection intensity of the third semiconductor laser DSL to the first semiconductor laser SL1/2 is further reduced, the correlation coefficient can be further reduced.

Under ideal conditions (neglecting the influence of the above factors), when the correlation coefficient between the third semiconductor laser DSL and the first semiconductor laser SL1 is 0.6, it is obtained from the injection signal, that is, the output signal of the third semiconductor laser DSL The bit error rate of physical random numbers is about 0.24. Considering the synchronization error, sampling clock jitter, and clock mismatch in the actual interception process, the bit error rate of synchronous physical random numbers intercepted from the chaotic laser signal output by the third semiconductor laser DSL is much higher than 0.24. Therefore, the third cracking party cannot intercept useful information from the injected signal.

Fig. 6 is a correlation function between the pseudo-random sequence Z and the final stream cipher sequence. What adopted in the present embodiment is the method for updating the dictionary CD in stages, as shown in the figure, the correlation coefficient between the final stream cipher sequence and the pseudo-random sequence is very small (less than 0.004), that is, the final stream cipher sequence and RC4 produce The pseudo-random sequence is irrelevant, which means that the scheme of the third cracking party trying to introduce the attack through the error or the Kundsen state guessing attack basically loses its effectiveness.

For the error attack scheme: Assume that the attacker controls the cryptographic device, can correctly use the cryptographic device for encryption, and can also introduce errors into the cryptographic device, thereby affecting the encryption process and causing the cryptographic device to output wrong encryption results. According to the existing technology, to break the RC4 algorithm and restore the entire initial state result of RC4, 2 ¹⁶ key words and 2 ¹⁶ error introduction attacks are needed.

However, the update frequency of the dictionary CD in the embodiment is 1.22 MHz (determined by the rate of generating random numbers). Once the error introduction attack fails to decipher the entire initial state of RC4 within the dictionary CD update cycle, the third cracking party must decipher from the beginning. On the other hand, even if the third cracking party knows the initial key and re-runs the encryption device, the stream cipher used before cannot be produced due to the continuous update of the dictionary CD.

Fig. 7 is the correlation function of stream cipher and dictionary CDt[jt] sequence. As shown in the figure, the correlation coefficient between the two is still less than 0.004, that is, the final stream cipher sequence is not correlated with the dictionary CDt[jt] sequence. That is, even if the third cracking party controls the synchronous random number generator and uses it to generate correct random numbers, it cannot generate the correct stream cipher without determining the pseudo-random sequence and pointer jt sequence generated by RC4 .

FIG. 8 shows the relationship between the bit error rate of the stream cipher and the bit error rate of the synchronous physical random number. According to the existing synchronous random number generation system based on a synchronous physical entropy source, due to sampling errors such as clock jitter and synchronization errors of the physical entropy source, the synchronous physical random number has a high bit error rate under the condition of no data transmission. The bit error of the random number will inevitably lead to the bit error of the stream cipher, so the relationship between the bit error rate of the stream cipher and the bit error rate of the synchronous physical random number is very important. As shown in Figure 8, the bit error rate of the stream cipher has an approximately linear relationship with the bit error rate of the synchronous physical random number, and the bit error rate y of the stream cipher is slightly larger than the bit error rate x of the physical random number. The data obtained by linear fitting can be obtained as y=1.73674x+1.28965×10 ^-6 .

From this, we can deduce that when the correlation coefficient of the correlation function between the third semiconductor laser DSL and the first semiconductor laser SL1 is 0.6, under ideal conditions, the third cracking party extracts a physical random number from the injected optical signal and The bit error rate of the stream cipher produced by the same method is ~0.42.

To verify the randomness of stream ciphers, we tested them against NIST 800-22. Table 3 shows the NIST 800-22 test results for 2.5Gb/s physical random numbers and 100Gb/s stream ciphers. As shown in the table, both sequences were able to pass 15 NIST tests.

table 3

In summary, this embodiment has the following features: (1) the security of the key mainly depends on the security of the physical random number and the security of the seed key; The physical random source, combined with subsequent module generation, is a physical true random number; (3) By changing the external cavity structure of the laser at the receiving end, the physical random source and the driving light source are not synchronized, preventing the leakage of the physical random entropy source due to the injection signal (4) Use the sent data to learn that the mature low-speed key distribution technology is the seed key of the RC4 algorithm, and the algorithm complexity is low; (5) Use the pseudo-random sequence generated by the RC4 algorithm and the value of the pointer j The specified dictionary CD elements are modulo-added as a stream cipher. This process does not involve the iterative operation of physical random numbers, so it will not cause a sharp increase in the bit error rate; (6) combine the physical random numbers with the pseudo code generated by RC4 The combination of random numbers can eliminate the distribution deviation of RC4 pseudo-random numbers caused by different seed keys, and effectively resist state guessing attacks (a commonly used RC4 attack method); (7) this embodiment has a high degree of applicability , suitable for point-to-point and point-to-multipoint communication systems, so it can play a role in almost all communication systems; (8) The rate of the stream cipher is still determined by the generation rate of RC4, so it has very high flexibility and high speed.

Although the illustrative specific embodiments of the present invention have been described above, so that those skilled in the art can understand the present invention, the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as each As long as the changes are within the spirit and scope of the present invention defined and determined by the appended claims, all inventions and creations using the concept of the present invention are included in the protection list.

Claims (8)

1. a strong RC4 stream cipher generating device for security, characterized in that: said RC4 stream cipher generating device comprises a true random number generating device, a pseudo-random number generating device, and with said true random number generating device, said The pseudo-random number generation device is connected to the stream cipher generation device through the dictionary CD; the dictionary CD is composed of synchronous true random numbers. 2. the strong RC4 stream cipher generation device of security according to claim 1, is characterized in that: described true random number synchronization device comprises synchronous physical random source, O/E conversion module, A/D conversion module and time delay XOR module. 3. the strong RC4 stream cipher generation device of security according to claim 1, is characterized in that: described synchronous physical random source comprises the 3rd semiconductor laser DSL, the first semiconductor laser SL1 that is connected with the 3rd semiconductor laser and the 3rd semiconductor laser Two semiconductor lasers SL2; the third semiconductor laser DSL is provided with an external feedback cavity QT3 for providing the same drive signal to the first semiconductor laser SL1 and the second semiconductor laser SL2; the first semiconductor laser SL1 and the second semiconductor laser SL1 The laser SL2 is all provided with an external feedback cavity QT1, and the external cavity length and feedback strength of the external feedback cavity QT1 and the external feedback cavity QT3 are different. 4. the strong RC4 stream cipher generation device of security according to claim 1, is characterized in that: described pseudo-random number generation device comprises key distribution module, the RC4 program unit that is connected with key distribution module; The key distribution module is used to provide keys to the RC4 program unit; The RC4 program unit is used to use the key provided by the key distribution module as a seed to execute the RC4 algorithm to obtain a random number sequence. 5. The RC4 stream cipher generation device with strong security according to claim 1, characterized in that: the RC4 algorithm comprises a key initialization algorithm and a pseudo-random number generation algorithm. 6. A strong RC4 stream cipher generation method for security, characterized in that: the RC4 stream cipher generation method is based on the RC4 stream cipher generation device described in claim 1-5, and the method comprises: Step 1, the pseudo-random number generating device generates a random number sequence by executing the RC4 algorithm; Step 2, the true random number generating device generates synchronous true random numbers; Step 3, combine the pseudo-random number generated by the RC4 algorithm with the true random number, including the pointer jt using the RC4 algorithm, the element in the dictionary CD pointed to is modulo-added with the pseudo-random number Zt, and the RC4 stream cipher is: Codet=mod(Zt+CDt[jt],2 ⁿ ). 7. the strong RC4 stream cipher generation method of security according to claim 6 is characterized in that: the true random number of described generation synchronization comprises: Step A: the third semiconductor laser DSL generates an initial chaotic laser signal under the action of external cavity feedback; Step B: The initial chaotic laser signal is used as a driving signal, split into the same chaotic signal SG1 and chaotic signal SG2, the chaotic signal SG1 is injected into the first semiconductor laser SL1, and the chaotic signal SG2 is injected into the second semiconductor laser SL2; Step C: the synchronous chaotic laser signals generated by the first semiconductor laser SL1 and the second semiconductor laser SL2 are converted through the photodetector in the photoelectric conversion module to obtain an electrical signal SE; Step D: The electrical signal SE passes through the A/D module to obtain a binary sequence C2D after sampling, quantization, and judgment; Step E: The random number sequence after the binary sequence C2D is sequentially subjected to delayed XOR is a synchronous true random number. 8. The RC4 stream cipher generating method with strong security according to claim 6, characterized in that: said dictionary CD is regularly updated according to true random numbers and their generation rate.