CN107528687A - Dynamic key based on physical layer channel cross correlation quantifies machinery of consultation - Google Patents

Abstract

The invention discloses a dynamic key quantization negotiation method based on wireless physical layer channel characteristics, which solves the problems of low key generation rate and low entropy value in the existing quantization negotiation method. The quantization negotiation process includes: both parties of data communication collect communication data information in advance, initialize the key quantization negotiation parameters, the communication party performs dynamic packet slope quantization on each piece of data after segmentation to obtain the initial key, and the communication parties record the array and Discard the array to conduct key agreement on the initial key, and finally both parties get the final key. The invention improves the key stream generation rate, and can generate 128-256bit key stream within about 200 seconds. It ensures that the key stream entropy value is high, which is better than the upper and lower interval quantization algorithm and the fixed group slope quantization algorithm. The invention is applied to the key generation negotiation in wireless network encryption communication to realize safe communication.

Description

Dynamic Key Quantization Negotiation Method Based on Physical Layer Channel Correlation

technical field

The invention belongs to the technical field of wireless network security, and mainly relates to key quantization negotiation in wireless network communication, in particular to a dynamic key quantization negotiation method based on physical layer channel mutual correlation, which is used for wireless network security communication.

Background technique

Establishing a secure communication channel is the foundation and the most important security requirement of wireless networks, because wireless networks involve all aspects of our daily safety and security applications. Traditional network security mechanisms rely on keys to support confidentiality and authentication services.

However, in a dynamic mobile wireless environment, it is difficult to guarantee the availability of a certificate management authority or a key management center even if there is a peer-to-peer association between instant mobile entities. With the help of the wireless channel established between the wireless terminal (STA) and the access point (AP) in the wireless network environment, there is a certain cross-correlation, and the wireless channel characteristics shared by both parties with correlation are used for key quantization negotiation, and the key is extracted from it. Generate a key stream that is sufficient to guarantee a certain security strength.

A recent trend in this regard is to use the Received Signal Strength (RSS) of the wireless channel to extract keys. Received Signal Strength (RSS) is a popular statistic of radio channels and can be used as a source of shared secret information between transmitter and receiver.

The traditional method of using RSS to carry out key quantization negotiation, such as the quantization method based on the upper and lower interval thresholds, has many shortcomings, especially in the static situation: (1) its fatal weakness is the low bit generation rate; (2) The generated key has low entropy (sequence with consecutive multiple 0s or consecutive multiple 1s), which reduces the confidentiality; (3) cannot effectively resist the predicted channel attack, because if the channel is periodically blocked, the RSS Reads will increase or decrease.

Contents of the invention

The object of the present invention is to propose a dynamic key quantization negotiation method based on physical layer channel mutual correlation with fast key generation rate and high key entropy value in view of the deficiencies in the prior art.

The present invention is a kind of dynamic key quantitative negotiation method based on wireless physical layer channel characteristic, it is characterized in that, comprises following steps:

Step 1: The two parties in the data communication pre-collect the communication data information: first, the two parties establish a wireless channel with mutual correlation, interact within a fixed time, and each obtain the data packets collected by sending a fixed time at a fixed sending rate. Extracting the channel eigenvalues in each data packet, respectively forming a string of input data for key quantization;

Step 2: Both parties in the data communication initialize key quantization parameters: both parties segment the input data for key quantization respectively, and the reference point of each initial grouping is initialized as the first data point of the segment, and the grouping of each segment The serial numbers start from 1, and set the slope threshold;

Step 3: One party of the data communication performs dynamic grouping slope quantification on each piece of segmented data in turn:

3.1 The data communication party selects the first segment of data, starts from the reference point of this segment, and compares the subsequent data points with the reference point in turn. If the absolute value of the difference between the current data point and the reference point is greater than the slope threshold, then Carry out key quantization, generate a bit, and record the current data point as the end point of the current group, save the subscript of the data point in the subscript record of the group, increase the group number by 1, and the reference point of the next group is that of the previous group End point; otherwise discard the data point and compare the next data point until the end of the group to generate a bit; this process completes the bit quantization of a group;

3.2 The data communication party will perform dynamic packet quantization on the segment of data in turn according to step 3.1. One packet quantization generates one and only one bit, and one bit generated by each packet quantization is sequentially stored in the quantized bit string. If the quantized bit string is empty, the currently generated bit is the quantized bit string; otherwise, the generated bit is spliced to the end of the quantized bit string; this process completes the group bit quantization of a piece of data;

3.3 The data communication party performs bit quantization on each piece of data according to step 3.2, splices each piece of quantized bit string obtained after quantization in turn to generate the original quantization key, and obtains the result of key quantization, that is, the original quantization key and the grouping marked record;

Step 4: The two parties of the data communication conduct the key negotiation process according to the subscript record of the group and the discarded array. The specific negotiation process includes:

4.1 One party of the data communication sends the group subscript record in the key quantization result to the other party;

4.2 After the other party of the data communication receives the group subscript record of the other party, it performs group key quantization on its own input data for key quantization according to the group subscript record. If the current group has no generated bits, the group is downloaded. If the quantized bit string is empty, the currently generated bit is the quantized bit string; otherwise, the generated bit is spliced into the quantized bit string. Quantize the tail of the bit string. After quantization, the other party obtains the key quantization result, that is, the quantized bit string and the discarded array. The other party sends the discarded array to the other party. The quantized bit string is used as the final quantized key of the other party;

4.3 After receiving the discarded array from the other party, the other party of the data communication discards the corresponding grouped quantized bits in its original quantized key in turn according to the discarded array to obtain the final quantized key and complete the key negotiation process between the two parties;

Step 5: the key quantization negotiation process of both parties of the data communication ends, and both parties respectively obtain a string of 01 bit key streams with sufficient security length 128-256bit, and realize wireless encrypted communication under the environment of this quantization negotiation key.

In the present invention, instead of using a fixed threshold to generate a key, the key is quantized by using the difference between the RSS values of two channel characteristic data points, that is, the slope value. Using the present invention, more robust keys can be generated in less time.

Compared with prior art, technical advantage of the present invention:

1. The quantization process of the present invention adopts the dynamic grouping method, combined with the slope threshold quantization method, when the absolute value of the difference between the data point and the reference point meets the threshold value requirement, it can be divided into an effective grouping, and the effective grouping number of the channel characteristic data is large Amplitude improves, and the average grouping length of dynamic grouping method is less than the fixed grouping length set in the fixed grouping method, so use the method of the present invention to generate the key generation rate higher, experiment proves, use the present invention, generate 128-200 seconds The bit key stream of about 256bit, the dynamic packet quantization negotiation method effectively improves the key generation rate;

2. The present invention adopts the feature of the difference between adjacent channel data points to protect and describe the characteristics of the channel data to the greatest extent, so that the entropy value of the quantization negotiation key is high, and it is also because the key generated by the present invention has Higher entropy value ensures the security of data confidentiality in wireless communication;

3. When the method of the present invention performs quantization key generation, it will not be affected by the displacement of the channel characteristic value received by both parties of data communication, because the used data characteristic is the difference between adjacent data points, and the data points will contain Therefore, the displacement of the channel characteristic data has no effect on the quantization negotiation key generation rate and entropy value, which is better than the previous interval threshold quantization algorithm.

4. In the key negotiation process of the present invention, the interactive data is only the group subscript record array and the discarded array, and what the array stores is the subscript of the data point, rather than the RSS value of the data point, which better ensures the RSS data Security, that is, do not send any content related to the RSS value to the outside world. Even if the eavesdropper captures these two arrays, he cannot recover the quantization key from them. This resists predictive channel attacks to a certain extent and enhances the security during the key agreement process.

Description of drawings

Fig. 1 is a schematic diagram of key quantization flow chart of the present invention;

Fig. 2 is a quantized line diagram of both communication parties of the present invention;

FIG. 3 is a sequence diagram of key agreement between communicating parties in the present invention.

detailed description

Below in conjunction with accompanying drawing the present invention is described in detail,

Example 1

The Achilles heel of the quantization method based on the upper and lower interval thresholds in the existing wireless communication key quantization negotiation method is that the key bit generation rate is low, and the generated key entropy value is low, which cannot effectively resist the attack of the attacker on the key. The brute force cracking reduces the confidentiality. In response to this situation, the present invention has launched research and innovation, and proposes a dynamic key quantization negotiation method based on wireless physical layer channel characteristics. In the wireless network environment architecture based on the 802.11 protocol, it is generally composed of wireless terminals and access points. The wireless terminal sends a probe request frame to the access point in active scanning mode. After receiving the probe request frame, the access point sends a probe response frame to respond to the wireless terminal. This process facilitates the establishment of a wireless channel in the wireless space for both communication parties. On the theoretical physical level of wireless communication, the channel characteristics of this channel are unique, and the two channels are different, but the channel characteristics received by the communication parties connected to the channel are theoretically consistent, and in reality, it will be affected by environmental noise, etc. factors, but still have a strong correlation. In this example, by using the mutual correlation of the physical layer channel, a set of channel characteristic sequences shared only by both communication parties is obtained, and this channel characteristic sequence is used as secret information for key quantization negotiation. See Figure 1 for the specific key quantization negotiation process, including the following steps:

Step 1: The two parties in the data communication pre-collect the communication data information: first, the two parties establish a wireless channel with mutual correlation, interact within a fixed time, and each obtain the data packets collected by sending a fixed time at a fixed sending rate. The channel eigenvalues in each data packet are extracted to form a string of input data for key quantization.

In this example, the ping program is used to send data packets to the STA and the AP to interact, the sending rate is set to 10 packets/second, the interaction time is set to 200 seconds, each obtains about 1800 data packets, and extracts each data packet The RSS values in each constitute a string of input data for key quantization.

Step 2: Both parties in the data communication initialize key quantization parameters: both parties segment the input data used for key quantization obtained in step 1, the segment length is set to 100-300, and the reference point of each initial grouping is initialized It is the first data point of the segment, the group number of each segment starts from 1, and the slope threshold is set. In this example, the slope threshold is set to 4, and the segment length is set to 100.

Step 3: One party of the data communication performs dynamic grouping slope quantification on each piece of segmented data in turn:

3.1 Bit quantization of a packet data: the party of data communication selects the first segment of data, starts from the reference point of this segment, and compares the subsequent data points with the reference point in turn, if the absolute value of the difference between the current data point and the reference point When the value is greater than the slope threshold, key quantization is performed, a bit is generated, and the current data point is recorded as the end point of the current group, the subscript of the current data point is saved in the group subscript record, the group number increases by 1, and the next group The reference point is the end point of the previous group; otherwise, the data point is discarded, and the next data point is compared until the end of the group to generate a bit; this process completes the bit quantization of a group. The dynamic grouping method adopted in the present invention can ensure a high rate of key generation, and will not be affected by the displacement of channel characteristic values received by both parties of data communication when generating quantized bits.

3.2 Group bit quantization of a piece of data: the data communication party will perform dynamic group quantization on the piece of data in turn according to step 3.1. One group quantization generates one and only one bit, and one bit generated by each group quantization is stored in the existing In the quantized bit string, if the quantized bit string is empty, the currently generated bit is the quantized bit string; otherwise, the generated bit is spliced to the end of the quantized bit string, and this process completes the grouping of bits for a piece of data Quantify.

3.3 Obtain the key quantization result: the data communication party performs bit quantization on each piece of data according to step 3.2, and splices each piece of quantized bit string obtained after quantization in turn to obtain the key quantization result, that is, the original quantization key and grouping subscript record.

Referring to Figure 2, the above grouping process is described by taking the first grouping as an example. Starting from the reference point (the point whose abscissa is 1), the subsequent data points are compared with the reference point in turn, and the subscript is 2 data points and the other The RSS value is 26dB, the difference between this point value and the reference point value of 27dB, the difference is -1dB, the absolute value is 1dB, less than the slope threshold 4, no key generation is performed, and the comparison to the next point is continued, when the comparison reaches the fourth data At this point, the RSS value at this point is 32dB, the difference is 5dB, and the absolute value is 5dB, which is greater than the slope threshold 4, and the key is generated, and the difference is 5dB>0, the quantization bit of this group is 1, and it is stored in the In the quantized bit string, the party of the data communication regards the data point subscript 4 as the group subscript and saves it in the group subscript record, and at the same time uses the 4th point as the reference point of the next group. This completes the bit quantization of the first packet.

Step 4: The two parties in the data communication conduct the key negotiation process according to the subscript record of the group and the discarding array. See Figure 3. In this example, one party of the data communication is Alice, and the other party is Bob. The specific negotiation process is as follows:

4.1 Alice, one party of the data communication, sends the group subscript record in the key quantization result to the other party, namely Bob.

4.2 Bob, the other party in the data communication, receives the group subscript record from Alice, and performs group key quantization on his own input data for key quantization according to the group subscript record. If there is no generated bit in the current group, the The subscript of the group is recorded in the discarded array; otherwise, the generated bit is stored in the quantized bit string. If the quantized bit string is empty, the currently generated bit is the quantized bit string; otherwise, the generated bit is concatenated At the end of the quantized bit string, after quantization, the other party Bob obtains the key quantization result, that is, the quantized bit string and the discarded array, and the other party Bob sends the discarded array to Alice, and the quantized bit string is used as the final quantization key.

4.3 Alice, the other party of data communication, receives the discarded array from the other party Bob, discards the corresponding grouped quantized bits in her original quantized key in turn according to the discarded array, obtains the final quantized key, and completes the key negotiation process between the two parties.

Step 5: the key quantization negotiation process of both parties of the data communication ends, and both parties respectively obtain a string of 01 bit key streams with sufficient security length 128-256bit, and realize encrypted wireless communication under the environment of this quantization negotiation key.

In the existing fixed group key quantization negotiation method, the key generation rate is low. The reason is that the channel characteristic data received by the two communication parties fluctuate less within a fixed period of time, resulting in too few valid data points. The number is relatively small; the generated key entropy value is low, and the key has a sequence of consecutive multiple 0s or consecutive multiple 1s, which reduces the confidentiality; it is very vulnerable to predicted channel attacks because if the channel is blocked periodically, the reading of the channel eigenvalue will be incremented or decremented.

The present invention is a new method proposed on the basis of the method for generating fixed group keys, and seeks a new way of extracting keys from dynamic groups instead of obtaining keys from fixed groups.

The present invention proposes a dynamic packet slope quantization method in the key quantization process. Since a group of channel eigenvalue sequences cannot be monotonous, the situation of generating continuous 0 or continuous 1 keys is avoided, and some improvements are made to the original method. Technical improvement, changing from fixed grouping to dynamic grouping, introducing fluctuation parameters for threshold quantization, increasing the number of valid data points, and changing the quantization method from the quantization of the mean value within the group to the quantization of the difference between the first and last points in the group, reducing the amount of calculation, thus The key quantization generation rate is further improved.

Example 2

The dynamic key quantization negotiation method based on wireless physical layer channel characteristics is the same as embodiment 1. The channel characteristic value used in step 1 of the present invention is received signal strength (RSS), and the fixed transmission rate is generally set to 10 packets/second. The fixed time is usually 200 seconds, so that the communication parties can collect more channel characteristic data information within a limited time, so as to better reflect the characteristics of the channel and ensure the unpredictability of the key.

In this example, the sending rate is 20 packets/second, and the duration is 200 seconds. About 3,500 packets can be collected except packet loss. If the sending rate is further increased, when the sending rate exceeds 50 packets/second, the packet loss rate will decrease. A substantial increase, reaching about 30%.

Example 3

The dynamic key quantization negotiation method based on wireless physical layer channel characteristics is the same as embodiment 1-2, and the slope threshold value in step 2 is determined by parameter elps and fluctuation parameter d, and the definition formula of slope threshold value (cmp) is cmp=elps/d, Among them, the parameter elps is defined as the critical value, which is the average value of the difference between all adjacent data points in a piece of data. Generally, the value is 2-4. The fluctuation parameter d is used to reduce the impact of small fluctuations on key generation. Generally, The value is 0.5-1.

In this example, the parameter elps is set to 2, and the fluctuation parameter is set to 1, because in the test environment of this example, both parties are in a static state, and both parties conduct experiments in the same room, so the fluctuation of the channel characteristic data is small, and the slope threshold will be reduced accordingly. small.

Example 4

The dynamic key quantization negotiation method based on wireless physical layer channel characteristics is the same as that in Embodiment 1-3, when each packet described in step 3.1 generates a bit, specifically, if the difference between the current data point and the reference point is positive, Then the group quantization bit is 1; if the difference between the current data point and the reference point is negative, the group quantization bit is 0.

In this example, the parameter elps is set to 4, the fluctuation parameter is set to 0.5, and the slope threshold is calculated as 4/0.5=8, because in the test environment of this example, the AP is in a corridor and is in a static state, and the STA is in a room next to the corridor, and In the state of motion, the collected channel characteristic data fluctuates greatly, and there will be sudden changes in the RSS value of individual data points, so the slope threshold is increased accordingly to reduce the bit error rate of key generation.

Example 5

The dynamic key quantization negotiation method based on wireless physical layer channel characteristics is the same as that in Embodiment 1-4, and the absolute value of the difference Δ in step 3.1 is defined as |Δ|=|array[i]-array[start]|, where array is Enter the data column, i is the subscript of the current data point, and start is the current grouping reference point.

In this example, the slope quantization can be summarized as intra-group first-to-tail difference quantization. Compared with the intra-group mean and reference value quantization, the calculation amount is small, which also illustrates the high key generation rate of the present invention from another perspective.

Example 6

The dynamic key quantization negotiation method based on the channel characteristics of the wireless physical layer is the same as that in Embodiments 1-5. In Step 4 of the present invention, the grouping information is recorded in the grouping subscript record array, and the grouping subscript array is marked as segment, and each element in it is saved What is the subscript of the end point of each group, segment[0] is the first element of the segment array, and the number of groups is stored in segment[0]; the discarded array is denoted as UB, and each element saves The end subscript of each discarded group, UB[0] is the first element of the UB discarded array, and the number of discarded groups is stored in UB[0].

In the negotiation process of this example, the interaction data is only the above two arrays, and the array stores the subscript of the data point, not the RSS value of the data point. This better ensures the security of the RSS data, that is, it does not send Send any content related to the RSS value, even if the eavesdropper captures these two arrays, he cannot recover the quantization key from them.

The present invention is further described with another example below:

Example 7

The dynamic key quantization negotiation method based on wireless physical layer channel characteristics is the same as that in Embodiment 1-6, referring to Fig. 1, one of the communication parties is Alice, and the other is Bob, and the specific steps are described as follows:

Step1: Within a fixed period of time, Alice and Bob, both communicating parties, send and receive data packets collected by each other through a wireless communication link at a fixed sending rate for a fixed duration. The fixed sending rate is 10 packets/second, and the fixed duration is 300 seconds. Both parties extract and save a set of channel characteristic values from more than 2,700 collected data packets respectively. The present invention uses RSS as the channel characteristic value, and records the length of this group of data as Len.

Step2: Alice and Bob initialize the grouping parameters, the reference point of the first grouping is the first data element, set the traversal starting point start and initialize it as the subscript of the second element.

step3: Calculate the slope reference value cmp=elps/d, where the parameter elps is defined as the critical value, and the parameter d is used to reduce the impact of small fluctuations on key generation, and the calculated slope threshold is intended to be used as a threshold in the quantization process To decide whether to generate a bit in the current packet quantization;

Step4: Traversing from the start position, when the start position exceeds the maximum value of the subscript of the data element, jump to step7;

Step5: When the absolute value of the difference Δ between the current point and the reference point is greater than cmp, execute step6; otherwise, update start to point to the next element of the data, and return to execute step4.

Step6: The current group ends, the number of groups increases by 1, records the current start as the end point of this group, saves the subscript of the end point of the group in the segment array, and updates the start' of the next group's traversal start'.

step6.1 If Δ>0, the quantized bit result of the packet is marked as 1;

step6.2 If Δ<0, the quantized bit result of the packet is marked as 0;

In this example, the grouping size of the dynamic grouping is determined by the characteristics of the sample data to be quantized. The advantage of this is that the quantization result is closer to the characteristics of the data itself. When the difference between the data point and the reference point meets the threshold requirement, it can be divided into a new group, which can ensure the maximum generation efficiency of quantization results, that is, the maximum key generation rate.

Step7: The two parties start the key negotiation process, see Figure 3, Alice saves the current group number in the segment[0] position, then saves the group record array segment and the quantization result quant array locally, and sends the segment array to Bob at the same time, According to the received segment array, Bob quantizes the RSS data group obtained from step 1 and records it in the quantized bit string. For the packets that cannot be quantized, record them in the discarding array UB. After quantization, the quantized bit string is For the final quantization key, Bob sends the UB array back to Alice.

Step 8: After receiving the UB array, Alice discards the corresponding group quantization bits in her initial quantization key according to UB, and Alice obtains the final quantization key.

Since the characteristics of RSS data in a specific set of scenarios are not clear before quantification, the adoption of fixed grouping makes the algorithm less adaptable, and the monotonicity of data points in each fixed-length grouping is not unique, which makes the slope algorithm unable to play Its maximum efficacy, resulting in a small amount of key generation and a low rate of key generation. If the dynamic packet slope algorithm of the present invention is adopted, this weakness will be overcome, and the data points in each variable-length packet are monotonous. The quality of the quantization results only depends on whether the absolute value of the slope within the group exceeds the quantization threshold. In this way, the key generation rate is greatly improved, and the bit error rate is relatively reduced.

The present invention is not affected by the displacement of the RSS value received by both communication parties when generating the quantization key, which is superior to the existing upper and lower interval threshold quantization algorithms.

A comprehensive and more detailed example is given below to further illustrate the present invention,

Example 8

The dynamic key quantization negotiation method based on the channel characteristics of the wireless physical layer is the same as that of Embodiment 1-7, refer to the table of experimental test results, namely Table 1,

Table 1 Two existing quantization methods and this method in different experimental scenarios quantization key length table

According to the probe data packets sent and received between Bob and Alice, a set of sufficiently long channel characteristic value sequences can be collected within a fixed time period of 200 seconds, taking the RSS value as an example.

Different from adopting the fixed threshold quantization of the upper and lower intervals to generate the key, in the dynamic grouping slope quantization method of the present invention, the relative difference between two adjacent RSS values is used to determine a key bit, and the "static/dynamic" in Table 1 10pkg/s" as an example to explain the experimental description. The access point AP is in a static state, the wireless terminal STA is in a moving state, and the sending rate is 10 packets/s. The specific steps are as follows:

1) Alice and Bob each obtain a string of RSS test sequences, the length of the test sequence is Len=1523, and divide the test sequence into m segments, m=15, each segment has t elements, t=100, t is the segment length , the remaining 23 data points are discarded;

2) Determine the fluctuation parameter d, which is used to reduce the impact of small data fluctuations on key generation, and is set to 0.8;

3) Determine the critical value parameter elps, set as 3;

4) Determine the slope threshold cmp=elps/d, and substitute the data cmp=3/0.8=3.75;

5) extract key, in key quantization process of the present invention, will carry out grouping successively by dynamic method to each piece of data, every group has two elements at least, concrete process is as follows:

The starting element of the first grouping of each piece of data is used as a reference value, and the following data points are compared with the reference value in turn. If the absolute value of the difference is greater than cmp, this data point is considered to be the end point of the current grouping and used The condition for grouping to generate a bit, the data point is recorded as the end element of this group, the quantization result is stored in the quantized bit string, and the end element of the group will be used as the starting element of the next group, and the previous operation is continued ; and if this data point cannot reach the standard of becoming the end point of the current group and making the group generate one bit, the subscript of the current data point will be expanded by one bit, and the absolute value of the difference between the current data point and the grouping reference value will be recalculated, and the decision will be made. Whether the current data point can become the end point of the packet and cause the packet to generate a bit, and so on.

The quantized bit string obtained from each segment is sequentially spliced. At this point, the quantization process of Alice's key is over, and Alice generates her own initial quantized key, and obtains the group subscript record array segment.

Next, the two parties will conduct key negotiation. The specific method is as follows: Alice sends the segment array to Bob, and Bob quantifies the key according to the segment array sent by Alice, and recalculates the bits that Alice has determined to group but cannot determine the group by himself. Try whether the smaller elps value can match, thereby improving the key generation rate, if it still cannot match, record the subscript of the group in the discarding array UB;

Then Bob sends the UB array to Alice, and Alice adjusts again, discarding some bits of her initial quantization key according to UB;

Finally, Alice and Bob get their respective final quantization keys with a length of 264 bits, and complete the whole quantization negotiation process.

The new type of dynamic key quantization negotiation method based on the mutual correlation of wireless physical layer channel characteristics designed and implemented by the present invention adopts the dynamic grouping slope to quantify the channel characteristic value and carry out information coordination, and finally obtains a series of sufficiently secure key streams with high efficiency. It can guarantee to generate 128-256bit key stream within about 200 seconds, which improves the key stream generation rate, and at the same time ensures that the random entropy of the key stream is high, which is better than the traditional quantization algorithm of upper and lower interval thresholds, and also excellent Based on the fixed group slope quantization algorithm.

In short, the invention discloses a dynamic key quantization negotiation method based on wireless physical layer channel characteristics, which solves the problems of low key generation rate and low entropy value of existing quantization negotiation algorithms. The quantization negotiation process includes: both parties of data communication collect communication data information in advance, initialize key quantization negotiation parameters, one party of data communication performs dynamic packet slope quantization on each piece of segmented data in turn to obtain the initial key, and the two parties of data communication according to The group index record array and the discarding array perform key negotiation on the initial key, and finally both parties obtain the final key. The present invention improves the generation rate of the key stream, and at the same time ensures that the entropy value of the key stream is relatively high, and both communication parties can generate a 128-256 bit key stream within about 200 seconds.

The invention is applied to wireless network encrypted communication, and is specifically used for key generation negotiation, and the obtained key can be used as an encryption key in encrypted communication to realize safe communication.

Claims (5)

1. a kind of dynamic key based on radio physical layer channel characteristics quantifies machinery of consultation, it is characterised in that includes as follows Step：

Step 1：The advance collection communication data message of both sides of data communication：Both sides establish a kind of nothing with cross correlation first Line channel, is interacted within the set time, each obtains the number for sending fixed duration according to fixed transmission rate and being collected According to bag, the channel characteristic value in each packet is each extracted, a string is each formed and is used for the input data that key quantifies；

Step 2：Both sides' initialization key quantization parameter of data communication：Both sides each enter to the input data quantified for key Row segmentation, the datum mark of every section of initial packet are initialized as first data point of this section, and every section of grouping serial number is opened from 1 Begin, and slope threshold value is set；

Step 3：One side of data communication carries out Dynamic Packet slope quantization successively to every one piece of data after segmentation：

3.1 data communication a side choose the first segment data, since the datum mark of this section, by data point afterwards successively with base It is compared on schedule, if the absolute value of the difference of current data point and datum mark is more than slope threshold value, carries out key quantization, A bit is generated, and records the terminal that current data point is current group, data point subscript is stored in the lower mark of packet In record, grouping serial number increase by 1, the datum mark of next packet is the terminal of a upper packet；Otherwise give up the data point, carry out down The comparison of one data point, until terminating the packet generates a bit；This process completes the bit quantization of a packet；

One side of 3.2 data communication will carry out Dynamic Packet quantization, a group quantization according to step 3.1 successively to the segment data One and only one bit is generated, the bit that each group quantization is generated is stored in quantization bit string successively, if For quantization bit string for sky, then a bit being currently generated is quantization bit string；Otherwise a bit of generation is spelled Quantization bit string afterbody is connected to, the packet bit that this process completes one piece of data quantifies；

One side of 3.3 data communication carries out bit quantization, each section will obtained after quantization to every one piece of data according to step 3.2 Quantization bit string has carried out splicing generation original quantisation key successively, obtains key quantized result, i.e., original quantisation key and point Group subscript record；

Step 4：The both sides of data communication carry out cipher key agreement process according to packet subscript record with giving up array, specifically consult Journey includes：

Packet subscript record in key quantized result is sent to the opposing party by one side of 4.1 data communication；

After the opposing party of 4.2 data communication receives the packet subscript record of other side, oneself is used for according to packet subscript record The input data that key quantifies carries out packet key quantization successively, records the packet subscript if current group is without generation bit In array is given up；Otherwise the bit of generation is stored in quantization bit string, if quantization bit string is sky, works as previous existence Into a bit be quantization bit string；Otherwise a bit of generation is spliced to quantization bit string afterbody, quantified The opposing party has obtained key quantized result after end, i.e., quantization bit string will give up array transmission with array, the opposing party is given up To other side, the quantization bit string quantization key final as the opposing party；

4.3 data communication other side receive the opposing party give up array after, it is close to oneself original quantisation successively according to array is given up Respective packets quantization bit in key is given up, and obtains final quantization key, completes both sides' cipher key agreement process；

Step 5:The key of the both sides of data communication quantifies negotiations process and terminated, and both sides, which each obtain a string, has safe enough length 128-256bit 01 bit key stream is spent, quantifies to realize wireless secret communication in the environment of arranging key herein.

2. a kind of dynamic key based on radio physical layer channel characteristics according to claim 1 quantifies machinery of consultation, its It is characterised by, the slope threshold value in step 2 is determined by parameter elps and fluctuation parameters d, and the definition of slope threshold value (cmp) is Cmp=elps/d, wherein parameter elps are defined as critical value, and difference is averaged between all consecutive number strong points in one piece of data Value, value 2-4, fluctuation parameters d are used for reducing influence of the less fluctuation to key generation, value 0.5-1.

3. a kind of dynamic key based on radio physical layer channel characteristics according to claim 1 quantifies machinery of consultation, its Be characterised by, during one bit of generation described in step 3.1, if specifically, the difference of current data point and datum mark for just, Then the group quantization bit is 1；If the difference of current data point and datum mark is negative, the group quantization bit is 0.

4. a kind of dynamic key based on radio physical layer channel characteristics according to claim 1 quantifies machinery of consultation, its It is characterised by, the absolute value of the difference DELTA of current data point and datum mark described in step 3, is defined as | Δ |=| array [i]-array [start] |, wherein array arranges for input data, and i is current data point subscript, and start is current group benchmark Point.

5. a kind of dynamic key based on radio physical layer channel characteristics according to claim 1 quantifies machinery of consultation, its It is characterised by step 4 that grouping information is recorded in packet following table record array segment, what each element therein preserved is The terminal subscript being each grouped, the number for packet preserved in segment [0]；Give up each element in array UB to preserve Be each terminal subscript for giving up packet, what is preserved in the UB [0] is the number for giving up packet.