WO2011023129A1

WO2011023129A1 - Method and equipment for ensuring communication security

Info

Publication number: WO2011023129A1
Application number: PCT/CN2010/076417
Authority: WO
Inventors: 戎璐; 梁文亮; 吴建军; 卢磊; 黄罡
Original assignee: 华为技术有限公司
Priority date: 2009-08-27
Filing date: 2010-08-27
Publication date: 2011-03-03
Also published as: CN101998390A; CN101998390B

Abstract

A method and equipment for ensuring communication security are provided. The method includes: both sides of communication of a wireless link estimating wireless channel respectively; extracting scheduled quantity of channel information respectively from the respective estimated result of channel; both sides of communication or either side coding a part or all of the locally extracted channel information, and sending the coded channel information to the other side; both sides of communication or either side performing error correcting on the locally extracted channel information according to the received coded channel information, and obtaining the channel information correspond to the other side; both sides of communication generating a shared cryptographic key utilizing the locally extracted channel information and the obtained channel information by error correcting respectively, or either side generating the shared cryptographic key utilizing the locally extracted channel information, the other side generating the shared cryptographic key utilizing the obtained channel information by local error correcting; utilizing the shared cryptographic key to carry out encrypted communication. Utilizing the method may improve the security of wireless communication system.

Description

Method and device for ensuring communication security The application is submitted to the Chinese Patent Office on August 27, 2009, and the application number is 200910171251. 5. The invention name is "Method and Equipment for Secure Communication", and submitted on October 16, 2009. The Chinese Patent Office, Application No. 200910178333. 2. The priority of the present invention is the priority of the Chinese Patent Application, which is incorporated herein by reference. TECHNICAL FIELD The present invention relates to communication technologies, and in particular, to a method and device for ensuring communication security.

BACKGROUND OF THE INVENTION The security systems of existing communication systems are mostly based on modern cryptography, and the complexity of the operation is used to prevent the key from being deciphered in a limited time, thereby achieving relative security. However, the development of cryptography has led to the discovery of security vulnerabilities in key algorithms, and the computational complexity required to decipher keys has gradually decreased. At the same time, the increased computing power of the network has made it necessary to decipher the keys. It is getting shorter and shorter. Therefore, people have to find more secure and reliable technical solutions.

The wireless communication system has a broadcast characteristic due to its electromagnetic propagation, and the security problem is more prominent. With the further development of the breadth, depth and personalization of wireless communication, people's dependence on wireless communication and its security will be further enhanced. Therefore, it is necessary to find a more powerful wireless communication security solution.

At present, the academic community is studying the physical layer security in wireless communication, and expects to provide additional security for the wireless link through the signal processing technology of the physical layer to prevent the user's wireless signal from being eavesdropped. The basic scheme is to use the multi-antenna air separation capability to suppress the detection of user signals by eavesdroppers to improve the security of the wireless link.

However, the various solutions proposed in the current physical layer security literature are basically based on the premise that the system can predict the eavesdropper channel, but in actual systems, it is difficult to know the location of the eavesdropper, the number of receiving antennas, and the channel. Information, even difficult to know whether the eavesdropper exists, so it is difficult to achieve in the actual system. Moreover, the existing solution assumes that the eavesdropper is difficult to demodulate and decode effectively at a low SNR, using general hardware complexity, without fully considering that the professional eavesdropper can have more powerful terminal hardware and software processing than the average user. The ability to achieve signal detection at a much lower signal-to-noise ratio than the average user, so this type of solution provides less security. SUMMARY OF THE INVENTION Embodiments of the present invention provide a method and a device for ensuring communication security, which improve the security of a wireless communication system without relying on assumptions such as predicting eavesdropper information.

Embodiments of the present invention provide a method for ensuring communication security, including:

The two sides of the communication of the wireless link perform wireless channel estimation separately;

The communication parties respectively extract a predetermined number of channel information from respective channel estimation results; the communication parties or one of the parties encodes part or all of the locally extracted channel information, and transmits the encoded channel information to the other party. ;

The communication party or one of the two parties corrects the locally extracted channel information according to the received coded channel information, and obtains channel information that is consistent with the other party;

The communication parties respectively generate the shared key by using the locally extracted channel information and the channel information obtained after error correction, or one of the parties uses the locally extracted channel information to generate a shared key, and the other party obtains the local error correction. Channel information generates a shared key;

Encrypted communication is performed using the shared key.

The embodiment of the invention provides a wireless communication device, including:

a channel estimation unit, configured to perform wireless channel estimation;

An information extracting unit, configured to extract a predetermined number of channel information from the channel estimation result;

a key generating unit, configured to generate a shared key by using the extracted channel information;

And an encryption unit, configured to perform encrypted communication by using the shared key.

The method and device for ensuring communication security provided by the embodiments of the present invention use the reciprocity of the wireless channel to generate private information that is not known to the eavesdropper on both ends of the link without relying on the assumption of the eavesdropper information. Establishing a secure shared key enhances the security of the wireless communication system. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flowchart of a method for ensuring communication security according to an embodiment of the present invention;

2 is a schematic structural diagram of a wireless communication device according to an embodiment of the present invention;

3 is another schematic structural diagram of a wireless communication device according to an embodiment of the present invention;

4 is another schematic structural diagram of a wireless communication device according to an embodiment of the present invention;

FIG. 5 is another structural schematic diagram of a wireless communication device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS In order to make those skilled in the art better understand the solutions of the embodiments of the present invention, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

As shown in FIG. 1 , it is a flowchart of a method for ensuring communication security according to an embodiment of the present invention, which includes the following steps: Step 101: A communication channel of a wireless link separately performs wireless channel estimation.

Both sides of the communication of the wireless link can perform wireless channel estimation at the same or similar time-frequency positions, and support as much independent channel information as possible in order to consume as little time-frequency resources as possible, according to coherent bandwidth and coherence. Time optimizes the selection of the time-frequency position. Specifically, the selected adjacent time-frequency locations may be made larger than the coherence bandwidth and the coherence time. The coherence bandwidth is a specific frequency range within which the channel response at two different frequencies has a strong amplitude dependence. The coherence time is a specific time range in which channel responses at two different times have a strong amplitude dependence.

For some communication systems with radio resource management functions, the system may perform appropriate radio resource scheduling, such as periodically allocating uplink sounding reference signal resources in the cellular network, so that the communication parties perform channel estimation according to the reference signal. In addition, if the two parties communicate, the signal transmitted by the two parties can also be used to complete the channel estimation, thereby saving radio resource overhead.

In practical applications, the specific channel estimation process may use some existing algorithms, such as LS (Least Square) channel estimation algorithm, MMSE (Minimum Mean Square Error) channel estimation algorithm, and the like.

Step 102: The communication parties respectively extract a predetermined amount of channel information from respective channel estimation results.

A certain number of quantization bits can be extracted from the result of the channel estimation, and the format of the quantization bits can be a binary hard bit or a real bit or a fixed-point type soft bit.

The fixed point type is a data type, such as a real number π = 3. 14159265......, it is impossible to store accurately in an actual system, and in a wireless communication system, it is not allowed to consume a large amount of air resources in order to transmit the real number, so it is necessary to use Use as few bits as possible (such as 16 bits, 10 bits, 8 bits, etc.) to represent this real number. The exact number of bits is sufficient, depending on the results of the fixed-point simulation. The soft bits are distinguished from the hard bits of the value {0, 1}. In the theoretical analysis, the value is an infinitely accurate real number. In the engineering implementation, the value is a sufficiently accurate fixed point type. The real number on which soft bits are based is related to the specific method of soft decision. For example, a positive number is used to represent 1 and a negative number is used to represent 0. The larger the positive number, the greater the probability that the bit is 1 and the absolute value of the negative number is greater. The greater the probability that the bit is 0, if the soft bit is 0, the probability that the bit is 1 and 0 is half. Codewords that can be iteratively decoded, such as convolutional codes, are used The soft bit is decoded to obtain better performance than hard bit decoding.

The channel information may be extracted from any one or more of the following variables: channel phase, channel fading amplitude, higher order moment of the frequency selective channel, or parameters after discrete cosine transform. The ideal channel information is changed rapidly with geographic location and time to prevent the eavesdropper from getting a channel channel that is closely related to the user.

Step 103: The two or one of the communication parties encode part or all of the locally extracted channel information, and send the encoded channel information to the other party.

Step 104: The communication parties or the parties perform error correction on the locally extracted channel information according to the received coded channel information, to obtain channel information consistent with the other party.

The communication party or one of the parties encodes part or all of the locally extracted channel information, and transmits the encoded channel information to the other party, so that the other party corrects the locally extracted channel information according to the received coded channel information. .

In order to increase the flexibility of the method of the embodiment of the present invention, parameters required for quantifying channel information (refer to relevant parameters used when quantifying channel information extracted from the physical layer), coding parameters, chiseling The hole parameter, the shared secret information generation matrix parameter, and the like are sent to the other party, so that the other party performs correct decoding on the received coded bits according to the parameters. Of course, in order to simplify the implementation process, the two parties can pre-agreed these parameters.

In a specific implementation, the channel information may be encoded by using an existing system code encoder, and only some transformation of the encoded non-system bits or non-system bits may be output. The system code encoder is an encoder that includes all input bits in the output bits, that is, an encoder that directly inputs the input bits as part of the output bits. For example, input 3 bits bb ₂ , b ₃ , output 6 bits bb ₂ , b ₃ , b, +b ₂ , b ₂ + b ₃ , b, +b ₂ + b ₃ at a coding rate of 1/2 A linear block code encoder is a system code encoder. .

The encoded bit information sent through the wireless channel can be used as a layer of data, and the corresponding layer is encapsulated and processed, for example, as MAC (Media Access Control) layer data, via CRC (Cycl) The ical Redundancy Check, the checksum supplement and the physical layer channel coding are sent and processed, and HARQ (Hybrid-Auto Repeat Request) retransmission can be used to protect the other party. Can receive it correctly.

When both sides of the communication perform error correction on the locally extracted channel information, the quantized bits extracted by the local and the encoded bit information received from the other party may be decoded to obtain the same quantized bits. .

Correspondingly, a system decoder may be used, and the locally extracted quantization bits are used as the encoded system bits, and the encoded bit information received from the other party is used as a non-system bit, and the quantization corresponding to the other party is obtained through decoding. Bits, the specific process will be described in detail later. Step 105: The communication parties respectively generate a shared key by using the locally extracted channel information and the channel information obtained after error correction, or one of the nodes uses the channel information extracted by the wood ground to generate a shared key, and the other party utilizes the local The channel information obtained after error correction generates a shared key.

Step 106: Perform encrypted communication by using the shared key.

In the above step 105, when generating the shared key, the communication channel may first generate and extract the channel information and correct the error by using the extracted channel information and/or the channel information obtained after the error correction. The obtained channel information independently shares the private information, so that the eavesdropper cannot obtain any useful information about sharing the private information between the two communicating parties from the encoded bit information transmitted by the wireless channel. information.

The so-called shared private information is independent of the channel information, which means that the cross-correlation between the two sets of information is zero. For example, where the group information consists of the bit sequence a 3⁄4, . . . , and the group information consists of the bit sequence 1^, 13 ₂ , . . . , 13„, then for any i (wide m) and j ( Γη) are independent of each other between _ai and 1^.

If you mathematically define the above independent concept, you can define it as follows: Let the value space of the random variable a be A, and the value space of the random variable b be B, if the conditional probability P {a=a' | b= b' } =P {a=a' } for any a' belonging to A and b' to B, the conditional probability P {b=b' I a=a' } =P {b=b' } For any a' belonging to A and b' to B, the values are equal, then the random variable a and the random variable b are independent of each other. For example, the result of the first coin drop is half the probability of the front and the back: P {a=0} =0. 5, P {a=l} =0. 5, if you don't know the result of the first coin, but only Knowing that the result of the second coin drop is b=0 or b=l, then the result of the first coin drop cannot be guessed accordingly: P {a=0 | b=0} =P {a=0 | b= l} =0. 5=P {a=0}, P {a=l | b=0} =P {a=l | b=l} =0. 5=P {a=l}.

It should be noted that when the communication partners generate the shared private information, all the required shared private information can be obtained by performing the above steps 101 to 104, that is, the channel information extracted by one of the parties is performed. The encoding and transmitting the encoded channel information, the channel information quantization parameter, and the like (including a coding code parameter, a puncturing parameter, a shared private information generation matrix parameter, etc.) information to the other party. In this way, the party only needs to generate the shared private information according to the locally extracted channel information, and the other party needs to correct the locally extracted channel information according to the received encoded channel information, and obtain channel information consistent with the other party. Then, the error-corrected channel information is used to generate shared private information.

In addition, the communication parties can also decompose the extracted channel information into multiple parts, and by performing the processes of steps 101 to 104 multiple times, each time using the different channel information parts that are decomposed, different private information is obtained. Part, then combine multiple different pieces of private information into complete shared private information. If the processes of the above steps 101 to 104 are performed a plurality of times, different encoding/decoding/shared private information generating methods may be used each time, and the different channel information portions that are decomposed may be error-corrected by the communication parties respectively. For example, let the communication parties A and B transmit the encoded bit information through the wireless channel in turn. After generating the complete shared private information, the communication parties respectively use the shared private information to independently generate the shared key.

Specifically, in order to reduce the complexity of the operation, the shared private information may be directly used as the shared key; the shared private information may also be used as a random number input, an initialization vector input, or a numerical input in the key update algorithm (ie, using Add one number of 1 at a time), etc., to synthesize some other auxiliary information, such as upper key or existing key, record value, MAC address, serial number of data packet, cell identity, link-related identifier, historical data record Etc., generate a shared key. These auxiliary information can be saved locally.

Appropriate values of the initialization vector can ensure that the generated shared key does not overlap with the historical shared key. The initialization vector can be generated in various ways, one of which is a counter that is incremented by one use, and the NAS used in key generation in the existing LTE (Long Term Evolution) system. (Non-Access Stratum, non-access stratum) Upstream value NAS Uplink Counter is similar.

It should be noted that, between the foregoing steps 105 and 106, the method further includes the following steps: the two communicating parties respectively verify the shared key generated by the other party; and after performing the verification, step 106 is performed. Specifically, after the communication parties respectively generate the shared key, the generated shared keys can mutually confirm each other through a certain handshake signaling. After the handshake confirmation is successful, the shared key can be used for secure encrypted communication. The specific handshake confirmation process is similar to that in the prior art and will not be described in detail herein. If the handshake confirmation fails, the communicating parties need to return to step 101 to re-establish the key establishment process from the wireless channel estimation to the signaling handshake acknowledgement. However, in the new key establishment process, the communication parties can respectively treat the shared private information bits locally generated in the last key establishment process, or an equal number of locally extracted bits, as part of the obtained channel information bits. With the use, only the missing number of channel information bits is supplemented by the new radio channel estimate, so that the number of radio channel estimates required in the new key establishment process can be significantly reduced.

It can be seen that the method for ensuring communication security provided by the embodiment of the present invention can utilize the reciprocity of the wireless channel without relying on the assumption of the information of the eavesdropper, that is, when the two sides of the wireless communication perform two-way wireless communication, the two sides receive the signal. The experienced channel has a strong correlation. In an ideal situation, it can be assumed that the channels in the two directions are completely equal, and private information that cannot be learned by the eavesdropper is generated at both ends of the link, and a secure shared key is established. Thereby improving the security of the wireless communication system. In the embodiment of the present invention, the process of correcting channel information and generating shared private information may be implemented based on a plurality of methods, for example, based on a convolutional code and based on a linear block code.

The following assumes that the two sides of the communication are A and B respectively, and the parts of the radio channel information quantization bits extracted by the local physical layer from A and B are respectively required to be processed: l3⁄4 (m) and b _B (m), m=l, 2 , ..., L, where 13⁄4 is a hard bit, and b _B is a soft bit and a hard bit, respectively, and the above process will be described in detail. Example 1: Based on the implementation process of a convolutional code, in this embodiment, b _B is a soft bit.

A takes the L bits b _A extracted from the physical layer of the wood as input, first encodes the 1/1 convolutional encoder with the generator matrix G=[g, g ₂ ... gj, and obtains the encoded L bits 0^ , m=l ₎ 2, - , L o Then, for the encoded L bits d, ,, use the puncturing matrix P to punctify, and the K bits obtained after puncturing d _A1 (m), m= l, 2, -, Κ, as output, d send d _U (m) to Α over the wireless channel.

Α Using the encoded L bits ^0^ as input, use the puncturing matrix 1-P to punctify, and obtain the L-K bits d, after the puncturing. (m), m=l, 2, ~, L-K, output as shared private information.

The above two processes can also be implemented by merging simplification: using the bit value in the puncturing matrix P as a switching switch for two-way shunting, one way corresponding to the element equal to 1 in the matrix P, and the bit information d to be sent to B after output encoding _U (m) , the other 'channel corresponds to the element equal to 0 in P, and the output shares the private information d, . (m). Considering the transmission error, assume that the K bits received by B are d' _A1 . First, the soft information of the received K bits d' _A1 is de-punctured using the puncturing matrix P to obtain L soft bits d' _A . Then, B combines the L soft bits b _B extracted by the local physical layer and the L soft bits d′ after de-puncturing, according to the system bit of the systematic convolutional code encoder and the output order of the non-system bits. 2L encoded soft bits, as input to the system convolutional code decoder, are decoded by a 1/2 convolutional code decoder whose generator matrix is G'= ¹ ° "' °, and output L translations. After the code...

Bits b' , , (m) , m=l, 2,..., L.

B takes the L decoded bits b' _A as input, first encodes with a 1/1 convolutional encoder whose generator matrix is G=[ _gl g ₂ ... gj, and obtains the encoded L bits d' _A (m ), m=l, 2, "*, L. Then, after encoding the L bits d', , use the perforation matrix 1-P to punctify, and the LK bits d' obtained after the puncturing , (m), m-1, 2, -, LK, output as shared private information.

Example 2: A linear block code based implementation process, in this embodiment, b _B is a hard bit.

Let the generator matrix of the (N, L) system linear block code encoder corresponding to the encoder used by A (that is, the encoder input L bits, output N bits) be: G _sys = [I, G] , where I For the L-dimensional unit matrix, G = [g, g ₂ ... g _{x -} J , gi is a column vector with L elements, N < 2L.

A takes the L bits b _A extracted by the local physical layer as input, encodes with a linear block code encoder whose generation matrix is G, and outputs the encoded NL bits d _A (m), m-1, 2, -, Ν-L, then send d _A (m) to B over the wireless channel.

A selects 2L-N column vectors 1^ r ₂ ... r which are linearly independent from _§1 g ₂ ... in the k-dimensional space to form a key generation matrix R = [r, r ₂ ... r such that [GR] constitutes L-dimensional full Rank matrix. Then, the L bits b extracted by the local physical layer are used as input, and the code is obtained by using a linear block code encoder whose generation matrix is R. 2L-N bits q,, (m), m=l, 2, ···, 2L_N, are output as shared private information.

B is the L bits b _B extracted by the wood physical layer and the NL bits d′ received by the solution, as two inputs of the decoder, first according to the output order of the system bits and non-system bits of the system linear block code encoder , merged into N encoded bits. Then, the N coded bits are used as the input of the system linear block code decoder, and the (N, L) system linear block code decoder with the generator matrix is G _sys is decoded, and the L decoded bits are output. b' _A (m), m=l, 2, ···, L.

Then, B takes L decoded bits b' _A as input, and encodes with a linear block code encoder whose generation matrix is R, and encodes 2L-N bits q' _Λ (ηι), m=l, 2, ···, 2L_N, output as shared private information.

As a special case, when the column vectors constituting the key generation matrix R satisfy the following relationship: (1) the sum of all the elements of each column vector ri is equal to 1; (2) any two column vectors ^ and r" Satisfying ι··”=0, the generated shared keys q,, (m), and q′ _Λ (m) are 2L_N bits of the L bits 126 and b _B extracted locally by the communication parties.

Example 3: Implementation process based on Turbo code.

Suppose A is locally extracted L=2W bits b,, (l), b, (2), ···, b,, (2W) are encoded by 1/2 Turbo encoder, the first component encoder The generator matrix is [11], and the output of the inner interleaver is 13⁄4^+1), b, (l), b, (W+2), b, (2), ···, b, (2W), b, (W), the generator matrix of the second component encoder is [1 1], and the encoder output is truncated, then the two outputs of the Turbo encoder can be represented as b, (l), b, (l)+b,(2), b,(2)+b,(3), ···, b,(2W-l)+b,(2W) and b,(W+l), b , (W+l)+b, (l), b, (l) +b, (W+2) , b _A (W+2) +b _A (2), · · ·, b _A (2W) +b _A (W). For the coded bits, the chiseling matrix P=[1 0; 0 0] of 2 rows and 2 columns is used for puncturing, and the W bits obtained after the puncturing are b, (l), b, (2) + b , (3), b, (4) + b, (5), ..., b _A (2W-2) + b _A (2W - 1) are sent to B.

A uses the puncturing matrix Q=[0 0; 1 0] to punctify the encoded bits, and the W bits obtained after puncturing, (W+1), b, and (1) +b, , (W+2), b,, (2) +b, (W+3), ···, b,, (Wl) +b, and (2W) are shared private information.

B de-puncturing the received bits with the puncturing matrix P; decoding the locally extracted bits and the punctured bits by a 1/3 convolution decoder to obtain decoded bits, The decoded bit acts as channel information consistent with the other party. Then, the obtained decoded bits are encoded by a 1/2 convolutional encoder, and the coded bits are punctured using a puncturing matrix Q, and bits obtained after puncturing are used as shared secret information. Wherein, the puncturing matrices P and Q are matrixes of M rows and D columns (if in application, the number of columns of P and the number of columns of Q are different, the same number of columns can be obtained by cyclic expansion. The hole matrix P, = [PP~P] and Q, = [QQ ... Q], the number of columns D is the least common multiple of 3⁄4 and 3⁄4, and satisfies the following relationship:

For any i and j, satisfy P(i, j)*Q(i, j)=0;

The sum of all elements of matrix P, plus the sum of all elements of matrix Q, is equal to D. Conventional encoders are used extensively for channel coding with proven error correction capabilities. Specifically, for k input bits, the encoders of n output bits have their input bits bb ₂ , ···, b _k , and the output bits are dd ₂ ,..., d„, after passing through the channel, due to noise And the influence of detection errors, etc., the received bits d ' „ d ' ₂ , ..., d ' „ may have multiple bit errors and errors with dd ₂ , ..., d „ incomplete, and the receiving end translates The code can correct most of the errors and recover the original input bits, ie the output of the decoder b ' „ b ' ₂ , ···, b ' _{k can,} in most cases, be implemented with the transmitting end bb ₂ , ..., b _k consistent.

In the embodiment of the present invention, the system code is used. If the same (n, k) encoder is used, then among the n output bits dd ₂ , ···, d _n , there are k bits and input bits bb. ₂ , ···, b _{k is} exactly the same, without loss of generality, let db,, d ₂ =b ₂ , ..., d _k =b _k . What is transmitted in the air is the additional nk coded bits d _k+1 , d _k+2 , ..., d„ after removing the system bit outputs dd ₂ , ..., d _k . After over-the-air transmission, due to wireless transmission Under the influence of ideal factors, the corresponding bits received by the receiving end are d ' _k+1 , d' _k+2 , ···, d' „ There may be multiple bits due to an error and d _k+1 , d _{k +2} , ..., d„ are not completely consistent. At the same time, although the receiving end shares the same physical channel with the transmitting end, the locally extracted physical layer channel information b is affected by non-ideal factors such as noise and channel estimation error. _{'"b' 2, ···,} b 'k transmitting side physical layer extracted channel information bb _2, ···, b _k is not exactly the same. The decoder input bits d ' „ d' ₂ ,..., d ' „ (where d, , =b ' „ d ' ₂ =h' ₂ ,...: d, _k =b, _k ), It is not completely consistent with the output of the encoder encoder output bits dd ₂ , ···, d _n by the non-ideal factors in the wireless communication. The embodiment of the present invention utilizes the error correction capability of the conventional codec to enable the receiving end to Correct most of the errors and recover the original input bits, ie the output b ' „ b ' ₂ , ..., b ' _{k of the} decoder can, in most cases, be implemented with the transmitting terminals bb ₂ , ..., b _k Zhizhi.

In the above example 1, the information of K bits obtained by puncturing the extracted L bits is transmitted over the air, and the information of LK bits is generated when generating the private information, that is, the shared secret generated by the communication parties. The key information is completely independent of the error correction information transmitted over the air to help the two parties obtain the reciprocal information, thereby ensuring the security of the shared key.

In the above example 2, the selection of R has the feature: [G, R] constitutes a full rank square matrix. This feature guarantees that each column of G and R is linearly independent, and the L NL L-dimensional column vectors of G and the 2L-N L-dimensional column vectors of R together form L mutual mates of L-dimensional space. Independent coordinate axis. Therefore, any L input bits can be represented by the L column vectors as coordinate axes and represented as an L-dimensional coordinate. For an eavesdropper, even if he knows the NL coordinate values in the L-dimensional coordinate system, he cannot know any information about calculating the coordinate values on the 2L-N coordinate axes. This is like having a point (N=3) in 3D space, mapping it into a 3D coordinate system, getting a set of coordinate values {x, y, z}, and then taking two of the coordinate values {y, z} While sending to the other party (L=l, NL=2), although the eavesdropper can hear the {y, z} of the air transmission, it is impossible for him to obtain any information about another coordinate value X accordingly. In the above example 3, the L/2 bits b, (l), b, (2) + b, (3), b, which are obtained by encoding and puncturing the extracted L bits, are transmitted over the air. (4) +b, (5), ···, b, (2W-2) +b, (2W_ l) information, and the private information is generated using a different L/2 bits b _A (W+l) , b _A (l) +b _A (W+2) , b _A (2) +b _A (W+3) , ···, b,, (Wl) +b,, (2W The information, and it is easy to infer that the total of L bits are completely independent, thereby ensuring the security of the shared key.

It can be seen that the method of the embodiment of the present invention fully considers the non-ideality of the actual system in the utilization of the reciprocity of the wireless channel, such as a large number of channel information estimation errors, by clever coding, decoding, and sharing of the private information generation process. On the one hand, it can correct the inconsistent channel reciprocity information obtained by most of the links, thereby ensuring the availability of the technical solution of the present invention in the actual system environment; on the other hand, the shared key information generated by the communication parties can be guaranteed. It is completely independent of the error correction information transmitted through the air to help the two parties obtain the reciprocal information, thereby ensuring the security of the technical solution of the present invention in the actual system environment.

A person skilled in the art can understand that all or part of the steps of implementing the above embodiments can be completed by a program instructing related hardware, and the program can be stored in a computer readable storage medium, the storage. Media, such as: R0M/RAM, disk, CD, etc.

The embodiment of the invention further provides a wireless communication device, as shown in FIG. 2, which is a schematic structural diagram of the device.

In this embodiment, the device includes:

The channel estimation unit 201 is configured to perform wireless channel estimation. Specifically, the wireless channel estimation may be performed at the same or similar multiple time-frequency positions, and the selected adjacent time-frequency positions are greater than the coherence bandwidth and the coherence time.

The information extracting unit 202 is configured to extract a predetermined number of channel information from the channel estimation result. Specifically, the channel information may be extracted from any one or more of the following information: channel phase, channel fading amplitude, and frequency selectivity. The higher order moment of the channel or the discrete cosine transformed parameter, the channel information may be expressed as: a binary hard bit, or a real number, or a soft bit of a fixed point type.

The key generation unit 203 is configured to generate a shared key by using the extracted channel information.

The encryption unit 204 is configured to perform encrypted communication by using the shared key.

A preferred structure of the key generation unit includes: a shared private information generation subunit 231 and a shared key generation subunit 232. among them:

The shared private information generating subunit 231 is configured to generate shared private information, where the shared private information is independent of the channel information;

The shared key generation subunit 232 is configured to generate a shared key by using the shared secret information.

In an actual application, the key generation subunit 232 may directly use the shared private information as a shared secret. The key may also generate the shared key by using the shared private information and some auxiliary information. The auxiliary information may be one or more of the following information stored in the wood: an upper layer key, a recorded value, a cell identifier, a link related identifier, and a historical data record.

In the embodiment of the present invention, the device may be any party of the communication parties.

As shown in FIG. 3, in another embodiment of the present invention, the device may further include: an encoding unit 301 and a sending unit 302. The encoding unit 301 is configured to encode part or all of the locally extracted channel information, and the sending unit 302 is configured to send the encoded channel information to the other party, so that the other party can receive the encoded channel according to the received channel. The information corrects the locally extracted channel information. In addition, the transmitting unit 302 may further transmit information such as channel information quantization parameter, coding and decoding parameter, puncturing parameter, and shared private information generation matrix parameter to the other party, so that the other party performs correct decoding and the like by using the parameter.

As shown in FIG. 4, in another embodiment of the present invention, the device further includes: a receiving unit 401 and an error correcting unit 402. The receiving unit 401 is configured to receive the encoded channel information sent by the other party, and the error correcting unit 402 is configured to perform error correction on the locally extracted channel information according to the encoded channel information received by the receiving unit 401. , get the channel information consistent with the other party.

In this embodiment, the key generation unit 203 is further configured to generate a sharing key according to the channel information obtained after the error correction.

Certainly, the wireless communication device of the embodiment of the present invention may further have various modifications. For example, in another embodiment of the present invention, the device may further include the foregoing coding unit 301, the sending unit 302, and the receiving unit. 401 and error correction unit 402.

In the wireless communication device of the embodiment of the present invention, the process of correcting the channel information and generating the shared secret information may be implemented based on a plurality of methods, for example, based on a convolutional code, a linear block code based, and a Turbo code based.

When the implementation is based on a convolutional code, the coding unit is specifically configured to encode part or all of the locally extracted channel information by using a 1/1 convolutional encoder, and use the punctured matrix P for the encoded bits. The puncturing, the bit obtained after the puncturing is sent to the other party; the error correcting unit is specifically configured to use the puncturing matrix P to perform the puncturing on the received bit, and extract the locally extracted bit, and after the puncturing The bits are decoded by a 1/2 convolutional decoder to obtain decoded bits, and the decoded bits are used as channel information that is consistent with the other party; the shared private information generation subunit is specifically used The bit coded by the coding unit is punctured by using a puncturing matrix 1-P, and the bit obtained after puncturing is used as shared secret information; or the decoded bit obtained by the error correction unit is utilized 1/ A convolutional encoder performs coding, and the coded bits are punctured using a puncturing matrix 1-P, and bits obtained after puncturing are used as shared private information. For the detailed process, refer to the description in the previous example 1. When the implementation is based on a linear block code, the coding unit is specifically configured to use a generation matrix for some or all bits of the locally extracted channel information, such as L bits, to be 0=[g, g ₂ ... g , _gi for having L The column vector of the element, the linear block code encoder of N<2L is encoded, and the encoded NL bits are sent to the other party; the error correction unit is specifically configured to use the locally extracted L bits and the NL received by the solution. Combining the bits into N coded bits; using the N coded bits as the input of the system linear block code decoder, using a system linear block code decoder whose generator matrix is G _sys = [I, G] Decoding, outputting L decoded bits, using the decoded L bits as channel information of the other party; the shared private information generating sub-unit is specifically used for locally extracting L bits as Input, encoding using a linear block code encoder whose generator matrix is R=[r, r ₂ ... r -, ], using the encoded 2L-N bits as shared secret information; or outputting by the error correction unit The L decoded bits are used as inputs Is the generator matrix _{R = [r, r 2 ...} r of the linear block code encoder for encoding the encoded bits 2L_N as the shared secret information. For the detailed process, refer to the description in the previous example 2.

When the implementation is based on the Turbo code, the coding unit is specifically configured to encode the locally extracted L bits by using a 1/M convolutional encoder or a Turbo encoder, and chisel the matrix P by using the coded bits. The transmitting unit is configured to send the T bits obtained after the puncturing to the other party, where T<L; the error correcting unit is specifically configured to use the puncturing matrix P to solve the received bit. By puncturing, the locally extracted bits and the de-punctured bits are decoded by a 1/(M+1) convolutional decoder to obtain decoded bits, and the decoded bits are used as The shared secret information is generated by the unit, and is configured to perform puncturing using the punctured matrix Q for the bits encoded by the coding unit, and use the LT bits obtained after the puncturing as the shared private information; Or the decoded bits obtained by the error correction unit are encoded by a 1/M convolutional encoder, and the coded bits are punctured by using a puncturing matrix Q, and the bits obtained after puncturing are used as shared secrets. Information; The hole matrices P and Q are matrixes of M rows and D columns (if, in application, the number of columns of P and the number of columns of P are different, a perforation matrix P of equivalent identical number of columns can be obtained by cyclic expansion, = [PP~P] and Q, = [QQ ··· Q] , whose number of columns D is the least common multiple of D _P and D _Q ), and satisfy the following relationship: For any i and j, satisfy P (i, j) *Q (i, j) =0 ; The sum of all elements of matrix P, plus the sum of all elements of matrix Q, equals D. For the detailed process, refer to the description in the previous example 3.

FIG. 5 is another schematic structural diagram of a wireless communication device according to an embodiment of the present invention.

The difference from the embodiment shown in FIG. 2 is that, in this embodiment, the device further includes:

The verification unit 205 is configured to: before the encryption unit 204 performs the encrypted communication by using the shared key, verify the shared key generated by the other party, and after the verification is passed, instruct the encryption unit 204 to use the shared secret The key is encrypted and communicated, so that the accuracy of the shared key generated by both parties can be further ensured. Specifically, the verification unit 205 can confirm whether the shared key generation is successful through a certain handshake signaling and calculation; if successful, Transmitting the shared key to the encryption unit 204; if unsuccessful, obtaining the shared private information or an equal number of woodland extracted channel information as part of the predetermined number of channel information The channel information is notified, and the channel estimation unit 201 is notified to reacquire the channel information of the remaining portion through the new radio channel estimation.

It can be seen that the wireless communication device in the embodiment of the present invention fully considers the non-ideal factors existing in the actual system such as the estimation error of the channel information in the wireless channel reciprocity utilization, and generates the private information through smart coding, decoding, and sharing. The process, 'the aspect can correct the channel reciprocal information obtained by the majority of the links, thereby ensuring the availability of the technical solution of the present invention in the actual system environment; on the other hand, the sharing generated by the communication parties can be guaranteed The key information is completely independent of the error correction information transmitted over the air to help the two parties obtain consistent reciprocal information, thereby ensuring the security of the technical solution of the present invention in an actual system environment. The embodiments of the present invention have been described in detail above, and the present invention has been described with reference to the specific embodiments thereof. The description of the above embodiments is only for facilitating understanding of the method and device of the present invention. Meanwhile, it is generally known to those skilled in the art. The present invention is not limited by the scope of the present invention.

Claims

Rights request

A method for ensuring communication security, characterized in that it comprises:

A. The two sides of the wireless link perform wireless channel estimation separately;

B. The communication parties respectively extract a predetermined number of channel information from respective channel estimation results; C. the communication parties or one of the parties encodes part or all of the locally extracted channel information, and encodes the channel. The information is sent to the other party;

D. The communication parties or the parties perform error correction on the locally extracted channel information according to the received coded channel information, to obtain channel information that is consistent with the other party;

E. The communication parties respectively generate the shared key by using the locally extracted channel information and the channel information obtained by local error correction, or one of the parties uses the locally extracted channel information to generate a shared key, and the other party uses the local correction The channel information obtained after the error generates a shared key;

F. Perform encrypted communication by using the shared key.

2. The method according to claim 1, wherein the performing wireless channel estimation by each of the communication parties comprises: performing, by the communication parties, wireless channel estimation at the same or similar multiple time-frequency positions, respectively, and selecting the phase The time-frequency position of the neighbor is greater than the coherence bandwidth and coherence time.

3. The method according to claim 1, wherein the channel information comprises any one or more of the following:

Channel phase, channel fading amplitude, higher order moment of frequency selective channel or discrete cosine transformed parameters.

4. The method according to claim 1, wherein the format of the channel information is: a binary hard bit, or a real bit or a fixed bit type soft bit.

5. The method of claim 1 wherein:

The generating, by using the locally extracted channel information and the channel information obtained by the local error correction, the shared key includes: the communication parties respectively use the locally extracted channel information and the local error correction. The channel information generates shared private information, and the shared private information is used as the shared key;

The one party generates the shared key by using the locally extracted channel information, and the other party generates the shared key by using the channel information obtained by the local error correction, including: the one party generates the shared secret information by using the locally extracted channel information, and The shared private information is used as the shared key, and the other party generates shared private information by using channel information obtained by local error correction, and uses the shared private information as the shared key.

6. The method of claim 1 wherein:

The generating, by using the locally extracted channel information and the channel information obtained after the local error correction, the shared key includes:

The communication party generates the shared private information by using the locally extracted channel information and the channel information obtained by the local error correction respectively; generating the shared key by using the shared private information and the locally saved auxiliary information; The locally extracted channel information generates a shared key, and the other party generates the shared key by using the channel information obtained by the local error correction, including:

The method uses the locally extracted channel information to generate shared private information, and generates the shared key by using the shared private information and the locally saved auxiliary information; and the other party generates the shared private information by using the channel information obtained by the local error correction. And generating the shared key by using the shared private information and the locally saved auxiliary information.

The method according to claim 6, wherein the auxiliary information comprises one or more of the following: an upper layer key, an initial vector, a value, a MAC address, a serial number of the data packet, a cell identifier, and a chain. Road related signs, historical data records.

8. Method according to claim 5 or 6, characterized in that

The encoding the locally extracted channel information, and transmitting the encoded channel information to the counterpart includes: encoding the locally extracted bits by using a 1/1 convolutional encoder, and using the perforation matrix P for the encoded bits. Perform a boring to send the bits obtained after the boring to the other party;

And performing error correction on the locally extracted channel information according to the received encoded channel information, to obtain channel information consistent with the opposite party, including:

Using the puncturing matrix P for the received bits to perform the puncturing;

The locally extracted bits and the de-punctured bits are decoded by a 1/2 convolution decoder to obtain decoded bits, and the decoded bits are used as channel information that is consistent with the other party;

The one party generates the shared key by using the locally extracted channel information, and the other party generates the shared private information by using the channel information obtained by the local error correction, including:

The square side uses the puncturing matrix 1-P to punctify the coded bits, and uses the bits obtained after puncturing as the shared secret information;

The other party encodes the obtained decoded bits by a 1/1 convolutional encoder, and punctured the encoded bits by using a puncturing matrix 1-P, and uses the bits obtained after puncturing as a shared secret. information.

9. A method according to claim 5 or claim 6 wherein: The encoding the locally extracted channel information, and transmitting the encoded channel information to the other party includes: using a generation matrix for the locally extracted L bits, 0 = [g, g ₂ ... g^], and _gi is L Column vector of elements, N<2L linear block code encoder encodes, and sends the encoded NL bits to the other party;

Combining the locally extracted L bits and the NL bits received by the solution into N coded bits; using the N coded bits as the input of the decoder, using the generator matrix as G _sys = [I, G] The system linear block code decoder performs decoding, outputs L decoded bits, and uses the decoded L bits as channel information corresponding to the other party;

The one of the ones generates the shared key by using the locally extracted channel information, and the other party generates the shared private information by using the channel information obtained by the local error correction, including: the one of the locally extracted L bits is used as an input, and the generation matrix is used. For R = [r, r ₂ ...

The linear block code encoder performs encoding, and the encoded 2L-N bits are used as shared private information;

The other side uses the L decoded bits as an input, and uses a linear block code encoder whose generation matrix is R=[r, r ₂ ... r ₂ Lx] to encode, and 2L-N codes are encoded. Bits are used as shared private information.

10. Method according to claim 5 or 6, characterized in that

The encoding the locally extracted channel information, and transmitting the encoded channel information to the counterpart includes: encoding the locally extracted L bits by using a 1/M convolutional encoder or a Turbo encoder, and encoding the encoded The bit is punctured by the puncturing matrix P, and the T bits obtained after the puncturing are sent to the other party, where T<L;

Using the puncturing matrix P for the received bits to perform the puncturing;

The locally extracted bits and the de-punctured bits are decoded by a 1/(M+1) convolutional decoder to obtain decoded bits, and the decoded bits are matched with each other. Channel information

The method uses the locally extracted channel information to generate a shared key, and the other party generates the shared private information by using the channel information obtained by the local error correction, including:

One of the bits punctured the coded bit by using a puncturing matrix Q, and the L-T bits obtained after puncturing are used as shared private information;

The other party obtains the decoded bits by using a 1/M convolutional encoder, and encodes the encoded bits. The bit is punctured by the puncturing matrix Q, and the bits obtained after the puncturing are used as the shared secret information; the puncturing matrices P and Q are matrixes of M rows and D columns, and satisfy the following relationship:

For any i and j, satisfy P (i, j) *Q (i, j) =0;

The sum of all elements of matrix P, plus the sum of all elements of matrix Q, is equal to D.

The method according to claim 5 or 6, further comprising:

Before performing the encrypted communication by using the shared key, the two communication parties verify the shared key generated by the other party through handshake signaling;

After the verification is passed, the shared key is used for encrypted communication.

12. The method according to claim 11, further comprising:

If the verification fails, the shared private information or an equal amount of locally extracted channel information is used as channel information that has been obtained as part of the predetermined number of channel information, and the new wireless channel estimation is re-extracted by the new wireless channel estimation. The channel information of the remaining portion of the predetermined number of channel information is then returned to the step (.

13. A wireless communication device, comprising:

a channel estimation unit, configured to perform wireless channel estimation;

14. The apparatus according to claim 13, wherein the channel estimation unit specifically performs wireless channel estimation at the same or similar plurality of time-frequency positions, and selects adjacent time-frequency. The location is greater than the coherence bandwidth and coherence time.

The device according to claim 13, wherein the key generation unit comprises: a shared private information generation subunit, configured to generate shared private information;

a shared key generation subunit, configured to generate a shared key by using the shared secret information.

The device according to claim 15, wherein the shared key generation subunit is specifically configured to use the shared private information as a shared key, or use the shared private information and locally saved auxiliary The information generates a shared key.

The device according to claim 15, wherein the device further comprises:

a coding unit, configured to encode part or all of the locally extracted channel information;

a sending unit, configured to send the channel information encoded by the coding unit to the other party, so that the other party is connected The received coded channel information corrects the locally extracted channel information.

18. Apparatus according to claim 17 wherein:

The coding unit is specifically configured to encode part or all of the locally extracted channel information by using a 1/1 convolutional encoder, and use the puncturing matrix P to punctify the encoded bits;

The sending unit is specifically configured to send the bit obtained after the puncturing to the other party;

The shared private information generating sub-unit is specifically configured to perform puncturing using the punctured matrix 1-P for the coded bits of the coding unit, and use the bits obtained after puncturing as shared private information.

19. Apparatus according to claim 17 wherein:

The coding unit is specifically configured to use a generation matrix for the locally extracted L bits as G=[g, g ₂ ... g _x -J , _gi is a column vector with L elements, and a linear block code of N<2L Encoding

The sending unit is specifically configured to send the encoded N-L bits to the other party;

The shared private information generating sub-unit is specifically configured to use the locally extracted L bits as an input, and encode using a linear block code encoder whose generating matrix is R=[r, r ₂ ... r _2l −, ], and encode The latter 2L_N bits are used as shared private information.

20. Apparatus according to claim 17 wherein:

The coding unit is specifically configured to encode the locally extracted L bits by using a 1/M convolutional encoder or a Turbo encoder, and perform puncturing using the punctured matrix P for the encoded bits;

The sending unit specifically sends the T bits obtained after the puncturing to the other party, where T<L;

The shared private information generating sub-unit is specifically configured to perform puncturing using the punctured matrix Q for the bits encoded by the coding unit, and use the L-T bits obtained after puncturing as the shared private information.

The device according to claim 15 or 17, wherein the device further comprises: a receiving unit, configured to receive the encoded channel information sent by the other party;

An error correction unit, configured to perform error correction on the locally extracted channel information according to the encoded channel information received by the receiving unit, to obtain channel information that is consistent with the other party;

The key generation unit is further configured to generate a shared key according to the channel information obtained after the error correction.

22. Apparatus according to claim 21 wherein:

The error correction unit is specifically configured to perform puncturing using the puncturing matrix P for the bits received by the receiving unit, and extract the locally extracted bits and the punctured bits by using the 1/2 volume translation Decoding, obtaining a decoded bit, and using the decoded bit as channel information consistent with the other party; The shared private information generating sub-unit is specifically configured to encode the decoded bits obtained by the error correcting unit by using a 1/1 convolutional encoder, and perform the coded bits by using the puncturing matrix 1-P. The hole is cut, and the bit obtained after the hole is used as the shared secret information.

23. Apparatus according to claim 21 wherein:

The error correction unit is specifically configured to combine the locally extracted L bits and the NL bits received by the receiving unit into N coded bits; and the N coded bits are used as system linear block codes. The input of the _{coder is} decoded by a system linear block code decoder whose generation matrix is G _sys = [I, G], and L decoded bits are output, and the decoded L bits are used as the counterpart. 'Channel information;

The shared private information generating sub-unit is specifically configured to use the L decoded bits output by the error correcting unit as an input, and adopt a linear block code encoder whose generating matrix is R=[r, r ₂ ... r Encoding is performed, and the encoded 2L-N bits are used as shared private information.

24. Apparatus according to claim 21 wherein:

The error correction unit is specifically configured to perform puncturing on the received bits by using a puncturing matrix P, and locally extracting bits and de-punctured bits by using a 1/(M+1) convolution decoder. Decoding, obtaining decoded bits, and using the decoded bits as channel information that is consistent with the other party;

The shared private information generating sub-unit is specifically configured to encode the decoded bit obtained by the error correcting unit by using a 1/M convolutional encoder, and perform puncturing using the puncturing matrix Q for the encoded bit. The bits obtained after the puncturing are used as shared private information; the puncturing matrices P and Q are matrixes of M rows and D columns, and satisfy the following relationship: For any i and j, satisfy P (i, j) *Q (i, j) =0; the sum of all elements of matrix P, plus the sum of all elements of matrix Q, equal to D.

The device according to claim 15, wherein the device further comprises:

a verification unit, configured to: after the encryption unit performs encrypted communication by using the shared key, verify the shared key generated by the other party, and after the verification is passed, instruct the encryption unit to perform encryption by using the shared key Communication.

26. Apparatus according to claim 25, characterized in that

The verification unit is further configured to: after the verification fails, use the shared private information or an equal amount of locally extracted channel information as channel information that has been obtained as part of the predetermined number of channel information, and notify The channel estimation unit re-acquires channel information of the remaining portion of the predetermined number of channel information by new radio channel estimation.