CN103580849A - Spatiotemporal chaos secret communication method - Google Patents

Abstract

The invention discloses a spatiotemporal chaos secret communication method. The spatiotemporal chaos secret communication method comprises the steps that (1), the states of a space lattice of a one-way coupling image lattice system at a sending end are divided into odd-dimensional states and even-dimensional states, (2) displacement mapping iteration is carried out on a plaintext frame and vectors in the odd-dimensional states N times, (3) a transmission signal is obtained, (4) a driving signal of the one-way coupling image lattice system at the sending end is calculated, (5) a synchronizing signal of the one-way coupling image lattice system at a receiving end is obtained, (6) the displacement mapping iteration is decoded to obtain a decryption frame corresponding to the plaintext frame, and then spatiotemporal chaos secret communication is achieved. According to the spatiotemporal chaos secret communication method, signals are coded and decoded by means of spatiotemporal chaos, the spatial state values of the one-way coupling image lattice system are grouped, iteration and aliasing of a plaintext secret key are carried out, better confidentiality is achieved, the method can be achieved easily by means of a microprocessor, integration can be achieved easily.

Description

A kind of space-time chaos secret communication method

Technical field

The invention belongs to private communication technology field, relate to a kind of space-time chaos secret communication method.

Background technology

The appearance of computer and progressively universally make day by day information-based, society's networking day by day of epoch, information security and the privacy problem ever more important that seems.Chaos due to its to the essential characteristics such as the sensitiveness of initial value, interior randomness, broadband power spectrum make its in anti-interference, intercepting and capturing rate, signal is hidden and the aspect such as confidentiality has potential advantage, becomes the study hotspot in secure communication field.Along with chaotic communication successfully applies to commercial fiber channel, obtained higher transmission rate, the research of chaotic communication is gradually to practical development.Simultaneously, the research of the safety analysis of existing chaos encrypting method and attack technology is also subject to extensive concern, comprises use nonlinear prediction (NLD), return the decoding that the methods such as mapping, short-time zero-crossing rate, analysis of spectrum, generalized synchronization, the identification of self adaptation keying are carried out secure communication.Existing Development of Chaotic Secure Communication Method, security performance can't meet the requirement on utilization.

Summary of the invention

The object of this invention is to provide a kind of space-time chaos secret communication method, the chaos time sequence that shines upon trellis system generation by unidirectional couplings is encrypted cleartext information, secrete key signal and expressly dynamics and the statistical property of signal, increase and decode difficulty, security performance is got a promotion.

The technical solution adopted in the present invention is, a kind of space-time chaos secret communication method, the spatiality of unidirectional couplings being shone upon to trellis system generation is divided into very, occasionally ties up state vector as key sequence, key and plaintext obtain ciphertext signal through N displacement iteration, with this ciphertext signal, drive the unidirectional couplings reflection trellis system of transmitting terminal and receiving terminal to realize synchronously and modulate next state of chaotic system constantly simultaneously; Signal after encryption receives through common signal channel receiving end, and receiving terminal unidirectional couplings reflection trellis system can Complete Synchronization under the driving effect identical with transmitting terminal trellis system; Finally, the state vector after employing is synchronous, as decruption key, through N corresponding displacement iteration map, obtains the plaintext frame of transmission.

The invention has the beneficial effects as follows, utilize space-time chaos to carry out encoding and decoding to signal, unidirectional couplings is shone upon to the spatiality value grouping of trellis system, and carry out clear text key iteration aliasing, realize encryption and decryption, feature comprises: 1) in channel, transmission information does not comprise key and direct information expressly, can resist better the attack of the methods such as phase space reconfiguration, obtains better confidentiality; 2) ciphering process algorithm is relatively simple, is easy to microprocessor realization and integrated.

Accompanying drawing explanation

Fig. 1 is space-time chaos secret communication method theory diagram of the present invention;

Fig. 2 is the space-time chaos state diagram of the unidirectional couplings mapping trellis system in the inventive method;

Fig. 3 is that two unidirectional couplings in the inventive method are shone upon the trellis system state change map of the lower corresponding grid of sequence driving at one time;

Fig. 4 is that two unidirectional couplings in Fig. 3 are shone upon the trellis system error change figure of the lower corresponding the same space state of sequence driving at one time;

Fig. 5 is the displacement nonlinear mapping plot in the inventive method;

Fig. 6 is the sinusoidal signal transmitted signal in the inventive method;

Fig. 7 is the signal transmitting in the channel while sending signal in Fig. 6;

Fig. 8 is the decrypted signal of corresponding diagram 6 transmitted signals in the inventive method;

Fig. 9 is the primary signal in the synchronous transient process in the inventive method;

Figure 10 is the decrypted signal in the synchronous transient process in Fig. 9;

Figure 11 is while comprising noise in channel, the decrypted signal waveform that Fig. 6 transmitted signal is corresponding;

Figure 12 is the voice signal sending in the inventive method;

Figure 13 is the noisy ciphertext signal of tool transmitting in channel while sending Figure 12 signal;

Figure 14 is the decrypted signal of Figure 13;

Figure 15 is the waveform enlarged drawing that the voice primary signal when channel contains noise in the inventive method is conciliate cipher tone signal;

Figure 16 is the DSP experiment block diagram in the inventive method;

Figure 17 is the ciphertext signal in the DSP speech secure communication experiment in the inventive method;

Figure 18 is the primary signal in the DSP speech secure communication experiment in Figure 17;

Figure 19 is the decrypted signal in the DSP speech secure communication experiment in Figure 18.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Space-time chaos secret communication method overall work process of the present invention is, the spatiality of unidirectional couplings being shone upon to trellis system generation is divided into very, occasionally ties up state vector as key sequence, key and plaintext obtain ciphertext signal through N displacement iteration, with this ciphertext signal, drive the unidirectional couplings reflection trellis system of transmitting terminal and receiving terminal to realize synchronously and modulate next state of chaotic system constantly simultaneously; Signal after encryption receives through common signal channel receiving end, and receiving terminal unidirectional couplings reflection trellis system can Complete Synchronization under the driving effect identical with transmitting terminal trellis system; Finally, the state vector after employing is synchronous, as decruption key, through N corresponding displacement iteration map, obtains the plaintext frame sending.

As Fig. 1, the model construction that space-time chaos secret communication method of the present invention relies on is, signal transmitting terminal and signal receiving end unidirectional couplings reflection trellis system are respectively provided with a m dimension coupled oscillator, be designated as respectively OCOML-L and OCOML-R, unidirectional couplings reflection trellis system (1) is under the effect of drive sequences, obtain space-time chaos, each is t constantly, completes a plaintext frame $p_t=[p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,p\left(\frac{m(t+1)}{2}\right)]$ Middle m/2 encryption expressly, obtains ciphertext frame $v_{\mathrm{Rt}}=[v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,v_R\left(\frac{m(t+1)}{2}\right)],$ The driving signal that calculates transmitting terminal unidirectional couplings reflection next moment of trellis system is $x_{t+1}\left(0\right)=V_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{v}_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)$ Be used for driving transmitting terminal unidirectional couplings reflection trellis system, the ciphertext frame receiving after transmission is

calculate

during as next, the drive receiving terminal unidirectional couplings of etching system reflection trellis system realizes synchronously, and the grid state after utilizing synchronously decrypts transmitted signal through the process contrary with transmitting terminal

Space-time chaos secret communication method of the present invention, utilizes above-mentioned model, according to following steps, specifically implements:

Step 1, the space lattice state of transmitting terminal unidirectional couplings reflection trellis system is divided into odd number peacekeeping Even-dimensional

The expression formula of encrypting end m dimension (establishing m is even number) unidirectional couplings mapping trellis system OCOML-L is suc as formula (1):

x ₀(i)＝init(i)

x _t(0)＝d(t)

x _t+1(i)＝(1-ε _i)f[x _t(i)]+ε _if[x _t(i-1)]’ (1)

i＝1,2...,m

By t (t >=0) constantly m the spatiality of OCOML-L be divided into two groups of odd number peacekeeping Even-dimensionals, the every group of vector that is length m/2, is expressed as:

Odd number dimension state vector: v _2t=[ax _t(1), ax _t(3) ..., ax _t(m-1)],

Even-dimensional state vector: v _1t=[ax _t(2), ax _t(4) ..., ax _t(m)],

Wherein, x _t(i) be i locus of transmitting terminal at t state constantly, gain a is a constant that is less than 1,

Utilize formula (1) to produce space-time chaos, f in the embodiment of the present invention (x) is taken as Logistic mapping, that is: f (x)=4x (1-x), stiffness of coupling ε _i=0.85 (i=1,2 ..., m); Choose unidirectional couplings oscillator quantity m=10, its initial value init _l=[0.3,0.6,0.2,0.9,0.6,0.8,0.1,0.3,0.4,0.2], as drive sequences x _t(0) for being chosen as while obeying equally distributed random sequence, obtain the space-time chaos state diagram (see figure 2) of unidirectional couplings reflection trellis system, the coordinate i in Fig. 2 is space dimensionality, and t is discrete time, x _t(i) be state amplitude.

If transmitting terminal OCOML-L model is formula (2):

x _t+1(i)＝(1-ε _i)f[x _t(i)]+ε _if[x _t(i-1)] (2)

Receiving terminal OCOML-R model is formula (3):

y _t+1(i)＝(1-ε _i)f[y _t(i)]+ε _if[y _t(i-1)] (3)

In parameter in above-mentioned OCOML-L and OCOML-R, the definition of parameter is in full accord;

As stiffness of coupling ε _i=0.85 (i=1,2 ..., in the time of m), two systems are at identical 0 bit time sequence (x _t(0)=y _t(0) under driving), can reach synchronous, in order to prove this point, it is init that above-described embodiment is established transmitting terminal unidirectional couplings oscillator initial value _l=[0.3,0.6,0.2,0.9,0.6,0.8,0.1,0.3,0.4,0.2], establish receiving terminal unidirectional couplings oscillator initial value is init simultaneously _r=[0.1,0.4,0.8,0.6,0.3,0.9,0.2,0.7,0.5,0.8], obeys equally distributed random sequence if drive sequences is chosen as, and can realize the synchronous of two unidirectional couplings mapping trellis system.

Fig. 3 is the tenth spatiality temporal evolution figure of two unidirectional couplings mapping trellis system, and Fig. 4 is the synchronous error of these two corresponding spatialities.From Fig. 3 and Fig. 4, can find out, under the effect of identical drive sequences, can Complete Synchronization through the corresponding spatiality of very short time latter two systems.

Suppose to be engraved under the driving of identical drive sequences 0 to t-1 time, transmitting terminal is realized and being synchronizeed with receiving terminal unidirectional couplings reflection trellis system, by t (t >=0) constantly m the spatiality of OCOML-L be divided into two groups of odd number peacekeeping Even-dimensionals, the every group of vector that is length m/2, is expressed as:

Odd number dimension state vector: v _2t=[ax _t(1), ax _t(3) ..., ax _t(m-1)]

Even-dimensional state vector: v _1t=[ax _t(2), ax _t(4) ..., ax _t(m)]

Wherein, x _t(i) be i locus of transmitting terminal at t state constantly, gain a is a constant that is less than 1;

In above-described embodiment, establish a=0.4, the vector that t encrypts the individual spatiality formation of end m (m=10) is constantly x _t=[0,0.858,0.912,0.598,0.45,0.912,0.598,0.432,0.858,0.912], odd number peacekeeping Even-dimensional is respectively: odd number dimension state vector: v _2t=[0,0.3648,0.18,0.2392,0.3432],

Even-dimensional state vector: v _1t=[0.3432,0.2392,0.3648,0.1728,0.3648];

Step 2, plaintext frame and odd number dimension state vector is carried out to the iteration of maps that is shifted for N time

Take out successively m/2 expressly as t plaintext frame constantly to be encrypted, expression formula is:

$p_t=[p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,p\left(\frac{m(t+1)}{2}\right)],$ Subscript t is consistent with the discrete time of unidirectional couplings mapping trellis system,

M/2 element in plaintext frame tieed up to corresponding being done as follows in state vector with t moment odd number:

E(p _t, v _2t), wherein, every couple of element computing function e (z ₁, z ₂) suc as formula (4):

F ₁(z ₁, z ₂) be following nonlinear function formula (5):

$f_1(z_1,z_2)=\left\{\begin{array}{cc}(z_1+z_2)+2h,& -2h\&le;(z_1+z_2)\&le;-h\\ (z_1+z_2),& -h<(z_1+z_2)<h\\ (z_1+z_2)-2h,& h\&le;(z_1+z_2)\&le;2h\end{array}\right.---\left(5\right)$

As shown in Figure 5, the mapping that is shifted, e (z ₁, z ₂) be N iterative cryptographic function f ₁, N is any positive integer, selects suitable threshold value h to make z ₁and z ₂codomain scope in (h, h), have:

$\left\{\begin{array}{cc}{z}_i>h& z_i=h\\ z_i<-h& z_i=-h\end{array}\right.i=\mathrm{1,2}---\left(6\right)$

For above-described embodiment, first suppose that transmitted signal is the sinusoidal signal of 0.2 cycles 2 of amplitude π, the sampling period is 100Hz, expressly signal is:

P=[0,0.0126,0.0251,0.0375,0.0497,0.0618,0.0736,0.0852,0.0964,0.1072 ..., 0.2,0.1996 ...] take out successively m/2 and expressly form expressly frame $p_t=[p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),p(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,p\left(\frac{m(t+1)}{2}\right)],$ Suppose that t plaintext frame is constantly p _t=[0,0.0126,0.0251,0.0375,0.0497], by the plaintext frame with m/2 element and t, m/2 element is corresponding in odd number dimension state vector constantly according to formula (4), operates, and gets h=0.7, and N=30, obtains e (p _t, v _2t)=[0 ,-0.2434 ,-0.1749,0.2135,0.545];

Step 3, acquisition signal transmission

The ciphertext frame transmitting in channel is:

$v_{\mathrm{Rt}}=\frac{1}{2}(v_{1t}-e(p_t,v_{2t})+b)---\left(7\right)$

Wherein, the corresponding discrete time of t, b is a constant that is less than 1, the ciphertext frame of transmission comprises m/2 element equally $v_{\mathrm{Rt}}=[v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,v_R\left(\frac{m(t+1)}{2}\right)],$ So far, utilize OCOML-L t m spatiality value constantly completed to a frame (

individual) encryption expressly, formed a ciphertext frame;

For above-described embodiment, by formula (7), get b=0.4, the ciphertext frame that obtains transmission is:

$v_{\mathrm{Rt}}=[v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),v_R(\frac{\text{<figure-callout id="2" label="mt" filenames="HDA0000401864110000011.png,HDA0000401864110000031.png" state="{{state}}">mt</figure-callout>}}{\text{2}}+2),...,v_R\left(\frac{m(t+1)}{2}\right)]=\left[\mathrm{0.3716,0.4413,0.4699,0.1797,0.1095}\right];$

Step 4, calculating transmitting terminal unidirectional couplings mapping trellis system are at t+1 driving signal constantly

Driving signal at t+1 moment OCOML-L is $x_{t+1}\left(0\right)=V_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{v}_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l),$

For above-described embodiment, according to above-mentioned computational methods, the driving signal that constantly sends coupling reflection grid OCOML-L at t+1 is $x_{t+1}\left(0\right)=V_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{v}_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)=0.3144;$

The synchronous signal obtaining of step 5, receiving terminal unidirectional couplings mapping trellis system

Receiving terminal has m dimension unidirectional couplings mapping trellis system OCOML-R equally, and its parameter is identical with OCOML-L, and its system model is suc as formula (3), and the driving signal of OCOML-R is:

$y_{t+1}\left(0\right)={\tilde{V}}_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{\tilde{v}}_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l),$ Wherein ${\tilde{v}}_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)$ For $v_R(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)$ By the reception signal after transmission,

For above-described embodiment, due to two unidirectional couplings reflection trellis system Complete Synchronizations, the individual grid state of m (m=10) of receiving terminal unidirectional couplings Map Lattices system is identical with transmitting terminal grid state, i.e. y _t=[0,0.858,0.912,0.598,0.45,0.912,0.598,0.432,0.858,0.912],

Step 6, deciphering displacement iteration of maps

The spatiality of t moment OCOML-R is also pressed to odd number peacekeeping Even-dimensional separately, obtains state vector:

Odd number dimension state vector is: ${\tilde{v}}_{2t}=[a{y}_t\left(1\right),a{y}_t\left(3\right),...,a{y}_t(m-1)],$

Even-dimensional state vector is:

parameter a in this two formula is identical with step 1,

By the ciphertext frame receiving

do lower rank transformation:

$w_t={\tilde{v}}_{1t}-(2{\tilde{v}}_{\mathrm{Rt}}-b),---\left(8\right)$

Equally to vector $w_t=[w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+1),w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+2),...,w\left(\frac{m(t+1)}{2}\right)]$ A middle m/2 element is with h value amplitude limit:

$\left\{\begin{array}{cc}w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)>h& w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)=h\\ w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)<-h& w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)=-h\end{array}\right.l=\mathrm{1,2},...,\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">m</figure-callout>}}{2},---\left(9\right)$

The plaintext of deciphering is:

F ₁, N, h is identical with the value of transmitting terminal,

For above-described embodiment, can access:

Odd number dimension state vector: ${\tilde{v}}_{2t}=\left[\mathrm{0,0.3648,0.18,0.2392,0.3432}\right],$

Even-dimensional state vector: ${\tilde{v}}_{1t}=\left[\mathrm{0.3432,0.2392,0.3648,0.1728,0.3648}\right],$

By the ciphertext frame receiving do lower rank transformation:

$w_t={\tilde{v}}_{1t}-(2{\tilde{v}}_{\mathrm{Rt}}-b),$

Plaintext frame for above-described embodiment, obtains w _t=[0 ,-0.2434 ,-0.1749,0.2135,0.5457];

Equally to vectorial w _tm/2 element with h value amplitude limit:

$\left\{\begin{array}{cc}w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)>h& w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)=h\\ w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)<-h& w(\frac{\mathrm{<figure-callout\; id="2"\; label="mt"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">mt</figure-callout>}}{2}+l)=-h\end{array}\right.l=\mathrm{1,2},...,\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000401864110000011.png,HDA0000401864110000031.png"\; state="\{\{state\}\}">m</figure-callout>}}{2},$

The plaintext of deciphering is:

For the plaintext frame of above-described embodiment, f ₁, N, h is identical with the value of transmitting terminal, obtains

so just, obtained the plaintext frame p that t sends constantly _tcorresponding deciphering frame

.

By that analogy, along with the evolution of the discrete time t of unidirectional couplings oscillator, above-mentioned encrypting and decrypting process can complete the encrypted transmission of more plaintext frames.

Fig. 6-Fig. 8 is the result figure that the sinusoidal signal of the present embodiment sends, and wherein Fig. 6 is transmitted signal, and Fig. 7 is the signal transmitting in channel, and Fig. 8 is decrypted signal.From Fig. 6-Fig. 8, in visible channel, signal transmission waveform is completely different from original signal waveform, and primary signal and decrypted signal waveform are almost identical.

Fig. 9-Figure 10 is the enlarged drawing in the time period of 0s to 5s for t, and Fig. 9 is primary signal, and Figure 10 is decrypted signal, and visible decrypted signal is identical after synchronous transient process with original signal.When actual secure communication, can wait for after synchronous transient process completes and carry out again useful data transmission.

Consider to contain noise in actual channel, therefore in channel, adding scope is (0.05A, even noise 0.05A) (A is the amplitude of transmission sinusoidal signal), as shown in figure 11, Figure 11 is the decrypted signal waveform that Fig. 6 transmitted signal obtains while there is even noise in channel to result.Can find out, even if still can recover preferably after adding noise expressly.Although noise can produce and disturb the plaintext recovering, restoring signal can the impact to reduce to disturb by simple filtering.

The one section of speech data of take carries out test transmission as example, further verifies the validity of this programme, obtains result with reference to Figure 12-Figure 14, and wherein Figure 12 is the voice signal of transmission, and Figure 13 is the ciphertext signal transmitting in channel, and Figure 14 is corresponding decrypted signal.Interchannel noise is even noise, and its amplitude is signal transmission maximum amplitude 10%.After synchronously completing, send waveform that primary signal and (existing in channel in the situation of above-mentioned noise) obtain decrypted signal as shown in figure 15.As seen from Figure 15, original waveform is basic identical with deciphering waveform overall trend, although add the deciphering waveform after noise to have certain deviation with original waveform, for the almost not impact of auditory effect that decrypts the voice of signal.

Adopt the Floating-point DSP TMS320C6713DSK of TI company to carry out hardware experiments, experimental principle block diagram as shown in figure 16.At transmitting terminal, voice signal is by A/D sampling and the coding of Codec, primary voice data is sent into DSP, in DSP, move cryptographic algorithm of the present invention, signal after encryption is through voice-grade channel transmission, receiving terminal receives after signal transmission, and recycling decipherment algorithm is realized deciphering in DSP, by the D/A recovery voice signal of Codec.Experimental result is as shown in Figure 17-19.Figure 17 is ciphertext signal, the primary signal of Figure 18 for sending, and Figure 19 is decrypted signal.Relatively Figure 18 figure and Figure 19 figure can find out, primary signal and decrypted signal are almost identical, completely different from the ciphertext signal transmitting, and the signal transmitting in channel has been covered cleartext information completely, and sounding is exactly noise.Result has proved that the empty chaos speech security of now the present invention method had both had good confidentiality, can recover original signal again well.

Claims (3)

1. a space-time chaos secret communication method, it is characterized in that, the spatiality of unidirectional couplings being shone upon to trellis system generation is divided into very, occasionally ties up state vector as key sequence, key and plaintext obtain ciphertext signal through N displacement iteration, with this ciphertext signal, drive the unidirectional couplings reflection trellis system of transmitting terminal and receiving terminal to realize synchronously and modulate next state of chaotic system constantly simultaneously; Signal after encryption receives through common signal channel receiving end, and receiving terminal unidirectional couplings reflection trellis system can Complete Synchronization under the driving effect identical with transmitting terminal trellis system; Finally, the state vector after employing is synchronous, as decruption key, through N corresponding displacement iteration map, obtains the plaintext frame sending.

2. space-time chaos secret communication method according to claim 1, is characterized in that, specific implementation process is, first adopts a kind of unidirectional couplings mapping trellis system model, suc as formula (1):

x ₀(i)＝init(i)

x _t(0)＝d(t)

x _t+1(i)＝(1-ε _i)f[x _t(i)]+ε _if[x _t(i-1)]’ (1)

i＝1,2...,m

Wherein, t represents discrete time, and m is the space dimensionality of unidirectional couplings mapping trellis system, and init (i) is space i dimension grid initial value, ε _ifor stiffness of coupling satisfied 0 < ε _i< 1, x _t(0)=d (t) is the drive sequences of position 0 grid, t=0, and 1,2..., f (x) is non-linear chaotic maps operator,

Unidirectional couplings mapping trellis system OCOML-L and the OCOML-R of transmitting terminal and receiving terminal are expressed as:

x _t+1(i)＝(1-ε _i)f[x _t(i)]+ε _if[x _t(i-1)]， (2)

y _t+1(i)＝(1-ε _i)f[y _t(i)]+ε _if[y _t(i-1)]， (3)

The definition of the middle parameter of the parameter in formula (3) and formula (2) is in full accord, as stiffness of coupling ε _iwhen identical, two systems shown in formula (2) and formula (3) are at identical 0 bit time sequence (x _t(0)=y _t(0) driving) is issued to synchronously, and this time series is called drive sequences,

Model structure based on above-mentioned, this space-time chaos secret communication method, according to following steps, implement:

Step 1, the spatiality of transmitting terminal unidirectional couplings mapping trellis system is divided into odd number peacekeeping Even-dimensional

Encrypt end m dimension unidirectional couplings mapping trellis system OCOML-L suc as formula shown in (1), establishing m is even number, by t constantly m the grid state of OCOML-L be divided into two groups of odd number peacekeeping Even-dimensionals, the moment, t was more than or equal to 0, the every group of vector that is length m/2, is expressed as:

Odd number dimension state vector: v _2t=[ax _t(1), ax _t(3) ..., ax _t(m-1)],

Even-dimensional state vector: v _1t=[ax _t(2), ax _t(4) ..., ax _t(m)],

Wherein, x _t(i) be i locus of transmitting terminal at t state constantly, gain a is less than 1 constant;

Step 2, plaintext frame and odd number dimension state vector is carried out to the iteration of maps that is shifted for N time

Take out successively m/2 expressly as t plaintext frame constantly to be encrypted, expression formula is:

$p_t=[p(\frac{\mathrm{mt}}{2}+1),p(\frac{\mathrm{mt}}{2}+2),...,p\left(\frac{m(t+1)}{2}\right)],$ Subscript t is consistent with the discrete time of unidirectional couplings mapping trellis system,

M/2 element in plaintext frame tieed up to corresponding being done as follows in state vector with t moment odd number: e (p _t, v _2t), wherein, every couple of element computing function e (z ₁, z ₂) suc as formula (4):

F ₁(z ₁, z ₂) be following nonlinear function formula (5):

$f_1(z_1,z_2)=\left\{\begin{array}{cc}(z_1+z_2)+2h,& -2h\&le;(z_1+z_2)\&le;-h\\ (z_1+z_2),& -h<(z_1+z_2)<h\\ (z_1+z_2)-2h,& h\&le;(z_1+z_2)\&le;2h\end{array}\right.,---\left(5\right)$

The mapping that is shifted, e (z ₁, z ₂) be N iterative cryptographic function f ₁, N is any positive integer, selects suitable threshold value h to make z ₁and z ₂codomain scope in (h, h), have:

$\left\{\begin{array}{cc}{z}_i>h& z_i=h\\ z_i<-h& z_i=-h\end{array}\right.,i=\mathrm{1,2};---\left(6\right)$

Step 3, acquisition signal transmission

The ciphertext frame transmitting in channel is:

$v_{\mathrm{Rt}}=\frac{1}{2}(v_{1t}-e(p_t,v_{2t})+b),---\left(7\right)$

The corresponding discrete time of t wherein, b is less than 1 constant, and the ciphertext frame of transmission comprises m/2 element equally $v_{\mathrm{Rt}}=[v_R(\frac{\mathrm{mt}}{2}+1),v_R(\frac{\mathrm{mt}}{2}+2),...,v_R\left(\frac{m(t+1)}{2}\right)],$ So far, utilize OCOML-L to complete a frame at t m state value constantly

the encryption of individual plaintext, has formed a ciphertext frame;

Step 4, calculating transmitting terminal unidirectional couplings mapping trellis system are at t+1 driving signal constantly

Driving signal at t+1 moment OCOML-L is:

$x_{t+1}\left(0\right)=V_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{v}_R(\frac{\mathrm{mt}}{2}+l);$

The synchronous signal obtaining of step 5, receiving terminal unidirectional couplings mapping trellis system

Receiving terminal has m dimension unidirectional couplings mapping trellis system OCOML-R equally, and its parameter is identical with OCOML-L, and its system model is suc as formula (3), and the driving signal of OCOML-R is:

$y_{t+1}\left(0\right)={\tilde{V}}_R(t+1)=\frac{1}{(m/2)}\underset{l=1}{\overset{m/2}{\mathrm{\&Sigma;}}}{\tilde{v}}_R(\frac{\mathrm{mt}}{2}+l),$ Wherein ${\tilde{v}}_R(\frac{\mathrm{mt}}{2}+l)$ For $v_R(\frac{\mathrm{mt}}{2}+l)$ By the reception signal after transmission;

Step 6, deciphering displacement iteration of maps

The spatiality of t moment OCOML-R is also separately obtained to state vector by odd number peacekeeping Even-dimensional:

Odd number dimension state vector is: ${\tilde{v}}_{2t}=[a{y}_t\left(1\right),a{y}_t\left(3\right),...,a{y}_t(m-1)],$

Even-dimensional state vector is: ${\tilde{v}}_{1t}=[a{y}_t\left(2\right),a{y}_t\left(4\right),...,a{y}_t\left(m\right)],$ Parameter a in this two formula is identical with step 1;

By the ciphertext frame receiving

do lower rank transformation:

$w_t={\tilde{v}}_{1t}-(2{\tilde{v}}_{\mathrm{Rt}}-b),---\left(8\right)$

Equally to vector $w_t=[w(\frac{\mathrm{mt}}{2}+1),w(\frac{\mathrm{mt}}{2}+2),...,w\left(\frac{m(t+1)}{2}\right)]$ A middle m/2 element is with h value amplitude limit:

$\left\{\begin{array}{cc}w(\frac{\mathrm{mt}}{2}+l)>h& w(\frac{\mathrm{mt}}{2}+l)=h\\ w(\frac{\mathrm{mt}}{2}+l)<-h& w(\frac{\mathrm{mt}}{2}+l)=-h\end{array}\right.l=\mathrm{1,2},...,\frac{m}{2},---\left(9\right)$

The plaintext of deciphering is:

F ₁, N, h is identical with the value of transmitting terminal, has obtained deciphering frame corresponding to plaintext frame that t sends constantly.

3. space-time chaos secret communication method according to claim 2, is characterized in that: in described formula (1), f (x) is taken as Logistic mapping, that is: f (x)=4x (1-x), stiffness of coupling ε _i=0.85, i=1,2 ..., m.

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