CN105761198A - Image selective encryption and decryption method based on dynamic probability and space-frequency domain compositing - Google Patents

Abstract

The invention provides an image selective encryption and decryption method based on dynamic probability and space-frequency domain compositing. The MD5 value and SHA-1 value of a to-be-encrypted image are composited to improve the impact resistance of a single Hash feature, and intermediate key parameters are generated through close coupling to a user key to carry out probability interval division, probability generation and to-be-encrypted pixel screening and to determine a probabilistic encryption event and transform parameters. The designed encryption event includes a space domain and frequency domain replacement operation to improve the efficiency of encryption and avoid the influence of frequency domain coefficient overflow on the recovery of the visual quality of the image. According to the method, the encryption features of the to-be-encrypted image and the user key are updated, so that the key parameters under the condition of different number of encryption times differ greatly and are closely associated with the features of the to-be-encrypted image and the user key, and image visual quality and frequency domain overflow filtering control can be carried out through a preset encryption threshold. For decryption, an intermediate key set needs to be restored first, and then, the screened pixel blocks are decrypted reversely.

Description

Image selective encryption that a kind of dynamic probability and null tone territory are compound and decryption method

Technical field

The invention belongs to information security and data image signal processes crossing research field, relate to a kind of image encryption and conciliate Decryption method, the image selective encryption compound particularly to a kind of dynamic probability and null tone territory and decryption method.

Background technology

Be generally directed to is entire image in traditional images encryption, changed beyond recognition with secret for entire image being converted to Figure, not only brings high calculation cost, also masks the image to be encrypted all features almost in addition to size.A lot In actual application, often it is not required to entire image is encrypted, and only needs bit plane, region and the part picture selected to image Element is encrypted, and needs the Partial Feature providing original image to come to potential user with more experience while encryption, Thus exchange bigger commercial interest for, and the characteristics of image that these encrypted images are retained, can be further used for image classification, Retrieval and identification etc., thus encrypt relative to traditional images, possess more use value.This only to the bit that image is selected Plane, region and the method for partial pixel encryption, be referred to as selective encryption.

Encrypt for selective image, mainly have than more typical selective image encryption method at present:

1. partial bit plane or bit to choosing carry out selective encryption.Such as, Rehman A U, 2015. (Rehman A U,Liao X,Kulsoom A,et al.Selective encryption for gray images based on chaos and DNA complementary rules[J].Multimedia Tools and Applications, 2015,74 (13): 4655-4677) the high-low-position bit plane treating encrypted image is encrypted by different DNA sequence dnas. Kulsoom A,2016.(Kulsoom A,Xiao D,Aqeel-ur-Rehman,et al.An efficient and noise resistive selective image encryption scheme for gray images based on chaotic maps and DNA complementary rules[J].Multimedia Tools and Applications,2016,75 (1) the MD5 value of image: 1-23.) it is further introduced into improve Rehman A U, the anti-chosen-plain attact of strategy described in 2015 Ability.Moon D,2006.(Moon D,Chung Y,Pan S B,et al.An efficient selective encryption of fingerprint images for embedded processors[J].ETRI journal, 2006,28 (4): 444-452.) LSB of pixel carries out XOR encryption as random keystream and high order bit position cover and treat Encrypted image feature, and the security of described strategy is improved by secrecy LSB.Vanogenbroeck M,2002. (Vanogenbroeck M,Benedett R.Techniques for a selective encryption of uncompressed and compressed images[C]//in Proceedings of Advanced Concepts For Intelligent Vision Systems (ACIVS) 2002.2002:90-97.) utilize 2 values big with close figure etc. random The bit plane that double secret key is selected carries out XOR encryption by turn.Zhong Ming, 2008. (Zhong Ming, Liao Xiaofeng, Zhou Qing. a kind of based on four forks Spatial domain picture Choice encryption algorithm [J] of tree. computer engineering, 2008,34 (18): 174-178.) by bit selected for image Plane is divided into 8 × 8 fritters, is set the position decomposing node with layer by the position relationship and exchange 8 × 8 fritter 4 fork changing fritter Put order selected bit plane is encrypted.Xiang T,2007.(Xiang T,Wong K,Liao X.Selective image encryption using a spatiotemporal chaotic system[J].Chaos: An Interdisciplinary Journal of Nonlinear Science, 2007,17 (2): 415-427.) use base Tie up coupled map lattices in the 1 of skew tent map and the bit plane chosen is carried out selective encryption, and to be encrypted by adjusting Notable bit plane quantity compromise in security and encryption performance.Hoang T,2014.(Hoang T,Tran, D.Cryptanalysis and security improvement for selective image encryption[J] .European Physical Journal Special Topics, 2014,223 (8): 1635-1646.) to Xiang T, The security of 2007 is analyzed, and the notable number of bits participating in encryption by changing each pixel improves described strategy Security.Rehman A U, 2015, Kulsoom A, 2016, Moon D, 2006, Vanogenbroeck M, 2002, Zhong Ming, 2008, Xiang T, 2007 and Hoang T, 2014 are all based on the selective image encryption of bit plane or bit.Different Be Rehman A U, 2015 and Kulsoom A, 2016 pairs of high-low-position bit planes have employed different encryption policys；Moon D, 2006 is as the key encrypting high order bit plane XOR using low-order bit plane；Vanogenbroeck M, 2002, Zhong Ming, 2008 and Xiang T, 2007 are to be encrypted the bit plane chosen；Hoang T, different pixels is entered by 2014 The bit encryption of row varying number.The ratio that selective encryption strategy based on bit plane and bit can be encrypted by adjustment The quantity of special plane and encrypting bit position adjusts the visual quality of image to be encrypted, if encryption amount is too much, then tends to tradition Image encryption, if being only encrypted notable position or notable plane, then loses the identification feature of image, if only to not notable bit Plane is encrypted, then cannot be effectively reduced the visual quality of image.If using LSB as key, then it is prone to brokenly in transmitting procedure Bad, cause encrypted image to recover.For gray scale or coloured image, the most limited alternative bit plane, pass through Select different bit planes that the visual quality of image encryption cost and encrypted image is regulated and controled, the regulation and control that can play Act on extremely limited.

2. image pixel and block of pixels are screened, the pixel filtered out and block of pixels are carried out selective encryption.Example As, Zhao Liang, 2010. (Zhao Liang, Liao Xiaofeng, Xiang Tao etc. map based on Z matrix and the coloured image degeneration algorithm of Choice encryption grinds Study carefully. Acta Physica Sinica [J], 2010,59 [3]: 1507-1523.) give based on pixel random screening masterplate and Pixel Information entropy Image degradation encryption method.Lin Yangfei, 2015. (Lin Yangfei, Ye Shaozhen. a kind of selective encryption method of medical image data. Application of electronic technology [J], 2015,41 (3): 107-110.) utilize the pixel of image block and the block of pixels of encryption is carried out Screening, is encrypted the block of pixels filtered out by SCAN language and image hash value.Wen W,2015.(Wen W,Zhang Y,Fang Z,et al.Infrared target-based selective encryption bychaotic maps[J] .Optics Communications, 2015,341:131 139.) utilize geometric active contour and partial differential equation to infrared figure The target area of picture is screened, and is then encrypted the block of pixels filtered out.Khashan O A,2014.(Khashan O A,Zin A M,Sundararajan E A.Performance study of selective encryption in comparison to full encryption for still visual images[J].Journal of Zhejiang University SCIENCE C, 2014,15 (6): 435-444.) the not overlap partition that image is divided calculate pixel and, root The block of pixels that blowfish encrypts is filtered out according to pixel and the relation set between threshold value.Zhang T,2013.(Zhang T, El-Latif A,Han Q,et al.Selective Encryption for Cartoon Images[C]// Intelligent Human-Machine Systems and Cybernetics(IHMSC),20135th International Conference on.IEEE, 2013,2:198-201.) utilize scalable Shape context to screen card release Important information block to be encrypted in logical image.Ayoup A M,2015.(Ayoup A M,Hussein A H,Attia M A A.Efficient selective image encryption[J].Multimedia Tools and Applications, 2015:1-16.) the comentropy largest block filtered out is carried out AES encryption.Mehta G,2014.(Mehta G,Dutta M K, Travieso-Gonzalez C M,et al.Edge based selective encryption scheme for biometric data using chaotic theory[C]//Contemporary Computing and Informatics (IC3I), 2014International Conference on.IEEE, 2014:383-386.) only opposite side The notable block that edge detection filters out is encrypted, and is made a distinction notable block and non-significant block by encryption vector.Zhao Liang, 2010, Wen W, 2015, Khashan O A, 2014, Mehta G, 2014, Zhang T, 2013, Ayoup A M, 2015 Hes Mehta G, 2014 is all that the pixel filtered out on image and block of pixels are carried out selective encryption, need to set screening when screening Threshold value filters out pixel and the block of pixels of correspondence, owing to before and after encryption, block of pixels is the most corresponding, for keeping encryption policy Restorability, typically need to ensure encryption screening feature do not change or by record and embed encryption parameter come to encryption and not Pixel and the block of pixels of encryption make a distinction.For the former, generally it is only capable of selecting fixing encrypted feature, such as comentropy or only Simple encryption policy can be used to ensure that encrypted feature does not changes；For the latter, store extra encryption parameter usual Need higher storage cost.

3. the sensitizing range selected user carries out selective encryption.Ravishankar K C,2006. (Ravishankar K C,Venkateshmurthy M G.Region based selective image encryption [C]//Computing & Informatics,2006.ICOCI'06.International Conference on.ieee, 2006:1-6.) sensitizing range that user selectes is divided into nonoverlapping fritter, the fritter comprising sensitizing range is selected Property encryption.Ou Y,2007.(Ou Y,Sur C,Rhee K H.Region-based selective encryption for medical imaging[M]//Frontiers in Algorithmics.Springer Berlin Heidelberg, 2007:62-73.) specify sensitizing range to carry out AES deciphering user.Ravishankar K C, 2006 and Ou Y, 2007 are all The area-of-interest selecting user carries out selective encryption, when deciphering, need to provide the most selected sensitizing range, the most also Bring extra storage cost.

4. frequency coefficient specific to image carries out selective encryption.Wang Lihua, 2010. (Wang Lihua, Liao Xiaofeng, Xiang Tao Manually degenerate algorithm [J] Deng. image based on wavelet transformation. computer engineering, 2010,36 (16): 203-207.) by original graph As being converted to the wavelet field subgraph of different frequency composition, by HFS interpolation multiplicative noise and additive noise are come figure As carrying out frequency domain selective encryption.Nidhi Taneja,2011.(Nidhi Taneja,Balasubramanian Raman, Indra Gupta.Selective image encryption in fractionalwavelet domain[J].AEU- International Journal of Electronics and Communications,2011,65(4):338-344.) In Fourier Transform of Fractional Order territory, energy component is carried out the displacement of Arnold position and XOR encryption more than the sub-band of threshold value. Wang Lihua, 2010 and Nidhi Taneja, 2011 are to change image to frequency domain, select specific frequency coefficient to add Close, at frequency domain, choose the different frequency coefficient of significance level and can effectively regulate and control visual quality of images, but simultaneously to frequency coefficient Encryption also can change the amplitude area of frequency coefficient, thus causes spatial domain pixel overflow and cannot correctly decipher.

In addition to the above problems, selective image encryption there is also the safety problem existing for traditional images encryption, example Such as displacement and the loose coupling of process of obfuscation, the problems such as concrete encryption policy is unrelated with image to be encrypted.

Summary of the invention

Present invention aim to overcome that prior art defect, it is provided that the image that a kind of dynamic probability and null tone territory are combined selects Property encryption and decryption approaches, designed encrypted event include spatial domain and frequency domain replacement operator with improve encryption efficiency and avoid frequency Domain coefficient overflows the impact recovering visual quality of images, simultaneously can be by encryption threshold value set in advance to visual quality of images It is controlled.

For achieving the above object, the present invention is by the following technical solutions:

The image selective cryptographic method that a kind of dynamic probability and null tone territory are combined, comprises the following steps:

1st step: remember that image to be encrypted is A=(a_i,j)_m×nAnd a_i,j∈ 0,1 ..., and 255}, encryption number of times t, t ＞ 0 are set, Primary iteration controls parameter k=1, selected initial parameter μ₀∈ [3.57,4] and setting encryption judgment threshold δ, δ ＞ 0, note A's MD5 value and SHA-1 value are respectively 16 system Number Sequence S_MD5=< m₀,m₁,…,m₃₁> and S_SHA-1=< s₀,s₁,…,s₃₉>, by S_MD5 And S_SHA-1Series connection is 16 system Number Sequence S_ms=S_MD5||S_SHA-1=< sm_i>₇₂And initialization encryption event subscript index sequence S_id For S_id=<0,1 ..., 5>, wherein " | | " it is bit bit string serial operation symbol；

2nd step: by S_msIt is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>；

3rd step: by S_hIt is divided intoFour parts, then willI=0,1 ..., 3 are converted to (0,1) In the range of 10 system decimal G_i, i=0,1 ..., 3；

4th step: by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁, G′₂, by G '₀,G′₁,G′₂As key parameter X_init,Y_init,x_init, i.e. X_init=G '₀,Y_init=G '₁,x_init=G '₂；

5th step: by initial parameter μ₀As systematic parameter, key parameter x_init5 (0,1) scopes are produced as initial value Interior random number is as sequence S_p=< p₀,p₁,p₂,p₃,p₄>, by S_pInterval division sequence S ' in the range of structure (0,1)_p=< p′₀,p′₁,p′₂,p′₃,p′₄>, thus obtain probability interval [0, p '₀),[p′₀,p′₁),[p′₁,p′₂),[p′₂,p′₃),[p′₃, p′₄),[p′₄,1]；

6th step: by key parameter Y_init,μ₀It is mapped as μ₁∈ [3.57,4], by X_initAnd μ₁Respectively as initial value be System parameter iteration produces intermediate key parameter Z in the range of (0,1)_init；

7th step: by X_init,Y_init,Z_initAs initial value, iteration produces 3 real-valued random numbers for 1 time successively as parameter X₀,Y₀,Z₀；

8th step: by X₀,Y₀It is mapped as encrypted image A=(a_i,j)_m×nOn random point (r₀,v₀)；

9th step: by (r₀,v₀) as starting point, from image A=(a to be encrypted_i,j)_m×nFilter out M_in=(m_u,w)_4×4, calculate M_inMapping value Map (M_in), if Map is (M_in) >=δ then performs the 10th step, otherwise by x_initAs probabilistic determination value P, by X₀,Y₀, Z₀Mapping value as transformation parameter v, the probability interval fallen into according to P, perform corresponding spatial domain and frequency domain displacement encryption behaviour Make, then to the matrix fritter M after encryption_outCalculate mapping value Map (M_out)；If Map is (M_out) < δ, then by M_outIn pixel depend on Secondary as image A=(a to be encrypted_i,j)_m×nThe pixel of correspondence position, otherwise by M_inMiddle pixel is directly as image A=to be encrypted (a_i,j)_m×nCorrespondence position pixel；

10th step: utilize X₀,Y₀,Z₀To case index sequence S_idCarry out resetting and update；

11st step: utilize X₀,Y₀,Z₀To initial parameter μ₀And S_ms=< ms_i>₇₂In element be updated operation；

12nd step: if during k≤t, updates k=k+1, repeatedly performs the 2nd step～the 11st step；

13rd step: by A=(a_i,j)_m×nOutput is as encrypted image.

Further, the 2nd step is by S_msIt is mapped as S_h=< h₀,h₁,…,h₃₉> concrete grammar be formula (1):

S_h=Draw (S_ms,start,gap,|S_h|) (1)

In formula (1), Draw () is that sequential element extracts function, and wherein start is extraction starting point, and gap is the sample skipped Number, | S_h| for S_hMiddle number of elements, i.e. from S_msCirculation extraction | S_h| individual 16 system numbers are as S_h, start, gap are respectively by formula (2) Map with formula (3) and obtain:

$start=\left(\underset{i=0}{\overset{31}{\&Sigma;}}\underset{j=0}{\overset{8}{\&Sigma;}}\right(m_i+s_{i+j}\left)\right)\mathrm{mod}\left|S_{ms}\right|---\left(2\right)$

$gap=\left(\underset{i=0}{\overset{31}{\&Sigma;}}\underset{j=0}{\overset{8}{\&Sigma;}}{m}_i{s}_{i+j}\right)\mathrm{mod}\left|S_{ms}\right|---\left(3\right);$

3rd step is by S_hIt is divided intoTetrameric concrete grammar is formula (4):

$S_{h_i}=<h_i,h_{i+1},...,h_{i+9}>,i=0,1,...,3---\left(4\right);$

3rd step willI=0,1 ..., 3 are converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., the tool of 3 Body method is formula (5), and in formula (5), [] is round function:

$G_i=\underset{j=0}{\overset{9}{\&Sigma;}}\&lsqb;10h_{9i+j}/17\&rsqb;\&times;{10}^{-j-1},i=0,1,...,3---\left(5\right).$

Further, the 4th step is by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimals in the range of (0,1) G′₀,G′₁,G′₂Concrete grammar be by G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) iteration and produce 31 time Individual sequential value G '₀,G′₁,G′₂；

$x_{i+1}=\left\{\begin{array}{c}\frac{x_i}{\mathrm{\&alpha;}},0\&le;x_i<\mathrm{\&alpha;}\\ \frac{1-x_i}{1-\mathrm{\&alpha;}},\mathrm{\&alpha;}\&le;x_i<1\end{array}\right.---\left(6\right);$

5th step is by μ₀As systematic parameter, x_initThe random number in the range of 5 (0,1) is produced as sequence as initial value S_p=< p₀,p₁,p₂,p₃,p₄> concrete grammar be by μ₀As systematic parameter, x_initFormula (7) iteration is brought into 5 times as initial value 5 random numbers produced are as sequence S_p=< p₀,p₁,p₂,p₃,p₄>

x_i+1=μ x_i(1-x_i) (7)；

By S in 5th step_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀,p′₁,p′₂,p′₃,p′₄> tool Body method is by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p′₁,p′₂,p′₃,p′₄>。

Further, the 6th step is by Y_init,μ₀It is mapped as μ₁The concrete grammar of ∈ [3.57,4] is formula (8):

${\mathrm{\&mu;}}_1=\sqrt{(0.43\&times;Y_{init}+3.57)\&CenterDot;{\mathrm{\&mu;}}_0}---\left(8\right);$

6th step is by X_initAnd μ₁The intermediate key ginseng in the range of (0,1) is produced respectively as initial value and systematic parameter iteration Number Z_initConcrete grammar be by X_initAnd μ₁Make for 1 time by formula (7) iteration respectively as the initial value in formula (7) and systematic parameter For intermediate key parameter Z_init；

x_i+1=μ x_i(1-x_i) (7)；

7th step is by X_init,Y_init,Z_initAs initial value, iteration produces 3 random numbers for 1 time successively as parameter X₀,Y₀, Z₀Concrete grammar be by X_init,Y_init,Z_initAs the initial value of formula (9), produce 3 random numbers successively iterative (9) 1 times As parameter X₀,Y₀,Z₀, formula (9) systematic parameter takes a=b=0.2, c=5.7；

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{X}}_{i+1}=-Y_i-Z_i\\ {\stackrel{\&CenterDot;}{Y}}_{i+1}=X_i+{\mathrm{aY}}_i\\ {\stackrel{\&CenterDot;}{Z}}_{i+1}=b+Z_i(X_i-c)\end{array}\right.---\left(9\right).$

Further, the 8th step is by X₀,Y₀Being mapped as encrypted image is A=(a_i,j)_m×nOn random point (r₀,v₀) concrete side Method is formula (10), in formula (10)Accord with for downward rounding operation；

9th step is by (r₀,v₀) as starting point, from image A=(a to be encrypted_i,j)_m×nFilter out the matrix fritter M of 4 × 4_in= (m_u,w)_4×4Concrete grammar be formula (11):

$m_{u,w}=a_{r_0+u,v_0+w},u,w=0,1,...,3---\left(11\right);$

9th step calculates M_inMapping value Map (M_in) concrete grammar be by formula (12) calculate M_inVariance:

$Map\left(M_{in}\right)=\frac{1}{16}\underset{u=0}{\overset{3}{\&Sigma;}}\underset{v=0}{\overset{3}{\&Sigma;}}{(m_{u,v}-\frac{1}{16}\underset{u=0}{\overset{3}{\&Sigma;}}\underset{v=0}{\overset{3}{\&Sigma;}}{m}_{u,v})}^2---\left(12\right);$

9th step is to the matrix fritter M after encryption_outCalculate mapping value Map (M_out) concrete grammar be same by formula (12) Method calculate M_outVariance；

By X in 9th step₀,Y₀,Z₀Mapping value be formula (13) as the concrete grammar of transformation parameter v:

9th step performs the spatial domain of correspondence and the concrete grammar of frequency domain displacement cryptographic operation is formula (14):

M_out=Encrypt (M_in,v,P,f,S_id,S′_p) (14)

In formula (14), f={f₀,f₁,…,f₅It is encrypted event set, S_idIt is the subscript index sequence of f, S '_pFor interval Dividing sequence, corresponding 6 group encryption event, the wherein f of encrypted event set f₀,f₁,f₂Spatial domain displacement box encrypted event, such as formula (15) Shown in, f₃,f₄,f₅Transform domain displacement box encrypted event, as shown in formula (16), f₀,f₁,…,f₅Corresponding displacement box Px₀, Px₁,…,Px₅As shown in formula (17)；

$f_i:|M_{out}={\mathrm{Permute}}_0(M_{in},M_{\mathrm{co}de},{\mathrm{Px}}_i,v),i=0,1,2;M_{code}=\left[\begin{array}{cccc}0& 1& 2& 3\\ 4& 5& 6& 7\\ 8& 9& 10& 11\\ 12& 13& 14& 15\end{array}\right]---\left(15\right)$

In formula (15), M_codeIt is M_inNumbering matrix, remember M_inIn element m_u,wAt M_codeIn numbered id, then Permute₀The function that () function performs is by m_u,wMove to Px_iMiddle element value is the coordinate position of (id+v) mod16；

$f_i:\left|\begin{array}{c}{M}_{temp}=M_H{M}_{in}{M}_H\\ M_{temp}={\mathrm{Permute}}_1(M_{temp},M_{code},{\mathrm{Px}}_i,v)\\ M_{out}=\frac{1}{16}{M}_H{M}_{temp}{M}_H\end{array}\right.,i=3,4,5;M_H=\left[\begin{array}{cccc}1& 1& 1& 1\\ 1& -1& 1& -1\\ 1& 1& -1& -1\\ 1& -1& -1& 1\end{array}\right]---\left(16\right)$

In formula (16), M_HIt is Hadamard transform battle array, remembers M_tempIn element mt_u,wAt M_codeIn numbered id and id ≠ ×, Permute₁The operation that () performs is by mt_u,wMove to Px_iMiddle element value is the coordinate position of (id+v) mod16+1, with Permute₀The difference of () is Permute₁() in conversion process, M_tempIn the element of (0,0) position, i.e. id=× element Remaining at (0,0) position does not occur position to change；

$\begin{array}{c}{\mathrm{Px}}_0=\left[\begin{array}{cccc}15& 14& 13& 12\\ 4& 3& 2& 11\\ 5& 0& 1& 10\\ 6& 7& 8& 9\end{array}\right],{\mathrm{Px}}_1=\left[\begin{array}{cccc}0& 7& 8& 15\\ 1& 6& 9& 14\\ 2& 5& 10& 13\\ 3& 4& 11& 12\end{array}\right],{\mathrm{Px}}_2=\left[\begin{array}{cccc}0& 1& 4& 9\\ 3& 2& 5& 10\\ 8& 7& 6& 11\\ 15& 14& 13& 12\end{array}\right],\\ {\mathrm{Px}}_3=\left[\begin{array}{cccc}\&times;& 2& 8& 10\\ 3& 1& 11& 9\\ 12& 14& 4& 6\\ 15& 13& 7& 5\end{array}\right],{\mathrm{Px}}_4=\left[\begin{array}{cccc}\&times;& 1& 4& 5\\ 3& 2& 7& 6\\ 12& 13& 8& 9\\ 15& 14& 11& 10\end{array}\right],{\mathrm{Px}}_5=\left[\begin{array}{cccc}\&times;& 1& 3& 5\\ 2& 7& 8& 10\\ 4& 9& 12& 13\\ 6& 11& 14& 15\end{array}\right]\end{array}---\left(17\right).$

Further, the 10th step utilizes X₀,Y₀,Z₀To case index sequence S_idCarry out resetting the concrete grammar updated for by X₀, Y₀,Z₀Being mapped as start, gap by formula (18) and formula (19), right back-pushed-type (20) is to case index sequence S_idIt is updated:

S_id=Draw (S_id,start,gap,|S_id|) (20)；

11st step utilizes X₀,Y₀,Z₀To initial parameter μ₀The concrete grammar updated is formula (22):

${\mathrm{\&mu;}}_0=0.43(\sqrt{X_0{Y}_0}+\sqrt{Z_0{Y}_0}+\sqrt{X_0{Z}_0})\mathrm{mod}1)+3.57---\left(22\right);$

To S in 11st step_ms=< ms_i>₇₂In element be updated operation method particularly includes: first use X₀,Y₀,Z₀By formula (21) x is generated_init, then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂In element be updated operation；

x_init=(X₀+X₀Y₀+X₀Y₀Z₀)mod1 (21)

x_i+1=μ x_i(1-x_i) (7)

The image selectivity decryption method that a kind of dynamic probability and null tone territory are combined, comprises the following steps:

1st step: inputted key μ by user₀∈[3.57,4],S_MD5,S_SHA-1, encrypt number of times t, t ＞ 0 and encrypted image C, Primary iteration controls parameter k=0, and input encryption judgment threshold δ, δ ＞ 0, by S_MD5And S_SHA-1Series connection is 16 system Number Sequence S_ms =S_MD5||S_SHA-1=< sm_i>₇₂And initialization encryption event subscript index sequence S_id=<0,1 ..., 5>and intermediate key parameter Sequence S_{X ＞},S_{Y ＞},S_{Z ＞},S_{X ＞},S′_{P ＞},S_{Id ＞}For empty sequence；

2nd step: by S_msIt is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>；

3rd step: by S_hIt is divided intoFour parts, then willI=0,1 ..., 3 are converted to (0,1) In the range of 10 system decimal G_i, i=0,1 ..., 3；

4th step: by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁, G′₂, by G '₀,G′₁,G′₂As key parameter X_init,Y_init,x_init, i.e. X_init=G '₀,Y_init=G '₁,x_init=G '₂, by x_init As sequence S_{X ＞}In kth element

5th step: by initial parameter μ₀As systematic parameter, intermediate parameters x_init5 (0,1) scopes are produced as initial value Interior random number is as sequence S_p=< p₀,p₁,p₂,p₃,p₄>, by S_pInterval division sequence S ' in the range of structure (0,1)_p=p ′₀,p′₁,p′₂,p′₃,p′₄>, thus obtain 6 probability intervals [0, p '₀),[p′₀,p′₁),[p′₁,p′₂),[p′₂,p′₃), [p′₃,p′₄),[p′₄, 1], by p '₀,p′₁,p′₂,p′₃,p′₄As sequence S '_{P ＞}In 5k, 5k+1 ..., 5k+4 element

6th step: by Y_init, μ is mapped as the μ in the range of [3.57,4]₁, by X_initAnd μ₁Respectively as initial value and system Parameter, then the mapping value of iteration 1 time is as intermediate key parameter Z_init；

7th step: by X_init,Y_init,Z_initSubstitute into chaos system for 1 time as initial value iteration and produce 3 real-valued random numbers X₀,Y₀,Z₀, and by X₀,Y₀,Z₀Successively respectively as S_{X ＞},S_{Y ＞},S_{Z ＞}In kth element

8th step: utilize X₀,Y₀,Z₀To event subscript index sequence S_idIt is updated, by S_idIn all elements make successively For S_{Id ＞}In 6k, 6k+1 ..., 6k+5 element

9th step: utilize X₀,Y₀,Z₀To initial parameter μ₀And S_ms=< ms_i>₇₂In element be updated operation；

10th step: if k ≠ t updates k=k+1, repeatedly perform the 2nd step～the 9th step, available sequence $S_{X>}=<X_i^{>}{>}_t,S_Y=<Y_i^{>}{>}_t,S_{Z>}=<Z_i^{>}{>}_t,S_{x>}=<x_i^{>}{>}_t,S_{p>}^{\&prime;}=<p_i^{\&prime;>}{>}_{5t},S_{id>}^{\&prime;}=<{\mathrm{sid}}_i^{>}{>}_{6t};$

11st step: by S_{X ＞},S_{Y ＞}-1 element of kthIt is mapped as image C=(c to be decrypted_i,j)_m×nOn random Point (r₀,v₀), by S_{Z ＞}-1 element of kth in sequenceWithIt is mapped as transformation parameter v；

12nd step: by (r₀,v₀) as starting point, from image C=(c to be decrypted_i,j)_m×nFilter out 4 × 4 matrix fritter M_in= (m_u,w)_4×4, calculate M_inMapping value Map (M_in), if Map is (M_in) >=δ, then update k=k-1, perform the 11st step when k ≠ 0, The 14th step is performed as k=0, if above-mentioned condition Map (M_in) >=δ is not satisfied, and takes S_{X ＞}-1 element of kthSentence as probability Disconnected value P, utilizes S '_{P ＞}5k-5,5k-4 ..., 5k-1 elementStructure probability intervalTake S_{Id ＞}6k-6,6k-5 ..., 6k-1 unit ElementAs subscript index sequence, with v as transformation parameter, the probability interval fallen into according to P, By matrix fritter M_in=(m_u,w)_4×4Deciphering is matrix fritter M_out；

13rd step: calculate M_outCorresponding mapping value Map (M_out), if Map is (M_out) < δ, then by M_outIn element make successively For encrypted image C=(c_i,j)_m×nThe pixel of correspondence position, otherwise by M_inMiddle pixel is as encrypted image C=(c_i,j)_m×nCorresponding The pixel of position, updates k=k-1, repeatedly performs the 11st step～the 13rd step when k ≠ 0；

14th step: by C=(c_i,j)_m×nOutput is as decrypted image.

Further, by S in the 2nd step_msIt is mapped as sequence S_h=< h₀,h₁,…,h₃₉> concrete grammar be formula (1):

S_h=Draw (S_ms,start,gap,|S_h|) (1)

In formula (1), Draw () is that sequential element extracts function, and wherein start is extraction starting point, and gap is the sample skipped Number, | S_h| for S_hMiddle number of elements, i.e. from S_msCirculation extraction | S_h| individual 16 system numbers are as S_h, start, gap are respectively by formula (2) Map with formula (3) and obtain:

$start=\left(\underset{i=0}{\overset{31}{\&Sigma;}}\underset{j=0}{\overset{8}{\&Sigma;}}\right(m_i+s_{i+j}\left)\right)\mathrm{mod}\left|S_{ms}\right|---\left(2\right)$

$gap=\left(\underset{i=0}{\overset{31}{\&Sigma;}}\underset{j=0}{\overset{8}{\&Sigma;}}{m}_i{s}_{i+j}\right)\mathrm{mod}\left|S_{ms}\right|---\left(3\right);$

3rd step is by S_hIt is divided intoTetrameric concrete grammar is formula (4):

$S_{h_i}=<h_i,h_{i+1},...,h_{i+9}>,i=0,1,...,3---\left(4\right);$

3rd step willI=0,1 ..., 3 are converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., the tool of 3 Body method is formula (5):

$G_i=\underset{j=0}{\overset{9}{\&Sigma;}}\&lsqb;10h_{9i+j}/17\&rsqb;\&times;{10}^{-j-1},i=0,1,...,3---\left(5\right);$

4th step is by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁, G′₂Concrete grammar be by G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) iteration and produce 3 sequential values 1 time G′₀,G′₁,G′₂；

$x_{i+1}=\left\{\begin{array}{c}\frac{x_i}{\mathrm{\&alpha;}},0\&le;x_i<\mathrm{\&alpha;}\\ \frac{1-x_i}{1-\mathrm{\&alpha;}},\mathrm{\&alpha;}\&le;x_i<1\end{array}\right.---\left(6\right);$

By μ in 5th step₀As systematic parameter, x_initThe random number in the range of 5 (0,1) is produced as sequence as initial value Row S_p=< p₀,p₁,p₂,p₃,p₄> concrete grammar be as systematic parameter, x using μ 0_initFormula (7) iteration 5 is brought into as initial value Secondary generation sequence S_p=< p₀,p₁,p₂,p₃,p₄>:

x_i+1=μ x_i(1-x_i) (7)；

By S in 5th step_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀,p′₁,p′₂,p′₃,p′₄> tool Body method is by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p′₁,p′₂,p′₃,p′₄>。

Further, the 6th step is by Y_init,μ₀It is mapped as the μ in the range of [3.57,4]₁Concrete grammar be formula (8):

${\mathrm{\&mu;}}_1=\sqrt{(0.43\&times;Y_{init}+3.57)\&CenterDot;{\mathrm{\&mu;}}_0}---\left(8\right)$

6th step is by X_initAnd μ₁Respectively as the mapping value of initial value and systematic parameter iteration 1 time as intermediate key parameter Z_initConcrete grammar be use formula (7):

x_i+1=μ x_i(1-x_i) (7)；

7th step is by X_init,Y_init,Z_initSubstitute into chaos system for 1 time as initial value iteration and produce 3 real-valued random numbers X₀, Y₀,Z₀Concrete grammar be by X_init,Y_init,Z_initAs the initial value of formula (9), formula (9) systematic parameter takes a=b=0.2, c= 5.7, produce 3 real-valued random value X iterative (9) 1 times₀,Y₀,Z₀:

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{X}}_{i+1}=-Y_i-Z_i\\ {\stackrel{\&CenterDot;}{Y}}_{i+1}=X_i+{\mathrm{aY}}_i\\ {\stackrel{\&CenterDot;}{Z}}_{i+1}=b+Z_i(X_i-c)\end{array}\right.---\left(9\right);$

8th step utilizes X₀,Y₀,Z₀To event subscript index sequence S_idThe concrete grammar being updated is for by X₀,Y₀,Z₀By formula (18) and formula (19) is mapped as start, gap, right back-pushed-type (20) is to S_idIt is updated:

S_id=Draw (S_id,start,gap,|S_id|) (20)；

9th step utilizes X₀,Y₀,Z₀To initial parameter μ₀The concrete grammar being updated is formula (22):

${\mathrm{\&mu;}}_0=0.43(\sqrt{X_0{Y}_0}+\sqrt{Z_0{Y}_0}+\sqrt{X_0{Z}_0})\mathrm{mod}1)+3.57---\left(22\right);$

9th step is to S_ms=< ms_i>₇₂In element be updated operation method particularly includes: first use X₀,Y₀,Z₀By formula (21) Generate x_init, then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂ In element be updated operation；

x_init=(X₀+X₀Y₀+X₀Y₀Z₀)mod1 (21)

x_i+1=μ x_i(1-x_i) (7)

Further, by S in the 11st step_{X ＞},S_{Y ＞}-1 element of kthIt is mapped as image C=(c to be decrypted_i,j)_m×n Upper random point (r₀,v₀) concrete grammar be formula (24):

11st step is by S_{Z ＞}-1 element of kth in sequenceWithIt is mapped as the concrete grammar of transformation parameter v For formula (25):

12nd step is by (r₀,v₀) as starting point, from image C=(c to be decrypted_i,j)_m×nFilter out the matrix fritter M of 4 × 4_in =(m_u,w)_4×4Concrete grammar be formula (26):

$m_{u,w}=c_{r_0+u,v_0+w},u,w=0,1,...,3---\left(26\right);$

12nd step calculates M_inMapping value Map (M_in) concrete grammar for calculate M by formula (12)_inCorresponding variance:

$Map\left(M_{in}\right)=\frac{1}{16}\underset{u=0}{\overset{3}{\&Sigma;}}\underset{v=0}{\overset{3}{\&Sigma;}}{(m_{u,v}-\frac{1}{16}\underset{u=0}{\overset{3}{\&Sigma;}}\underset{v=0}{\overset{3}{\&Sigma;}}{m}_{u,v})}^2---\left(12\right);$

By matrix M in 12nd step_in=(m_u,w)_4×4Deciphering is matrix M_outConcrete grammar be formula (27):

M_out=Decryption (M_in,v,P,f′,S_{Id ＞},S′_{P ＞}) (27)

In formula (27), f '={ f '₀,f′₁,…,f′₅It is program event set, f ' corresponding 6 groups of program event, wherein f '₀, f′₁,f′₂Spatial domain displacement box program event, as shown in formula (28), f '₃,f′₄,f′₅Transform domain displacement box program event, such as formula (29) Shown in, f '₀,f′₁,…,f′₅Corresponding displacement box Px₀,Px₁,…,Px₅As shown in formula (17):

$f_i^{\&prime;}:|M_{out}={\mathrm{Permute}}_0^{-1}(M_{in},M_{\mathrm{co}de},{\mathrm{Px}}_i,v),i=0,1,2;M_{code}=\left[\begin{array}{cccc}0& 1& 2& 3\\ 4& 5& 6& 7\\ 8& 9& 10& 11\\ 12& 13& 14& 15\end{array}\right]---\left(28\right)$

In formula (28), M_codeIt is numbering matrix, remembers M_inIn element m_u,wAt Px_iIn numbered id, thenThe function that function performs is by m_u,wMove to M_codeMiddle element number is the coordinate bit of (id-v+16) mod16 Put；

$f_i^{\&prime;}:\left|\begin{array}{c}{M}_{temp}=M_H{M}_{in}{M}_H\\ M_{temp}={\mathrm{Permute}}_1^{-1}(M_{temp},M_{code},{\mathrm{Px}}_i,v)\\ M_{out}=\frac{1}{16}{M}_H{M}_{temp}{M}_H\end{array}\right.,i=3,4,5;M_H=\left[\begin{array}{cccc}1& 1& 1& 1\\ 1& -1& 1& -1\\ 1& 1& -1& -1\\ 1& -1& -1& 1\end{array}\right]---\left(29\right)$

In formula (29), M_HIt is Hadamard transform battle array, Permute₁ ^-1The operation that () performs is by Px_iIn numbered id ≠ × element mt_u,wMove to M_codeIn the coordinate position of numbered (id-v+16) mod16+1, id=× element remain Position is not occurred to change in (0,0) position；

$\begin{array}{c}{\mathrm{Px}}_0=\left[\begin{array}{cccc}15& 14& 13& 12\\ 4& 3& 2& 11\\ 5& 0& 1& 10\\ 6& 7& 8& 9\end{array}\right],{\mathrm{Px}}_1=\left[\begin{array}{cccc}0& 7& 8& 15\\ 1& 6& 9& 14\\ 2& 5& 10& 13\\ 3& 4& 11& 12\end{array}\right],{\mathrm{Px}}_2=\left[\begin{array}{cccc}0& 1& 4& 9\\ 3& 2& 5& 10\\ 8& 7& 6& 11\\ 15& 14& 13& 12\end{array}\right],\\ {\mathrm{Px}}_3=\left[\begin{array}{cccc}\&times;& 2& 8& 10\\ 3& 1& 11& 9\\ 12& 14& 4& 6\\ 15& 13& 7& 5\end{array}\right],{\mathrm{Px}}_4=\left[\begin{array}{cccc}\&times;& 1& 4& 5\\ 3& 2& 7& 6\\ 12& 13& 8& 9\\ 15& 14& 11& 10\end{array}\right],{\mathrm{Px}}_5=\left[\begin{array}{cccc}\&times;& 1& 3& 5\\ 2& 7& 8& 10\\ 4& 9& 12& 13\\ 6& 11& 14& 15\end{array}\right]\end{array}---\left(17\right);$

13rd step calculates M_outCorresponding mapping value Map (M_out) concrete grammar be to calculate by the same method of formula (12) M_outCorresponding variance.

Different compared with technology, advantages of the present invention is mainly reflected in:

1. The present invention gives a kind of selective image encryption compound based on dynamic probability event and null tone territory and deciphering Method, improves carried AES by introducing MD5 value and the SHA-1 value with image to be encrypted attribute extreme sensitivity in plain text Sensitiveness in plain text, and by MD5 value and the compound of SHA-1 value are improved single MD5 value or the crash-protective characteristics of SHA-1 value, institute Extracting method is by the attribute of image to be encrypted, the probability interval fallen into, the encryption link of participation, and corresponding transformation parameter is closely Be coupling in together, even if thus use identical key, different plaintext images is encrypted all by corresponding different adding Close result.

2. convert plaintext into the encryption policy difference of random noise with tradition, designed encryption method only reduces image Visual quality, the approximation characteristic of image can be retained while encryption, and this approximation characteristic can be by set in advance Encryption threshold value is controlled, thus can conveniently treat encrypted image and extract for classifying and knowing another characteristic, simultaneously when deciphering, Encrypted image can recover again in high quality.

The most traditional frequency domain selective cryptographic method may result in spatial domain pixel value when being encrypted frequency coefficient Overflow, thus reduce the visual quality recovering image.Change the impact recovering visual quality of images for reducing frequency coefficient, Present invention adds encryption threshold value screening strategy, for random selected block of pixels being encrypted the screening of before and after's threshold value, once Before and after block of pixels encryption, threshold value screening exceedes threshold value set in advance, then abandon random selected block of pixels is encrypted to ensure that figure Visual quality during as recovering, also retrains the encryption visual quality of image randomized block simultaneously.

What 4. the present invention was given be not only a kind of image encryption method based on probability encryption event, and be a kind of with The image Probabilistic Encryption Methods of update mechanism.Institute's extracting method is key parameter user given and image MD5 to be encrypted, SHA- It is interval that 1 value is mapped as different probability encryptions, is then come to be added by key parameter and MD5 value and SHA-1 value mapping parameters Close pixel carries out random screening, performs different probability encryption events according to the different probability interval fallen into.Institute's extracting method is not Only probability interval is updated, and by mapping parameters, probability encryption arrangement of objects order and initial key is all carried out Update, then the multiplexed sequence being made up of MD5 value and SHA-1 value the initial key generation encryption random sequence after updating is carried out Encryption updates, thus the encrypted state phase that the encrypted event corresponding to different probability intervals is the most incomplete same and the most different Tangle mutually and close-coupled.

Accompanying drawing explanation

Fig. 1 is encryption flow figure；

Fig. 2 is deciphering flow chart；

Fig. 3 is image to be encrypted, is 8 gray level image face of 256 × 256 resolution ratio, and the MD5 value corresponding to Fig. 3 is S_MD5=<D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5,1,4,5,1,3, C, E, F, F, 3,4, E, 4,2,0,7>, SHA-1 Value is S_SHA-1=< 2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9,3,7, C, 1,5,5,7, 0,E,C,2,A,1,E>；

Fig. 4 is embodiment: encrypted image when t=10000, δ=1300, relative to the PSNR=22.939dB of Fig. 3；

Fig. 5 is embodiment: decrypted image when t=10000, δ=1300, relative to the PSNR=50.825dB of Fig. 3；

Fig. 6 is embodiment: encrypted image when t=15000, δ=1600, relative to the PSNR=21.752dB of Fig. 3；

Fig. 7 is embodiment: decrypted image when t=15000, δ=1600, relative to the PSNR=48.276dB of Fig. 3；

Fig. 8 is embodiment: when t=10000, δ=1300, it is provided that corresponding (being revised as 3.989 of the μ value of mistake 3.989999998 decrypted image, relative to the PSNR=21.282dB of Fig. 3)；

Fig. 9 is embodiment: when t=10000, δ=1300, it is provided that the S of mistake_MD5Value (S_MD5=< D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5, Isosorbide-5-Nitrae, 5,1,3, C, E, F, F, 3,4, E, 4,2,0,8 >) corresponding decrypted image, relative to Fig. 3's PSNR=21.278dB；

Figure 10 is embodiment: when t=10000, δ=1300, it is provided that the S of mistake_SHA-1Value (S_SHA-1=< 2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9,3,7, C, 1,5,5,7,0, E, C, 2, A, 1, F >) corresponding solution Close image, is PSNR=21.253dB relative to the PSNR of Fig. 3；

Figure 11 is embodiment: encrypted image when t=10000, δ=2500, relative to the PSNR=22.352dB of Fig. 3；

Figure 12 is embodiment: decrypted image when t=10000, δ=2500, relative to the PSNR=43.642dB of Fig. 3；

Figure 13 is embodiment: encrypted image when t=10000, δ=3500, relative to the PSNR=22.049dB of Fig. 3；

Figure 14 is embodiment: decrypted image when t=10000, δ=3500, relative to the PSNR=46.990dB of Fig. 3；

Figure 15 is embodiment: encrypted image when t=15000, δ=2500, relative to the PSNR=21.415dB of Fig. 3；

Figure 16 is embodiment: decrypted image when t=15000, δ=2500, relative to the PSNR=39.739dB of Fig. 3；

Figure 17 is embodiment: encrypted image when t=15000, δ=3500, relative to the PSNR=21.092dB of Fig. 3；

Figure 18 is embodiment: decrypted image when t=15000, δ=3500, relative to the PSNR=37.506dB of Fig. 3.

Detailed description of the invention

Below in conjunction with specific embodiment, the present invention will be described:

With JAVA jdk1.8.0_20 for case implementation environment, in conjunction with accompanying drawing, embodiment of the present invention is carried out specifically Bright, but it is not limited to the implementation case, wherein Fig. 1 is encryption flow figure, and Fig. 2 is deciphering flow chart；

Ciphering process is as follows:

1st step: choose image A as it is shown on figure 3, be the gray level image face of 256 × 256, remembers image A=to be encrypted (a_i,j)_m×n40 corresponding 16 system MD5 values are S_MD5=< D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5,1,4,5,1, 3, C, E, F, F, 3,4, E, 4,2,0,7 >, SHA-1 value is S_SHA-1=< 2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9,3,7, C, 1,5,5,7,0, E, C, 2, A, 1, E >, by S_MD5And S_SHA-1Series connection is 16 system Number Sequence S_ms =S_MD5||S_SHA-1=< sm_i>₇₂And initialization encryption event subscript index sequence S_idFor S_id=<0,1 ..., 5>, encryption time is set Number t=10000, primary iteration controls parameter k=1, selected initial parameter μ₀=3.989, encrypt judgment threshold δ=1300；

2nd step: by S_msSubstitution formula (1) is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>, by S_msSubstitute into formula respectively And formula (3) is mapped as start, gap (2)；Such as: by S_ms=< D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5,1,4,5, 1,3, C, E, F, F, 3,4, E, 4,2,0,7,2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9,3,7, C, 1,5,5,7,0, E, C, 2, A, 1, E > substitution formula (1) is mapped as S_h=< A, E, 7,2,4,0, A, B, 6,9,0, C, 2, B, 5,4, B, 5, C, F, D, D, C, 1,7,3,1,1, B, 4,1,0,2,1, B, E, 3,7, D, 9 >, by S_msSubstitute into formula (2) and formula respectively (3) start=43, gap=67 can be obtained；

3rd step: by S_hIt is divided into by formula (4)Four parts, then willI=0,1 ..., 3 substitute into Formula (5) is converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., 3；Such as: can be by S_hIt is divided into $S_{h_0}=<A,E,7,2,4,0,A,B,6,9>,S_{h_1}=<0,C,2,B,5,4,B,5,C,F>,S_{h_2}<D,D,C,1,7,3,1,1,B,4>,$ Substitution formula (5) is mapped as: G₀=0.6748477158235295, G₁= 0.07244421382352942,G₂=0.8483371302352942, G₃=0.06013199052941176；

4th step: by G₃As initial parameter α, G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) repeatedly In generation, produces 3 sequential value G ' 1 time₀,G′₁,G′₂, by G '₀,G′₁,G′₂As key parameter X_init,Y_init,x_init；

Such as: α=0.06013199052941176 is as initial parameter, by G₀,G₁,G₂Substitute into formula (6) respectively and map G '₀ =0.34595526276037764, G '₁=0.9869000506772724, G '₂=0.16136613677290165, X_init= 0.34595526276037764,Y_init=0.9869000506772724, x_init=0.16136613677290165；

5th step: by μ₀As systematic parameter, x_init5 random numbers works that formula (7) iteration produces for 5 times are brought into as initial value For sequence S_p=< p₀,p₁,p₂,p₃,p₄>, by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p ′₁,p′₂,p′₃,p′₄>；Such as: μ₀=3.989, x_init=0.16136613677290165 substitutes into formula (7) iteration maps for 5 times, S_p =< p₀,p₁,p₂,p₃,p₄>,p₀=0.5398198285301286, p₁=0.9909249668295106, p₂= 0.035871788327397826,p₃=0.13795957748394325, p₄=0.4743987358004721, then can obtain S '_p =< p '₀,p′₁,p′₂,p′₃,p′₄>, i.e. p '₀=0.035871788327397826, p '₁=0.13795957748394325, p '₂ =0.4743987358004721, p '₃=0.5398198285301286, p '₄=0.9909249668295106；

6th step: by Y_init,μ₀Substitution formula (8) is mapped as μ₁∈ [3.57,4], by X_initAnd μ₁Initial respectively as formula (7) Value and systematic parameter by formula (7) iteration 1 time as intermediate key parameter Z_init；Such as: by μ₀=3.989, Y_init= 0.9869000506772724 substitutes into formula (8) can obtain μ₁=3.9916826088662414, by X_init= 0.34595526276037764 and μ₁=3.9916826088662414 substitute into formula (7) can obtain Z_init= 0.9031988978023509；

7th step: by X_init,Y_init,Z_initAs the initial value of formula (9), produce 3 real-valued random numbers iterative (9) 1 times Successively as parameter X₀,Y₀,Z₀, formula (9) systematic parameter takes a=b=0.2, c=5.7；

Such as: X_init=0.34595526276037764, Y_init=0.9869000506772724, Z_init= 0.9031988978023509 is obtained X by formula (9)₀=0.1755933912994469, Y₀=1.0326377639685018, Z₀= 0.5476634933830886；

8th step: by X₀,Y₀It is A=(a that substitution formula (10) is mapped as encrypted image_i,j)_m×nOn random point (r₀,v₀)；

Such as: X₀=0.1755933912994469, Y₀=1.0326377639685018 substitute into formula (10), can be mapped as Encrypted image is A=(a_i,j)_m×nOn random point r₀=36, v₀=6；

9th step: by (r₀,v₀) as starting point, by formula (11) from image A=(a to be encrypted_i,j)_m×nFilter out M_in= (m_u,w)_4×4, by M_inSubstitution formula (12) calculates mapping value Map (M_in), if Map is (M_in) >=δ then performs the 10th step, otherwise by x_init As probabilistic determination value P, by X₀,Y₀,Z₀Substitution formula (13) mapping transformation parameter v, the probability interval fallen into according to P, by formula (14) corresponding spatial domain and frequency domain displacement cryptographic operation are performed, the method calculating M that right back-pushed-type (12) is same_outMapping value Map (M_out), if Map is (M_out) < δ, then by M_outIn pixel successively as image A=(a to be encrypted_i,j)_m×nThe pixel of correspondence position, Otherwise by M_inMiddle pixel is directly as image A=(a to be encrypted_i,j)_m×nThe pixel of correspondence position；Such as: by (r₀,v₀) as rising Point, by formula (11) from image A=(a to be encrypted_i,j)_m×nFilter out the matrix fritter of 4 × 4 $M_{in}=\left[\begin{array}{cccc}174& 180& 195& 194\\ 149& 165& 183& 189\\ 162& 159& 180& 188\\ 180& 166& 181& 191\end{array}\right],$ By M_inSubstitution formula (12), due to Map (M_in)=172.4375 i.e. Map (M_in) < δ passes through Judge to continue executing with cryptographic operation, P=0.16136613677290165, pass through X₀=0.1755933912994469, Y₀= 1.0326377639685018,Z₀=0.5476634933830886 substitutes into formula (13) mapping transformation parameter v=10, according to P institute The probability interval fallen into, performs corresponding spatial domain by formula (14) and frequency domain displacement cryptographic operation obtains $M_{out}=\left[\begin{array}{cccc}162& 159& 180& 180\\ 188& 180& 166& 195\\ 174& 191& 181& 194\\ 189& 183& 165& 149\end{array}\right],$ By M_outSubstitution formula (12) judges, Map (M_out)=172.4375 i.e. Map (M_out) < δ, then by M_outMiddle element is successively as image A=(a to be encrypted_i,j)_m×nCorrespondence position pixel；

10th step: utilize X₀,Y₀,Z₀Being mapped as start, gap by formula (18) and formula (19), right back-pushed-type (20) is to event Index sequence S_idIt is updated；Such as: by S_id=0,1,2 ..., 5} substitutes into formula (20) and maps new S_id=3,1,0,2,5,4}, By X₀=0.1755933912994469, Y₀=1.0326377639685018, Z₀=0.5476634933830886 substitutes into respectively Formula (18), (19) can obtain parameter start=0, gap=3；

11st step: utilize X₀,Y₀,Z₀Substitution formula (22) maps initial parameter μ₀, then use X₀,Y₀,Z₀Generate by formula (21) x_init, then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂In Element is updated operation；Such as: by X₀,Y₀,Z₀Substitution formula (22) undated parameter μ₀=3.7798190064841766, by X₀, Y₀,Z₀Substitution formula (21) maps x_init=0.45622249450285557, by x_init,μ₀Substitution formula (7) maps random sequence S_R= <r_i>₇₂, and by S_R=< r_i>₇₂To S_ms=< ms_i>₇₂Encrypt the most newly obtained new S_ms=< D, 5,9,2, F, 8, E, 1, D, 1,6, F, E,D,F,D,C,7,F,B,5,6,9,3,C,C,0,D,1,8,0,9,B,D,9,0,F,1,9,8,0,2,A,B,1,9,9,A,F,7, 0,A,E,C,C,B,9,D,E,9,1,8,1,6,E,6,3,5,D,3,E,E>；

12nd step: if during k≤t, updates k=k+1, repeatedly performs the 2nd step～the 11st step；

13rd step: by A=(a_i,j)_m×nOutput is as encrypted image as shown in Figure 4.

Decrypting process is as follows:

1st step: input key μ₀=3.989, encryption number of times t=10000, juxtaposition k=0, input encryption judgment threshold δ= 1300, S_MD5=<D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5, Isosorbide-5-Nitrae, 5,1,3, C, E, F, F, 3,4, E, 4,2,0,7>, S_SHA-1=< 2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9,3,7, C, 1,5,5,7,0, E, C, 2, A, 1, E >, by S_MD5And S_SHA-1Series connection is 16 system Number Sequence S_ms=S_MD5||S_SHA-1=< sm_i>₇₂And initialization encryption thing Part subscript index sequence S_id=<0,1 ..., 5>and intermediate key argument sequence S_{X ＞},S_{Y ＞},S_{Z ＞},S_{X ＞},S′_{P ＞},S_{Id ＞}For empty sequence Row, encrypted image C=(c_i,j)_m×nAs shown in Figure 4；

2nd step: by S_msSubstitution formula (1) is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>, by S_msSubstitute into formula respectively (2) and formula (3) map start, gap；Such as: by S_ms=< D, 1,1, C, B, B, B, C, 3,7, A, A, 8, B, F, 5,1,4,5,1, 3, C, E, F, F, 3,4, E, 4,2,0,7,2, A, E, 0, D, B, A, B, 1,1,6,3,2, E, 8,9, B, 4, A, D, D, 0,7,1, F, 9, 3,7, C, 1,5,5,7,0, E, C, 2, A, 1, E > substitute into formula (1) mapping S_h=< A, E, 7,2,4,0, A, B, 6,9,0, C, 2, B, 5, 4, B, 5, C, F, D, D, C, 1,7,3,1,1, B, 4,1,0,2,1, B, E, 3,7, D, 9 >, wherein by S_msSubstitute into formula (2) and formula respectively (3) start=43, gap=67 are mapped；

3rd step: by S_hIt is divided into by formula (4)Four parts, then willI=0,1 ..., 3 substitute into Formula (5) is converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., 3；Such as: by S_hIt is divided into $S_{h_0}=<A,E,7,2,4,0,A,B,6,9>,S_{h_1}=<0,C,2,B,5,4,B,5,C,F>,S_{h_2}<D,D,C,1,7,3,1,1,B,4>,$ Substitution formula (5) is mapped as G₀=0.6748477158235295, G₁= 0.07244421382352942,G₂=0.8483371302352942, G₃=0.06013199052941176；

4th step: by G₃As initial parameter α, G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) repeatedly In generation, produces 3 sequential value G ' 1 time₀,G′₁,G′₂, by G '₀,G′₁,G′₂As key parameter X_init,Y_init,x_init, by x_initAs Sequence S_{X ＞}In kth elementSuch as: α=0.06013199052941176 is as initial parameter, by G₀,G₁,G₂Respectively Substitution formula (6) is mapped as G '₀=0.34595526276037764, G '₁=0.9869000506772724, G '₂= 0.16136613677290165 i.e. X_init=0.34595526276037764, Y_init=0.9869000506772724, x_init= 0.16136613677290165, by x_initAs sequence S_{X ＞}In kth element

5th step: by μ₀As systematic parameter, x_init5 random numbers works that formula (7) iteration produces for 5 times are brought into as initial value For sequence S_p=< p₀,p₁,p₂,p₃,p₄>, by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p ′₁,p′₂,p′₃,p′₄>, by p '₀,p′₁,p′₂,p′₃,p′₄As sequence S '_{P ＞}In 5k, 5k+1 ..., 5k+4 elementSuch as: μ₀=3.989, x_init=0.16136613677290165 substitutes into formula (7) iteration maps for 5 times S_p=< p₀,p₁,p₂,p₃,p₄>,p₀=0.5398198285301286, p₁=0.9909249668295106, p₂= 0.035871788327397826,p₃=0.13795957748394325, p₄=0.4743987358004721, then can get S′_p=< p '₀,p′₁,p′₂,p′₃,p′₄>, i.e. p '₀=0.035871788327397826, p '₁=0.13795957748394325, p′₂=0.4743987358004721, p '₃=0.5398198285301286, p '₄=0.9909249668295106, by p '₀, p′₁,p′₂,p′₃,p′₄As sequence S '_{P ＞}In 5k, 5k+1 ..., 5k+4 element

6th step: by Y_init,μ₀Substitution formula (8) is mapped as μ₁∈ [3.57,4], by X_initAnd μ₁Respectively as in formula (7) Initial value and systematic parameter by formula (7) iteration 1 time as intermediate key parameter Z_init；Such as: μ₀=3.989, Y_init= 0.9869000506772724 substitutes into formula (8) maps μ₁=3.9916826088662414, by X_init= 0.34595526276037764,μ₁=3.9916826088662414 substitute into formula (7) can obtain: Z_init= 0.9031988978023509；

7th step: by X_init,Y_init,Z_initAs the initial value of formula (9), produce 3 real-valued random numbers iterative (9) 1 times Successively as parameter X₀,Y₀,Z₀, formula (9) systematic parameter takes a=b=0.2, c=5.7, and by X₀,Y₀,Z₀Successively respectively as S_{X ＞},S_{Y ＞},S_{Z ＞}In kth elementSuch as: X_init=0.34595526276037764, Y_init= 0.9869000506772724, Z_init=0.9031988978023509 substitutes into formula (9) iteration maps X 1 time₀= 0.1755933912994469,Y₀=1.0326377639685018, Z₀=0.5476634933830886, by X₀,Y₀,Z₀Successively Respectively as S_{X ＞},S_{Y ＞},S_{Z ＞}In kth element

8th step: utilize X₀,Y₀,Z₀Being mapped as start, gap by formula (18) and formula (19), right back-pushed-type (20) is to event rope Draw sequence S_idIt is updated, by S_idIn all elements successively as S_{Id ＞}In 6k, 6k+1 ..., 6k+5 elementSuch as: by S_id=0,1,2 ..., 5} substitutes into formula (20) and maps new S_id=3,1,0,2,5, 4}, wherein by X₀=0.1755933912994469, Y₀=1.0326377639685018, Z₀=0.5476634933830886 Substituting into formula (18) respectively, (19) mapping parameters start=0, gap=3, by S_idIn all elements successively as S_{Id ＞}In 6k, 6k+1 ..., 6k+5 element

9th step: utilize X₀,Y₀,Z₀Substitution formula (22) maps initial parameter μ₀, then use X₀,Y₀,Z₀X is generated by formula (21)_init, Then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂In element enter Row updates operation；Such as: by X₀,Y₀,Z₀Substitution formula (22) undated parameter μ₀=3.7798190064841766, by X₀,Y₀,Z₀Generation Enter formula (21) and map x_init=0.45622249450285557, by x_init,μ₀Substitution formula (7) maps random sequence S_R=< r_i>₇₂, And by S_R=< r_i>₇₂To S_ms=< ms_i>₇₂Encrypt the most newly obtained new S_ms=< D, 5,9,2, F, 8, E, 1, D, 1,6, F, E, D, F, D,C,7,F,B,5,6,9,3,C,C,0,D,1,8,0,9,B,D,9,0,F,1,9,8,0,2,A,B,1,9,9,A,F,7,0,A,E, C,C,B,9,D,E,9,1,8,1,6,E,6,3,5,D,3,E,E>；

10th step: if k ≠ t updates k=k+1, repeatedly perform the 2nd step～the 9th step, available sequence $S_{X>}=<X_i^{>}{>}_t,S_{Y>}=<Y_i^{>}{>}_t,S_{Z>}=<Z_i^{>}{>}_t,S_{x>}=<x_i^{>}{>}_t,S_{p>}^{\&prime;}=<p_i^{\&prime;>}{>}_{5t},S_{id>}^{\&prime;}=<{\mathrm{sid}}_i^{>}{>}_{6t};$

11st step: by S_{X ＞},S_{Y ＞}-1 element of kthSubstitution formula (24) is mapped as image C=to be decrypted (c_i,j)_m×nOn random point (r₀,v₀), by S_{Z ＞}-1 element of kth in sequenceWithSubstitute into formula (25) together It is mapped as transformation parameter v；Such as: $X_{k-1}^{>}=0.49326206612700085,Y_{k-1}^{>}=0.5897724640770899$ Substitution formula (24) image C=(c to be decrypted is mapped_i,j)_m×nOn random point r₀=238, v₀=52, willWithSubstitution formula (25) maps v=1；

12nd step: by (r₀,v₀) as starting point, by formula (26) from image C=(c to be decrypted_i,j)_m×nFilter out 4 × 4 matrixes Fritter M_in=(m_u,w)_4×4, calculate M by formula (12)_inMapping value Map (M_in), if Map is (M_in) >=δ, then update k when k ≠ 0 =k-1, performs the 11st step, performs the 14th step as k=0, if above-mentioned condition Map (M_in) >=δ is not satisfied, and takes S_{X ＞}Kth-1 ElementAs probabilistic determination value P, utilize S '_{P ＞}5k-5,5k-4 ..., 5k-1 elementStructure Make probability intervalTake S_{Id ＞}6k-6,6k-5 ..., 6k-1 elementAs subscript index sequence, with v as transformation parameter, according to P fallen into general Rate is interval, by formula (27) by matrix fritter M_in=(m_u,w)_4×4Deciphering is matrix fritter M_out；Such as: by (r₀,v₀) as starting point, By formula (26) from image C=(c to be decrypted_i,j)_m×nFilter out the matrix fritter of 4 × 4 $M_{in}=\left[\begin{array}{cccc}112& 126& 128& 133\\ 137& 101& 94& 126\\ 125& 134& 141& 119\\ 97& 127& 122& 90\end{array}\right],$ Will M_inSubstitution formula (12) judges, due to Map (M_in)=239.75 i.e. Map (M_in) ＜ δ, then by S_{X ＞}-1 element of kthMake For probabilistic determination value P=0.31040996788505415, utilize S '_{P ＞}5k-5,5k-4 ..., 5k-1 element $p_{5k-5}^{\&prime;>}=0.011020580623130416,p_{5k-4}^{\&prime;>}=0.04347661930175354,p_{5k-3}^{\&prime;>}=0.49773757775175714$ $p_{5k-2}^{\&prime;>}=0.8538678670736659,p_{5k-1}^{\&prime;>}=0.99872295820863812$ Structure probability intervalTake S_{Id ＞}6k-6,6k-5 ..., 6k-1 unit Element ${\mathrm{sid}}_{6k-6}^{>}=2,{\mathrm{sid}}_{6k-5}^{>}=5,{\mathrm{sid}}_{6k-4}^{>}=4,{\mathrm{sid}}_{6k-3}^{>}=3,{\mathrm{sid}}_{6k-2}^{>}=1,{\mathrm{sid}}_{6k-1}^{>}=0$ Sequence is indexed as subscript Row, with v=1 as transformation parameter, the probability interval fallen into according to P, by matrix fritter M_in=(m_u,w)_4×4Substitution formula (27) solves Close for matrix fritter $M_{out}=\left[\begin{array}{cccc}112& 138& 113& 137\\ 144& 146& 117& 125\\ 123& 114& 107& 95\\ 129& 113& 106& 95\end{array}\right];$

13rd step: the method same by formula (12) calculates M_outCorresponding mapping value Map (M_out), if Map is (M_out) < δ, then By M_outIn element successively as encrypted image C=(c_i,j)_m×nThe pixel of correspondence position, otherwise by M_inMiddle pixel is as encryption Image C=(c_i,j)_m×nThe pixel of correspondence position, updates k=k-1, repeatedly performs the 11st step～the 13rd step when k ≠ 0；Such as: By M_outSubstitution formula (12), due to Map (M_out)=237.484375 i.e. Map (M_out) < δ, then by M_outMiddle pixel is successively as adding Close image C=(c_i,j)_m×nThe pixel of correspondence position；

14th step: by C=(c_i,j)_m×nOutput is as decrypted image as shown in Figure 5.

Fig. 6 is that encryption number of times is respectively t=15000, δ=1600 encrypted image, and Fig. 7 is corresponding decrypted image, can from Fig. 6 Although finding out that the inventive method encrypted image can be with identification relative to artwork, but visual quality entirety is poor, solves as can be seen from Figure 7 Close image is clear relative to artwork visual quality, possesses certain using value；

Fig. 8～10 respectively revises the decrypted image of one of them correspondence；The inventive method is can be seen that from decrypted image, right The key of user's offer and picture characteristics extreme sensitivity to be encrypted, if providing the parameter of mistake, will cause decrypted image vision matter Amount declines, and decrypted image visual quality is the fuzzyyest；

Figure 11,13,15,17 is different encryption number of times t respectively, encrypted image embodiment corresponding during δ, Figure 12,14, 16,18 is corresponding decrypted image embodiment, can be seen that from decrypted image visual quality, by controlling t, δ, available The decrypted image of different visual qualities, thus possess the most wide using value.

Claims (10)

1. the image selective cryptographic method that a dynamic probability and null tone territory are combined, it is characterised in that comprise the following steps:

1st step: remember that image to be encrypted is A=(a_i,j)_m×nAnd a_i,j∈ 0,1 ..., and 255}, encryption number of times t, t ＞ 0 are set, initially Iteration control parameter k=1, selected initial parameter μ₀∈ [3.57,4] and setting encryption judgment threshold δ, δ ＞ 0, the MD5 of note A Value and SHA-1 value are respectively 16 system Number Sequence S_MD5=< m₀,m₁,…,m₃₁> and S_SHA-1=< s₀,s₁,…,s₃₉>, by S_MD5With S_SHA-1Series connection is 16 system Number Sequence S_ms=S_MD5||S_SHA-1=< sm_i>₇₂And initialization encryption event subscript index sequence S_idFor S_id=<0,1 ..., 5>, wherein " | | " it is bit bit string serial operation symbol；

2nd step: by S_msIt is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>；

3rd step: by S_hIt is divided intoFour parts, then willBe converted to 10 in the range of (0,1) System decimal G_i, i=0,1 ..., 3；

4th step: by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁,G′₂, By G '₀,G′₁,G′₂As key parameter X_init,Y_init,x_init, i.e. X_init=G '₀,Y_init=G '₁,x_init=G '₂；

5th step: by initial parameter μ₀As systematic parameter, key parameter x_initIn the range of producing 5 (0,1) as initial value Random number is as sequence S_p=< p₀,p₁,p₂,p₃,p₄>, by S_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀, p′₁,p′₂,p′₃,p′₄>, thus obtain probability interval [0, p '₀),[p′₀,p′₁),[p′₁,p′₂),[p′₂,p′₃),[p′₃,p′₄), [p′₄,1]；

6th step: by key parameter Y_init,μ₀It is mapped as μ₁∈ [3.57,4], by X_initAnd μ₁Join respectively as initial value and system Number iteration produces intermediate key parameter Z in the range of (0,1)_init；

7th step: by X_init,Y_init,Z_initAs initial value, iteration produces 3 real-valued random numbers for 1 time successively as parameter X₀,Y₀, Z₀；

8th step: by X₀,Y₀It is mapped as encrypted image A=(a_i,j)_m×nOn random point (r₀,v₀)；

9th step: by (r₀,v₀) as starting point, from image A=(a to be encrypted_i,j)_m×nFilter out M_in=(m_u,w)_4×4, calculate M_in's Mapping value Map (M_in), if Map is (M_in) >=δ then performs the 10th step, otherwise by x_initAs probabilistic determination value P, by X₀,Y₀,Z₀'s Mapping value, as transformation parameter v, the probability interval fallen into according to P, performs corresponding spatial domain and frequency domain displacement cryptographic operation, so Afterwards to the matrix fritter M after encryption_outCalculate mapping value Map (M_out)；If Map is (M_out) < δ, then by M_outIn pixel make successively For image A=(a to be encrypted_i,j)_m×nThe pixel of correspondence position, otherwise by M_inMiddle pixel is directly as image A=to be encrypted (a_i,j)_m×nCorrespondence position pixel；

10th step: utilize X₀,Y₀,Z₀To case index sequence S_idCarry out resetting and update；

11st step: utilize X₀,Y₀,Z₀To initial parameter μ₀And S_ms=< ms_i>₇₂In element be updated operation；

12nd step: if during k≤t, updates k=k+1, repeatedly performs the 2nd step～the 11st step；

13rd step: by A=(a_i,j)_m×nOutput is as encrypted image.

The image selective cryptographic method that a kind of dynamic probability the most as claimed in claim 1 and null tone territory are combined, its feature exists In: the 2nd step is by S_msIt is mapped as S_h=< h₀,h₁,…,h₃₉> concrete grammar be formula (1):

S_h=Draw (S_ms,start,gap,|S_h|) (1)

In formula (1), Draw () is that sequential element extracts function, and wherein start is extraction starting point, and gap is the sample number skipped, | S_h | for S_hMiddle number of elements, i.e. from S_msCirculation extraction | S_h| individual 16 system numbers are as S_h, start, gap are respectively by formula (2) and formula (3) Mapping obtains:

3rd step is by S_hIt is divided intoTetrameric concrete grammar is formula (4):

3rd step willBe converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., the concrete grammar of 3 is Formula (5), in formula (5), [] is round function:

The image selective cryptographic method that a kind of dynamic probability the most as claimed in claim 1 and null tone territory are combined, its feature exists In: the 4th step is by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁,G′₂'s Concrete grammar is by G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) iteration and produce 3 sequential value G ' 1 time₀, G′₁,G′₂；

5th step is by μ₀As systematic parameter, x_initThe random number in the range of 5 (0,1) is produced as sequence S as initial value_p= <p₀,p₁,p₂,p₃,p₄> concrete grammar be by μ₀As systematic parameter, x_initBring formula (7) iteration into as initial value to produce for 5 times 5 random numbers as sequence S_p=< p₀,p₁,p₂,p₃,p₄>

x_i+1=μ x_i(1-x_i) (7)；

By S in 5th step_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀,p′₁,p′₂,p′₃,p′₄> concrete grammar For by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p′₁,p′₂,p′₃,p′₄>。

The image selective cryptographic method that a kind of dynamic probability the most as claimed in claim 1 and null tone territory are combined, its feature exists In: the 6th step is by Y_init,μ₀It is mapped as μ₁The concrete grammar of ∈ [3.57,4] is formula (8):

6th step is by X_initAnd μ₁The intermediate key parameter in the range of (0,1) is produced respectively as initial value and systematic parameter iteration Z_initConcrete grammar be by X_initAnd μ₁1 conduct of formula (7) iteration is pressed respectively as the initial value in formula (7) and systematic parameter Intermediate key parameter Z_init；

x_i+1=μ x_i(1-x_i) (7)；

7th step is by X_init,Y_init,Z_initAs initial value, iteration produces 3 random numbers for 1 time successively as parameter X₀,Y₀,Z₀'s Concrete grammar is by X_init,Y_init,Z_initAs the initial value of formula (9), produce 3 random number conducts successively iterative (9) 1 times Parameter X₀,Y₀,Z₀, formula (9) systematic parameter takes a=b=0.2, c=5.7；

The image selective cryptographic method that a kind of dynamic probability the most as claimed in claim 1 and null tone territory are combined, its feature exists In: the 8th step is by X₀,Y₀Being mapped as encrypted image is A=(a_i,j)_m×nOn random point (r₀,v₀) concrete grammar be formula (10), In formula (10)Accord with for downward rounding operation；

9th step is by (r₀,v₀) as starting point, from image A=(a to be encrypted_i,j)_m×nFilter out the matrix fritter M of 4 × 4_in= (m_u,w)_4×4Concrete grammar be formula (11):

9th step calculates M_inMapping value Map (M_in) concrete grammar be by formula (12) calculate M_inVariance:

9th step is to the matrix fritter M after encryption_outCalculate mapping value Map (M_out) concrete grammar be the side same by formula (12) Method calculates M_outVariance；

By X in 9th step₀,Y₀,Z₀Mapping value be formula (13) as the concrete grammar of transformation parameter v:

9th step performs the spatial domain of correspondence and the concrete grammar of frequency domain displacement cryptographic operation is formula (14):

M_out=Encrypt (M_in,v,P,f,S_id,S′_p) (14)

In formula (14), f={f₀,f₁,…,f₅It is encrypted event set, S_idIt is the subscript index sequence of f, S '_pFor interval division Sequence, corresponding 6 group encryption event, the wherein f of encrypted event set f₀,f₁,f₂Spatial domain displacement box encrypted event, as shown in formula (15), f₃,f₄,f₅Transform domain displacement box encrypted event, as shown in formula (16), f₀,f₁,…,f₅Corresponding displacement box Px₀,Px₁,…, Px₅As shown in formula (17)；

In formula (15), M_codeIt is M_inNumbering matrix, remember M_inIn element m_u,wAt M_codeIn numbered id, then Permute₀() The function that function performs is by m_u,wMove to Px_iMiddle element value is the coordinate position of (id+v) mod16；

In formula (16), M_HIt is Hadamard transform battle array, remembers M_tempIn element mt_u,wAt M_codeIn numbered id and id ≠ ×, Permute₁The operation that () performs is by mt_u,wMove to Px_iMiddle element value is the coordinate position of (id+v) mod16+1, with Permute₀The difference of () is Permute₁() in conversion process, M_tempIn the element of (0,0) position, i.e. id=× element Remaining at (0,0) position does not occur position to change；

The image selective cryptographic method that a kind of dynamic probability the most as claimed in claim 1 and null tone territory are combined, its feature exists In: the 10th step utilizes X₀,Y₀,Z₀To case index sequence S_idCarry out resetting the concrete grammar updated for by X₀,Y₀,Z₀By formula (18) Being mapped as start, gap with formula (19), right back-pushed-type (20) is to case index sequence S_idIt is updated:

S_id=Draw (S_id,start,gap,|S_id|) (20)；

11st step utilizes X₀,Y₀,Z₀To initial parameter μ₀The concrete grammar updated is formula (22):

To S in 11st step_ms=< ms_i>₇₂In element be updated operation method particularly includes: first use X₀,Y₀,Z₀By formula (21) Generate x_init, then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂ In element be updated operation；

x_init=(X₀+X₀Y₀+X₀Y₀Z₀)mod1 (21)

x_i+1=μ x_i(1-x_i) (7)

7. the image selectivity decryption method that a kind of dynamic probability corresponding with claim 1 and null tone territory are combined, its feature It is to comprise the following steps:

1st step: inputted key μ by user₀∈[3.57,4],S_MD5,S_SHA-1, encrypt number of times t, t ＞ 0 and encrypted image C, initially Iteration control parameter k=0, input encryption judgment threshold δ, δ ＞ 0, by S_MD5And S_SHA-1Series connection is 16 system Number Sequence S_ms=S_MD5 ||S_SHA-1=< sm_i>₇₂And initialization encryption event subscript index sequence S_id=<0,1 ..., 5>and intermediate key argument sequence S_{X ＞},S_{Y ＞},S_{Z ＞},S_{X ＞},S′_{P ＞},S_{Id ＞}For empty sequence；

2nd step: by S_msIt is mapped as 16 system sequences S_h=< h₀,h₁,…,h₃₉>；

3rd step: by S_hIt is divided intoFour parts, then willBe converted to 10 in the range of (0,1) System decimal G_i, i=0,1 ..., 3；

4th step: by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G in the range of (0,1)₀′,G₁′,G₂', By G₀′,G₁′,G₂' as key parameter X_init,Y_init,x_init, i.e. X_init=G '₀,Y_init=G '₁,x_init=G '₂, by x_initMake For sequence S_{X ＞}In kth element

5th step: by μ₀As systematic parameter, x_initThe random number in the range of 5 (0,1) is produced as sequence S as initial value_p =< p₀,p₁,p₂,p₃,p₄>, by S_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀,p′₁,p′₂,p′₃,p′₄>, from And obtain 6 probability intervals [0, p '₀),[p′₀,p′₁),[p′₁,p′₂),[p′₂,p′₃),[p′₃,p′₄),[p′₄, 1], by p '₀, p′₁,p′₂,p′₃,p′₄As sequence S '_{P ＞}In 5k, 5k+1 ..., 5k+4 element

6th step: by Y_init, μ is mapped as the μ in the range of [3.57,4]₁, by X_initAnd μ₁Change respectively as initial value and systematic parameter In generation, the mapping value of 1 time was as intermediate key parameter Z_init；

7th step: by X_init,Y_init,Z_initSubstitute into chaos system for 1 time as initial value iteration and produce 3 real-valued random numbers X₀,Y₀, Z₀, and by X₀,Y₀,Z₀Successively respectively as S_{X ＞},S_{Y ＞},S_{Z ＞}In kth element

8th step: utilize X₀,Y₀,Z₀To event subscript index sequence S_idIt is updated, by S_idIn all elements conduct successively S_{Id ＞}In 6k, 6k+1 ..., 6k+5 element

9th step: utilize X₀,Y₀,Z₀To initial parameter μ₀And S_ms=< ms_i>₇₂In element be updated operation；

10th step: if k ≠ t updates k=k+1, repeatedly perform the 2nd step～the 9th step, available sequence

11st step: by S_{X ＞},S_{Y ＞}-1 element of kthIt is mapped as image C=(c to be decrypted_i,j)_m×nOn random point (r₀,v₀), by S_{Z ＞}-1 element of kth in sequenceWithIt is mapped as transformation parameter v；

12nd step: by (r₀,v₀) as starting point, from image C=(c to be decrypted_i,j)_m×nFilter out 4 × 4 matrix fritter M_in= (m_u,w)_4×4, calculate M_inMapping value Map (M_in), if Map is (M_in) >=δ, then update k=k-1, perform the 11st step when k ≠ 0, The 14th step is performed as k=0, if above-mentioned condition Map (M_in) >=δ is not satisfied, and takes S_{X ＞}-1 element of kthAs probability Judgment value P, utilizes S '_{P ＞}5k-5,5k-4 ..., 5k-1 elementStructure probability intervalTake S_{Id ＞}6k-6,6k-5 ..., 6k-1 unit ElementAs subscript index sequence, with v as transformation parameter, the Probability Region fallen into according to P Between, by matrix fritter M_in=(m_u,w)_4×4Deciphering is matrix fritter M_out；

13rd step: calculate M_outCorresponding mapping value Map (M_out), if Map is (M_out) < δ, then by M_outIn element successively as adding Close image C=(c_i,j)_m×nThe pixel of correspondence position, otherwise by M_inMiddle pixel is as encrypted image C=(c_i,j)_m×nCorrespondence position Pixel, update k=k-1 when k ≠ 0, repeatedly perform the 11st step～the 13rd step；

14th step: by C=(c_i,j)_m×nOutput is as decrypted image.

The image selectivity decryption method that a kind of dynamic probability the most as claimed in claim 7 and null tone territory are combined, its feature exists In: by S in the 2nd step_msIt is mapped as sequence S_h=< h₀,h₁,…,h₃₉> concrete grammar be formula (1):

S_h=Draw (S_ms,start,gap,|S_h|) (1)

In formula (1), Draw () is that sequential element extracts function, and wherein start is extraction starting point, and gap is the sample number skipped, | S_h | for S_hMiddle number of elements, i.e. from S_msCirculation extraction | S_h| individual 16 system numbers are as S_h, start, gap are respectively by formula (2) and formula (3) Mapping obtains:

3rd step is by S_hIt is divided intoTetrameric concrete grammar is formula (4):

3rd step willBe converted to 10 system decimal G in the range of (0,1)_i, i=0,1 ..., the concrete grammar of 3 is Formula (5):

4th step is by G₃As initial parameter α, G₀,G₁,G₂It is mapped as 10 system decimal G ' in the range of (0,1)₀,G′₁,G′₂'s Concrete grammar is by G₀,G₁,G₂Respectively as the input parameter of formula (6), substitute into formula (6) iteration and produce 3 sequential value G ' 1 time₀, G′₁,G′₂；

By μ in 5th step₀As systematic parameter, x_initThe random number in the range of 5 (0,1) is produced as sequence S as initial value_p =< p₀,p₁,p₂,p₃,p₄> concrete grammar be by μ₀As systematic parameter, x_initBring formula (7) iteration into as initial value to produce for 5 times Raw sequence S_p=< p₀,p₁,p₂,p₃,p₄>:

x_i+1=μ x_i(1-x_i) (7)；

By S in 5th step_pInterval division sequence S ' in the range of structure (0,1)_p=< p '₀,p′₁,p′₂,p′₃,p′₄> concrete grammar For by S_pMiddle element obtains interval division sequence S ' by descending order_p=< p '₀,p′₁,p′₂,p′₃,p′₄>。

9., as claimed in claim 7 based on the image selectivity decryption method that dynamic probability and null tone territory are compound, its feature exists In: the 6th step is by Y_init,μ₀It is mapped as the μ in the range of [3.57,4]₁Concrete grammar be formula (8):

6th step is by X_initAnd μ₁Respectively as the mapping value of initial value and systematic parameter iteration 1 time as intermediate key parameter Z_init Concrete grammar be use formula (7):

x_i+1=μ x_i(1-x_i) (7)；

7th step is by X_init,Y_init,Z_initSubstitute into chaos system for 1 time as initial value iteration and produce 3 real-valued random numbers X₀,Y₀,Z₀ Concrete grammar be by X_init,Y_init,Z_initAs the initial value of formula (9), formula (9) systematic parameter takes a=b=0.2, c=5.7, Produce 3 real-valued random value X iterative (9) 1 times₀,Y₀,Z₀:

8th step utilizes X₀,Y₀,Z₀To event subscript index sequence S_idThe concrete grammar being updated is for by X₀,Y₀,Z₀By formula (18) Being mapped as start, gap with formula (19), right back-pushed-type (20) is to S_idIt is updated:

S_id=Draw (S_id,start,gap,|S_id|) (20)；

9th step utilizes X₀,Y₀,Z₀To initial parameter μ₀The concrete grammar being updated is formula (22):

9th step is to S_ms=< ms_i>₇₂In element be updated operation method particularly includes: first use X₀,Y₀,Z₀Generate by formula (21) x_init, then by x_init,μ₀Substitution formula (7) iteration produces random sequence S_R=< r_i>₇₂, by formula (23) to S_ms=< ms_i>₇₂In Element is updated operation；

x_init=(X₀+X₀Y₀+X₀Y₀Z₀)mod1 (21)

x_i+1=μ x_i(1-x_i) (7)

The image selectivity decryption method that a kind of dynamic probability the most as claimed in claim 7 and null tone territory are combined, its feature exists In: by S in the 11st step_{X ＞},S_{Y ＞}-1 element of kthIt is mapped as image C=(c to be decrypted_i,j)_m×nUpper random point (r₀, v₀) concrete grammar be formula (24):

11st step is by S_{Z ＞}-1 element of kth in sequenceWithThe concrete grammar being mapped as transformation parameter v is formula (25):

12nd step is by (r₀,v₀) as starting point, from image C=(c to be decrypted_i,j)_m×nFilter out the matrix fritter M of 4 × 4_in= (m_u,w)_4×4Concrete grammar be formula (26):

12nd step calculates M_inMapping value Map (M_in) concrete grammar for calculate M by formula (12)_inCorresponding variance:

By matrix M in 12nd step_in=(m_u,w)_4×4Deciphering is matrix M_outConcrete grammar be formula (27):

M_out=Decryption (M_in,v,P,f′,S_{Id ＞},S′_{P ＞}) (27)

In formula (27), f '={ f '₀,f′₁,…,f′₅It is program event set, f ' corresponding 6 groups of program event, wherein f '₀,f′₁, f′₂Spatial domain displacement box program event, as shown in formula (28), f '₃,f′₄,f′₅Transform domain displacement box program event, such as formula (29) institute Show, f '₀,f′₁,…,f′₅Corresponding displacement box Px₀,Px₁,…,Px₅As shown in formula (17):

In formula (28), M_codeIt is numbering matrix, remembers M_inIn element m_u,wAt Px_iIn numbered id, thenLetter The function that number performs is by m_u,wMove to M_codeMiddle element number is the coordinate position of (id-v+16) mod16；

In formula (29), M_HIt is Hadamard transform battle array, Permute₁ ^-1The operation that () performs is by Px_iIn numbered id ≠ × Element mt_u,wMove to M_codeIn the coordinate position of numbered (id-v+16) mod16+1, id=× element remain at (0,0) position does not occur position to change；

13rd step calculates M_outCorresponding mapping value Map (M_out) concrete grammar be to calculate M by the same method of formula (12)_outInstitute Corresponding variance.