CN103593590B - Based on mixing additivity repeatedly watermark embedding method and the coding/decoding method of cloud environment - Google Patents

Abstract

The invention provides the mixing additivity repeatedly watermark embedding method based on cloud environment, the cross-reference of two kinds of different additivity rules is controlled by key, realize the repeatedly embedding of digital watermarking, because embedding method controls by algorithm control key, the security of therefore more traditional additive watermarks system is higher, and robustness is good.The digital watermarking of embedding is decoded to application two kinds different additive insertion rule to present invention also offers same decoding algorithm of the present invention.Owing to employing two class keys, algorithm control key, watermark information encryption key and watermark embedment repeatedly, therefore the present invention to can be implemented in cloud environment many people to the control of system.

Description

Based on mixing additivity repeatedly watermark embedding method and the coding/decoding method of cloud environment

Technical field

The invention belongs to computer information safety technique field, especially relate to and a kind ofly mix additivity repeatedly embed watermark method and corresponding coding/decoding method.

Background technology

Along with popularizing of the arrival of information age, particularly Internet, the safety protection problem of information becomes increasingly conspicuous.Current information security technology is substantially all based on cryptography theory, and no matter be adopt traditional cipher key system or public key cryptosyst, its protected mode is all the access of control documents, becomes ciphertext by file encryption, and disabled user can not be understood.But along with the quick raising of computer process ability, this method improving system level of confidentiality by constantly increasing key length becomes more and more dangerous.On the other hand, multimedia technology is widely used, needs to be encrypted, the audio-visual-data of certification and copyright protection also gets more and more.Digitized audio-visual-data is exactly digital signal in essence, if also adopt password encryption mode to this kind of data, then the signal attribute of itself has just been left in the basket.Recent years, many researchists abandon the technology path of traditional cryptography, attempt carrying out concealed encrypted with various signal processing method to audio-visual-data, and this technology are used for making multimedia " digital watermarking ".

The proposition of digital watermark method is the problem such as copyright protection, traitor tracing in order to solve multi-medium data, not only needs the safety of copyright information but also comprises the safety of watermarking algorithm itself.At present, although a large amount of Digital Watermark Schemes is suggested, the security of the embedded mobile GIS of these conventional digital watermarking projects itself needs to improve further, and especially additive watermarks algorithm, itself is also subject to cipher controlled, and therefore its security also has problems.Traditional additivity digital watermarking system is made up of two parts such as general additive watermarks embedding and general additive watermarks decodings usually, and as shown in Figure 1, being embedded by general additive watermarks will by key K _wthe watermark information W of encryption is embedded in initial carrier C, exports the carrier containing watermark.The carrier received, namely may be under attack containing watermark carrier, encrypts the watermark information W produced to combine to detect in carrier whether embed watermark information by general additive watermarks decoding and key K w.We find, traditional additivity digital watermark method has many defects: general additive watermarks embedded mobile GIS does not receive cipher controlled due to itself, and therefore algorithm itself lacks security, and this just brings potential safety hazard to watermark information; In addition, because traditional additive watermarks scheme only uses single key K w, be therefore difficult to realize in cloud environment many people to the co-controlling of scheme.

Summary of the invention

For solving the problem, the invention discloses a kind of digital watermark method using two kinds of regular repeatedly embed watermark informations of different additive insertion and the coding/decoding method corresponded, there is higher security.

In order to achieve the above object, the invention provides following technical scheme:

Based on a mixing additivity repeatedly watermark embedding method for cloud environment, comprise the steps:

The transform method that steps A adopts conversion coefficient to meet generalized Gaussian distribution converts initial carrier;

Step B is by algorithm control key K _aproduce the algorithm be made up of 1 and 0 and control random series B, algorithm controls the figure place × embedding number of times of the length=digital watermark information of random series B;

Watermark information is embedded in the carrier after being converted by steps A by following formula by step C:

$y_i=x_i+\underset{j=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{\α}}_{\mathrm{ij}}\mathrm{sign}{\left(x_i\right)}^{b_{\mathrm{ij}}}{s}_t{w}_{\mathrm{ij}}$

Wherein, w _ij∈ P represents by encryption key K _wthe pseudo-random sequence of encryption, b _ij∈ B represents by algorithm control key K _athe algorithm control sequence produced, the number of times of K representative digit watermark embedment, x _i∈ X represents the conversion coefficient of initial carrier, y _i∈ Y represents the conversion coefficient containing watermark carrier, α _ijthe embedment strength of ∈ α representative digit watermark, s _t∈ S represents copyright information.

As a kind of preferred version of embed watermark method, described transform method is discrete small wave converting method.

Based on a mixing additivity repeatedly watermark decoding method for cloud environment, comprise the steps:

Steps A receives the image of the mixing additivity repeatedly watermark embedding method embed watermark utilized based on cloud environment;

The transform method that step B adopts conversion coefficient to meet generalized Gaussian distribution converts image, and described transform method is identical with the transform method adopted in watermark embedding method;

Step C adopts following formula to be watermark decode:

$\mathrm{\Λ}\left(y\right)=\underset{i=1}{\overset{L}{\mathrm{\Σ}}}\underset{j=1}{\overset{K}{\mathrm{\Σ}}}{c}_i|y_i{|}^{(c_i-1)}{\mathrm{\β}}^{c_i}{\mathrm{\α}}_{\mathrm{ij}}\mathrm{sign}{\left(y_i\right)}^{(b_{\mathrm{ij}}+1)}{w}_{\mathrm{ij}};$

Wherein, l is the spread spectrum dimension of copyright information, c _ibe the form parameter of generalized Gaussian distribution, σ is the standard variance of generalized Gaussian distribution function, and Γ (x) is gamma function;

In step D step C, formula is decoded as following formula:

$s_t=\left\{\begin{array}{c}1,\mathrm{\&Lambda;}\left(y\right)>0\\ 0,\mathrm{\&Lambda;}\left(y\right)<0\end{array}\right..$

As a kind of preferred version of coding/decoding method, described transform method is discrete small wave converting method.

The invention has the advantages that: provide the mixing additivity repeatedly watermark embedding method based on cloud environment, the cross-reference of two kinds of different additivity rules is controlled by key, realize the repeatedly embedding of digital watermarking, because embedding method controls by algorithm control key, the security of therefore more traditional additive watermarks system is higher, and robustness is good.The digital watermarking of embedding is decoded to application two kinds different additive insertion rule to present invention also offers same decoding algorithm of the present invention.Owing to employing two class keys, algorithm control key, watermark information encryption key and watermark embedment repeatedly, therefore the present invention to can be implemented in cloud environment many people to the control of system.

Accompanying drawing explanation

Fig. 1 is that traditional additive watermarks embeds and decoding process;

Fig. 2 is mixing additivity provided by the invention repeatedly watermark embedment and decoding process;

Fig. 3 is two kinds of initial carriers not containing watermark;

Fig. 4 is that traditional general additive watermarks embeds, the security performance contrast schematic diagram of coding/decoding method and mixing additivity repeatedly watermark embedment, coding/decoding method;

Fig. 5 is that traditional general additive watermarks embeds, the robustness contrast schematic diagram of coding/decoding method and mixing additivity repeatedly watermark embedment, coding/decoding method.

Embodiment

Below with reference to specific embodiment, technical scheme provided by the invention is described in detail, following embodiment should be understood and be only not used in for illustration of the present invention and limit the scope of the invention.

The invention provides a kind of mixing additivity based on cloud environment repeatedly watermark embedding method and corresponding watermark decoding method, employ two class keys: algorithm control key and watermark information encryption key, and carry out repeatedly watermark embedment, its flow process as shown in Figure 2.

Wherein, mixing additivity repeatedly watermark embedding method uses two kinds of different additive insertion rules simultaneously, i.e. conventional additivity rule and symbol additivity rule, and the cross-reference of control law is carried out by key, thus not homotactic digital watermarking is repeatedly embedded in initial carrier.Specifically, comprise the steps:

The transform method that steps A adopts conversion coefficient to meet generalized Gaussian distribution converts initial carrier, and in this example, we use discrete small wave converting method, and namely DWT converts initial carrier, and its conversion coefficient meets generalized Gaussian distribution (GGD).

Step B is by algorithm control key K _aproduce the algorithm be made up of 1 and 0 and control random series B, algorithm controls the figure place × embedding number of times of the length=digital watermark information of random series B; Wherein digital watermark information is by copyright protection information or digital finger-print information S and encryption key K _wformed after the pseudo-random sequence P spread spectrum of encryption, therefore the figure place of digital watermark information is exactly the figure place after copyright protection information or digital finger-print information S spread spectrum.Embed number of times and can determine such as have three copyright persons namely to embed three times according to the quantity of copyright owner; Number of times can certainly be embedded by sets itself as required.

Watermark information is embedded in the carrier after being converted by steps A by step C.Two kinds of keys are employed: by encryption key K in this step _wthe digital watermark information that encryption embeds, and by algorithm control key K _athe additive insertion rule that employing two kinds in control telescopiny is different, concrete embedding formula is as follows:

$y_i=x_i+\underset{j=1}{\overset{K}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;}}_{\mathrm{ij}}\mathrm{sign}{\left(x_i\right)}^{b_{\mathrm{ij}}}{s}_t{w}_{\mathrm{ij}}$

Wherein, w _ij∈ P represents by encryption key K _wthe pseudo-random sequence of encryption, this pseudo-random sequence meets and is uniformly distributed; The number of times of K representative digit watermark embedment; x _i∈ X represents the conversion coefficient of initial carrier; y _i∈ Y represents the conversion coefficient containing watermark carrier; α _ijthe embedment strength of ∈ α representative digit watermark; s _t∈ S represents that value is the copyright information of 0 or 1; b _ij∈ B represents by algorithm control key K _athe algorithm control sequence produced.Due to B to be value be 0 or 1 random algorithm control sequence, work as b _ijwhen value is 1, i.e. is-symbol additive insertion rule; Work as b _ijwhen value is 0, it is namely conventional additive insertion rule.

Said method is at algorithm control key K _acontrol under two kinds of different additivity rules are controlled, will by encryption key K _wthe digital watermark information of encryption is embedded in the initial carrier of input, thus obtain exporting containing watermark carrier.

Accordingly, present invention also offers a kind of mixing additivity repeatedly watermark decoding method based on cloud environment, comprise the steps:

First steps A receives the image of the mixing additivity repeatedly watermark embedding method embed watermark utilized based on cloud environment;

The transform method that step B adopts conversion coefficient to meet generalized Gaussian distribution converts image, and because the transform method in aforementioned watermark embedding method uses discrete small wave converting method, therefore during decoding, we adopt discrete small wave converting method too.

Step C adopts detection algorithm to be watermark decode, and formula is as follows:

$\mathrm{\&Lambda;}\left(y\right)=\underset{i=1}{\overset{L}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{K}{\mathrm{\&Sigma;}}}{c}_i|y_i{|}^{(c_i-1)}{\mathrm{\&beta;}}^{c_i}{\mathrm{\&alpha;}}_{\mathrm{ij}}\mathrm{sign}{\left(y_i\right)}^{(b_{\mathrm{ij}}+1)}{w}_{\mathrm{ij}};$

Wherein, l is the spread spectrum dimension of copyright information, c _ibe the form parameter of generalized Gaussian distribution, the difference of carrier can cause the different σ of c to be the standard variance of generalized Gaussian distribution function, gamma function.In step D step C, formula is decoded as following formula:

$s_t=\left\{\begin{array}{c}1,\mathrm{\&Lambda;}\left(y\right)>0\\ 0,\mathrm{\&Lambda;}\left(y\right)<0\end{array}\right..$

Coding/decoding method is by algorithm control key K _a, and utilize detecting device and encryption key K _wwhether the digital watermark information W of encryption combines, to carry out watermark decode to the carrier received, thus judge in carrier containing copyright information S.

In order to illustrate advantage of the present invention, we adopt respectively traditional general additive watermarks embedding grammar and mixing additivity provided by the invention repeatedly watermark embedding method carry out watermark embedding operation with for identical carrier (as shown in Figure 3), and adopt corresponding demoder (namely to adopt general additive watermarks coding/decoding method to decode by the carrier of general additive watermarks embedding grammar embed watermark respectively, by mixing additivity repeatedly watermark embedding method embed watermark carrier adopt mixing additivity repeatedly watermark decoding method decode) carry out watermark decode, carry out robustness for decoded result and compare (as shown in Figure 4) and security contrast (as shown in Figure 5).Clearly, the security of watermark embedment is high, robustness good, is obviously better than classic method to adopt the inventive method to carry out.

Technological means disclosed in the present invention program is not limited only to the technological means disclosed in above-mentioned embodiment, also comprises the technical scheme be made up of above technical characteristic combination in any.It should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.

Claims (4)

1., based on a mixing additivity repeatedly watermark embedding method for cloud environment, it is characterized in that, comprise the steps:

The transform method that steps A adopts conversion coefficient to meet generalized Gaussian distribution converts initial carrier;

Step B is by algorithm control key K _aproduce the algorithm be made up of 1 and 0 and control random series B, algorithm controls the figure place × embedding number of times of the length=digital watermark information of random series B;

Watermark information is embedded in the carrier after being converted by steps A by following formula by step C:

$y_i=x_i+\underset{j=1}{\overset{K}{\&Sigma;}}{\mathrm{\&alpha;}}_{ij}sign{\left(x_i\right)}^{b_{ij}}{s}_t{w}_{ij}$

Wherein, w _ij∈ P represents by encryption key K _wthe pseudo-random sequence of encryption, b _ij∈ B represents by algorithm control key K _athe algorithm control sequence produced, the number of times of K representative digit watermark embedment, x _i∈ X represents the conversion coefficient of initial carrier, y _i∈ Y represents the conversion coefficient containing watermark carrier, α _ijthe embedment strength of ∈ α representative digit watermark, s _t∈ S represents copyright information.

2. the mixing additivity repeatedly watermark embedding method based on cloud environment according to claim 1, is characterized in that: the transform method in described steps A is discrete small wave converting method.

3., based on a mixing additivity repeatedly watermark decoding method for cloud environment, it is characterized in that, comprise the steps:

Step 1 receives the image of the utilization described in claim 1 or 2 based on the mixing additivity repeatedly watermark embedding method embed watermark of cloud environment;

The transform method that step 2 adopts conversion coefficient to meet generalized Gaussian distribution converts image, and described transform method is identical with the transform method adopted in watermark embedding method;

Step 3 adopts following formula to be watermark decode:

$\mathrm{\&Lambda;}\left(y\right)=\underset{i=1}{\overset{L}{\&Sigma;}}\underset{j=1}{\overset{K}{\&Sigma;}}{c}_i|y_i{|}^{(c_i-1)}{\mathrm{\&beta;}}^{c_i}{\mathrm{\&alpha;}}_{ij}sign{\left(y_i\right)}^{(b_{ij}+1)}{w}_{ij};$

Wherein, l is the spread spectrum dimension of copyright information, c _ibe the form parameter of generalized Gaussian distribution, σ is the standard variance of generalized Gaussian distribution function, and Γ (x) is gamma function;

In step 4 step 3, formula is decoded as following formula:

$s_t=\left\{\begin{array}{c}1,\mathrm{\&Lambda;}\left(y\right)>0\\ 0,\mathrm{\&Lambda;}\left(y\right)<0\end{array}\right..$

4. the mixing additivity repeatedly watermark decoding method based on cloud environment according to claim 3, is characterized in that: described transform method is discrete small wave converting method.