CN103700059A - Cloud storage image data ownership verifying method based on multifunction digital watermark - Google Patents

Abstract

The invention discloses a cloud storage image data ownership verifying method based on a multifunctional digital watermark. The method comprises the following steps that A, a data owner embeds a multifunction digital watermark into image data; B, the data owner transmits the image data embedded with the watermark to a cloud server so as to store the image data; C, the data owner verifies the image data stored in the cloud server by virtue of detecting the watermark embedded into the image data. D, if detecting that the fragile/semi-fragile watermark is in good condition, indicating that the data integrity is protected; if detecting that data content is damaged, repairing relevant information by virtue of the content restorable watermark; if requiring the data owner to provide the copyright and a user tracing function, verifying by virtue of detecting a Robust watermark. According to the method, the multifunctional watermark is adopted for performing data verification, so that an effect of achieving multiple purposes by use of one technology is achieved, and the method is beneficial to the deployment and implementation of a cloud storage safety system.

Description

The cloud storing image data property held method of proof based on multifunction digital watermark

Technical field

The invention belongs to digital watermark technology field, the especially a kind of cloud storage data property held method of proof based on multifunction digital watermark.

Background technology

2007, on ACM Computers and Communication security conference (CCS ' 07), the people such as Ateniese have proposed data existence proof (PDP under cloud environment, ProvableDataPossession) concept, based on rsa cryptosystem system, (RSA is conventional cipher mechanism in employing, the conventional cipher mechanism of information security field) homomorphism identifying algorithm, the public audit technology that a kind of data exist has been proposed.But at this algorithm, realize in the process of audit, same user data block, through repeatedly verification, can solve out by linear combination equation, thereby may cause the leakage of user data.Ateniese and Curtmola etc. had carried out some improvement for their definition and the defect of scheme afterwards.After this data storage method of proof starts towards future development with better function, emerge many achievements in research: from only supporting static store data to develop into, support to develop into dynamic memory data and support third party's public audit from a supported data owner individual audit.

The existing method addressing these problems is all to utilize the cryptographic techniques such as hash function, encryption and digital signature, and the information that can prove data owner's rights and interests is attached to data subject storage and propagates as a mark (Tag).The greatest problem of doing like this has two; one is the potential safety hazards such as data existence separated with mark is forged; another is that what need to use respectively during for data proof of possession, data ownership proof and copyright protection is different mark and diverse ways, is unfavorable for that system disposes and implement.

Digital watermarking can be divided into fragile watermark, semi-fragile watermarking and robust watermarking according to the characteristic of watermark.Fragile watermark is very responsive to the change of carrier, can not stand any change and processing, even if the minor alteration of carrier also should be detected.But often under many circumstances, carrier more or less can be subject to some and process, and has therefore proposed semi-fragile watermarking, and fragile watermark and semi-fragile watermarking are mainly used in authentication, such as distorting of carrier pointed out and integrity detection.Robust watermarking is mainly used in the copyright protection of digital product and follows the trail of, and it requires the watermark that embeds carrier can stand the attack of various operations, and can be from destroyed extracting containing watermark carrier.

Summary of the invention

Technical matters to be solved by this invention is to overcome the deficiencies in the prior art, designs a kind of cloud storing image data property held method of proof based on digital watermarking.

The present invention is for solving the problems of the technologies described above specifically by the following technical solutions:

The present invention proposes a kind of cloud storing image data property held method of proof based on multifunction digital watermark, comprises the following steps:

A. data owner is in multifunction digital watermark embedded images data, and described multifunction digital watermark comprises that fragility/semi-fragile watermarking, content can recover two or more the watermark in watermark, robust watermarking;

B. data owner sends the view data of embed watermark to Cloud Server and stores;

C. data verification person, by detecting the watermark in embedded images data, verifies the view data of Cloud Server storage;

If D. detected, find that fragility/semi-fragile watermarking is intact, data integrity protected is described; If detected, find that data content is damaged, by content, can recover watermark relevant information is repaired; If need to provide copyright and user tracking function to data owner, by detecting robust watermarking, verify.

Further, the cloud storing image data property the held method of proof based on multifunction digital watermark of the present invention, data owner will comprise the following steps in multifunction digital watermark embedded images data described in steps A:

A1. first embed robust watermarking, specific as follows:

101, the original image that is M * M by size is divided into the sub-block that the size of non-overlapping copies is m * m; M, m are natural number;

102, each sub-block is carried out to svd computing, take out the maximum singular value of each sub-block, be designated as S _i, the sequence number that i is sub-block, i=1,2 ..., (M/m) ²;

103, the average of calculating all sub-block maximum singular values, is designated as S _av,

$S_{\mathrm{av}}=\frac{S_1+S_2+...+S_{{(M/m)}^2}}{{(M/m)}^2};$

104, by contrast S _iand S _avbetween numerical values recited produce original watermark sequence W, if S _i>S _av, W _i=1, otherwise W _i=0; Original watermark sequence W is embedded in all sub-blocks, complete the embedding of robust watermarking;

A2. secondly embed fragility/semi-fragile watermarking, realize embedding content simultaneously and can recover watermark, realize the dual-use function being integrated for distorting detection and recovery information set; Specific as follows:

201, by embedding size after robust watermarking, be divided into the sub-block that the size of non-overlapping copies is m * m for the image of M * M;

202, each sub-block is carried out to discrete cosine transform, obtain piece matrix of coefficients C _i,j, i, j represents respectively this sub-block coordinate position in partitioned matrix, to each piece matrix of coefficients C _i,jwith Joint Photographic Experts Group quantization table Q, quantize to obtain quantizing rear matrix of coefficients QC _i,j, QC _i,jcomprise discrete cosine transform direct current and low frequency coefficient after quantification, reflected the main contents of image; Matrix of coefficients QC after this is quantized _i,jbe embedded into not quantize block matrix of coefficients C _i,jfrequency domain in, complete the embedding of fragility/semi-fragile watermarking;

203, establishing current block is I _i,j, its successor block is I _{i ', j '}, each piece in image has unique separately forerunner and successor block, forms a circular linked list, the mapping of piece position is shone upon by diagonally opposing corner, make to distort continuously when becoming piece cutting meeting with, the watermark information being kept in successor block is intact, makes to recover distorting piece;

Choose current block and successor block, calculate its relation vector R=QC _i,j-QC _{i ', j '}, then this is related to vector is embedded into not quantize block matrix of coefficients C _i,jfrequency domain in; Complete embedding content and can recover watermark;

By above-mentioned A1 and A2 step, completing multifunctional watermark is embedded in original digital image data.

Further, the cloud storing image data property the held method of proof based on multifunction digital watermark of the present invention, for fragility/semi-fragile watermarking, proves that the method for data integrity is:

If I _i,j' be current image block to be detected, its successor block is I _{i ', j '}', C _i,j' be piece I _i,j' the matrix of coefficients of not quantized-dct, QC _i,j' and QC _{i ', j '}' being respectively the content vector of corresponding current image block to be detected, successor block, the error that is related between two is:

$\mathrm{\δ}(I_{i,j}^{\text{'}},I_{i\text{'},j\text{'}}^{\text{'}})=\underset{k=1}{\overset{m}{\mathrm{\Σ}}}|R_{(i\text{'},j\text{'})}^{\text{'}}-R_{(i\text{'},j\text{'})}^{\text{'}}|;$

R ' _{(i, j)}, R ' _{(i ', j ')}be respectively the relation vector of current image block to be detected, successor block;

If current block I _i,j' be tampered or malicious operation, compose JM (i, j)=0, JM judges matrix, if be not tampered or malicious operation, composes JM (i, j)=1, and obtains thus the integrated authentication function of view data content.

Further, the cloud storing image data property held method of proof based on multifunction digital watermark of the present invention, when the content of view data is subject to distorting, by content, can recovers the method that watermark repairs relevant information and be: by the relation vector R ' being stored in successor block, carry out extensive restored data: I _i,j' for being distorted piece or uncertain, its successor block is I _{i ', j '}', calculate R '+QC _{i ', j '}'=QC _i,j'.

Further, the cloud storing image data property the held method of proof based on multifunction digital watermark of the present invention, for the detection method of the robust watermarking embedding is:

By image or under fire image be divided into the sub-block that the size of non-overlapping copies is m * m, each sub-block is carried out to svd computing, take out the maximum singular value of each sub-block, be designated as S _i';

The average of calculating all sub-block maximum singular values, is designated as S _av',

$S_{\mathrm{av}}^{\text{'}}=\frac{S_1^{\text{'}}+S_2^{\text{'}}+...+S_{{(M/m)}^2}^{\text{'}}}{{(M/m)}^2};$

By contrast S _i' and S _av' the watermark sequence W ' of numerical values recited after producing under fire, if S _i' >S _av', W _i'=1, otherwise W _i'=0;

The similarity of between zero watermark sequence W ' of calculating original zero watermark sequence W and under fire extracting afterwards, definition similarity is

according to predefined threshold value th, adjudicate copyright ownership: if s>=th adjudicates so view data holder and has legal copyright; Otherwise judgement does not have legal copyright.

The present invention adopts above technical scheme, compared with prior art has following beneficial effect:

Cloud storing image data the holding property method of proof of utilization of the present invention based on multifunction digital watermark; the function of data content Integrity Verification not only can be provided; and can recover damaged data content; and can provide to data content the functions such as copyright protection by robust watermarking; realize the effect that adopts a kind of technology to reach plurality of target, be conducive to deployment and the enforcement of cloud storage security system.

Accompanying drawing explanation

Fig. 1 is the cloud storing image data property the held method of proof schematic diagram based on multifunction digital watermark.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail:

Multifunctional watermark proposed by the invention refers to and in numerical information, embeds watermark of different nature, reach different objects, for example in piece image, embed a visible watermark and an invisible watermark, the former is for copyright notice simultaneously, and the latter is for copyright protection; And for example in piece image, embed a fragile watermark and a robust watermarking, the former can be for distorting prompting simultaneously, and the latter can be for copyright protection.

As shown in Figure 1; the present invention proposes the cloud storing image data property the held method of proof based on multifunction digital watermark: adopt fragile watermark/semi-fragile watermarking that the integrated authentication function of data content is provided; adopting content can recover watermark can restore funcitons to what data content was provided when damaging appears in data content, and employing robust watermarking provides the copyright protection function of data.Specifically comprise the following steps:

A. data owner is in multifunction digital watermark embedded images data, and described multifunction digital watermark comprises that fragile watermark/semi-fragile watermarking, content can recover watermark, robust watermarking;

B. data owner sends the view data of embed watermark to Cloud Server and stores;

C. data verification person, by detecting the watermark in embedded images data, verifies the view data of Cloud Server storage;

If D. detected, find that fragility/semi-fragile watermarking is intact, data integrity protected is described; If detected, find that data content is damaged, by content, can recover watermark relevant information is repaired; If need to provide copyright and user tracking function to data owner, by detecting robust watermarking, verify.

The present embodiment be take multifunction digital watermark and is used object to be example as image, specific as follows:

Steps A, data owner are by multifunction digital watermark embedding data, and fragile watermark, because its fragility easily goes to pot, so embedding is sequentially to embed fragile watermark after first embedding robust watermarking, specifically comprises the following steps:

A1. first embed robust watermarking:

The original image that is M * M by size is divided into the sub-block that the size of non-overlapping copies is m * m;

Each sub-block is carried out svd computing, takes out the maximum singular value of each sub-block, is designated as S _i, the sequence number that i is sub-block, i=1,2 ..., (M/m) ²;

The average of calculating all sub-block maximum singular values, is designated as S _av,

$S_{\mathrm{av}}=\frac{S_1+S_2+...+S_{{(M/m)}^2}}{{(M/m)}^2};$

Original watermark sequence W is by contrast S _iand S _avbetween numerical values recited produce, if S _i>S _av, W _i=1, otherwise W _i=0; Original watermark sequence W is embedded in all sub-blocks, complete the embedding of robust watermarking.

A2. secondly embed fragile watermark, by the feature meeting the demands is carried out enable after coding spread spectrum and main contents between directly form a kind of original function and the two-way like this mapping relations one to one of inverse function, realized the dual-use function being integrated for distorting the information set that detects and recover:

The original image that is M * M by size is divided into the sub-block that the size of non-overlapping copies is m * m;

Again each piece is carried out to discrete cosine transform, obtain piece matrix of coefficients C _i,j, i, j represents this piece coordinate position in partitioned matrix, to each piece C _i,jwith Joint Photographic Experts Group quantization table Q, quantize to obtain quantizing rear matrix of coefficients QC _i,j, QC _i,jcomprise discrete cosine transform direct current and low frequency coefficient after quantification, reflected the main contents of image;

Current block is I _i,j, its successor block is I _{i ', j '}, each piece in image has unique separately forerunner and successor block, forms a circular linked list, the mapping of piece position is shone upon by diagonally opposing corner, make to distort continuously when becoming piece cutting meeting with, the watermark information being kept in successor block is intact as far as possible, is convenient to these to distort the recovery of piece;

Choose current block and successor block, calculate it and be related to R=QC _i,j-QC _{i ', j '}, then this relation is embedded into not quantize block matrix of coefficients C _i,jfrequency domain in, realize to embed content and can recover watermark:

By above-mentioned steps, realizing multifunctional watermark is embedded in original digital image data.

Further, when the multifunctional watermark of embedding is fragile watermark, prove that the method for data integrity is:

I _i,j' be current image block to be detected, its successor block is I _{i ', j '}', C _i,j' be piece I _i,j' the matrix of coefficients of not quantized-dct, QC _i,j' and QC _{i ', j '}' be the content vector of corresponding blocks, the error that is related between two is

$\mathrm{\δ}(I_{i,j}^{\text{'}},I_{i\text{'},j\text{'}}^{\text{'}})=\underset{k=1}{\overset{m}{\mathrm{\Σ}}}|R_{(i\text{'},j\text{'})}^{\text{'}}-R_{(i\text{'},j\text{'})}^{\text{'}}|;$

If current block I _i,j' be tampered or malicious operation, compose JM (i, j)=0, JM judges matrix, if be not tampered or malicious operation, composes JM (i, j)=1, and obtains thus the integrated authentication function of view data content.

Further, when the content of view data is subject to distorting, by content, can recovers the method that watermark repairs relevant information and be:

In previous step, the content of view data is distorted, and by the relation vector being stored in successor block, carrys out extensive restored data: I _i,j' for being distorted piece or uncertain, its successor block is I _{i ', j '}', calculate R '+QC _{i ', j '}'=QC _i,j'.

Detection method when further, the multifunctional watermark of embedding is robust watermarking is:

By image or under fire image be divided into the sub-block that the size of non-overlapping copies is m * m, each sub-block is carried out svd computing, takes out the maximum singular value of each sub-block, is designated as S _i';

The average of calculating all sub-block maximum singular values, is designated as S _av',

$S_{\mathrm{av}}^{\text{'}}=\frac{S_1^{\text{'}}+S_2^{\text{'}}+...+S_{{(M/m)}^2}^{\text{'}}}{{(M/m)}^2};$

Watermark sequence W ' is under fire by contrast S _i' and S _av' numerical values recited produce, if S _i' >S _av',

W _i'=1, otherwise W _i'=0;

The similarity of between zero watermark sequence W ' of calculating original zero watermark sequence W and under fire extracting afterwards, definition similarity is

according to predefined threshold value, adjudicate copyright ownership: if s>=th, th is threshold value, adjudicates so view data holder and has legal copyright; Otherwise judgement does not have legal copyright.This threshold value th arranges according to the General Requirement of image, those skilled in the art all should know, such as can reference: the < < of < < Journal of Computer Research and Development > > interim publication of calendar year 2001 05 is Research on threshold selection > > mono-literary composition apart from tolerance based on image difference.

Although the present invention describes by specific embodiment, it will be appreciated by those skilled in the art that, in the situation that not departing from minute invention scope, can also carry out various conversion and be equal to alternative the present invention.In addition, for particular condition, can make various modifications to the present invention, and not depart from the scope of the present invention.Therefore, the present invention is not limited to disclosed specific embodiment, and should comprise the whole embodiments that fall within the scope of the claims in the present invention.

Claims (5)

1. the cloud storing image data property the held method of proof based on multifunction digital watermark, is characterized in that: comprise the following steps:

A. data owner is in multifunction digital watermark embedded images data, and described multifunction digital watermark comprises that fragility/semi-fragile watermarking, content can recover two or more the watermark in watermark, robust watermarking;

B. data owner sends the view data of embed watermark to Cloud Server and stores;

C. data verification person, by detecting the watermark in embedded images data, verifies the view data of Cloud Server storage;

If D. detected, find that fragility/semi-fragile watermarking is intact, data integrity protected is described; If detected, find that data content is damaged, by content, can recover watermark relevant information is repaired; If need to provide copyright and user tracking function to data owner, by detecting robust watermarking, verify.

2. the cloud storing image data property the held method of proof based on multifunction digital watermark according to claim 1, is characterized in that: described in steps A, data owner will comprise the following steps in multifunction digital watermark embedded images data:

A1. first embed robust watermarking, specific as follows:

101, the original image that is M * M by size is divided into the sub-block that the size of non-overlapping copies is m * m; M, m are natural number;

102, each sub-block is carried out to svd computing, take out the maximum singular value of each sub-block, be designated as S _i, the sequence number that i is sub-block, i=1,2 ..., (M/m) ²;

103, the average of calculating all sub-block maximum singular values, is designated as S _av,

$S_{\mathrm{av}}=\frac{S_1+S_2+...{+S}_{{(M/m)}^2}}{{(M/m)}^2};$

104, by contrast S _iand S _avbetween numerical values recited produce original watermark sequence W, if S _i>S _av, W _i=1, otherwise W _i=0; Original watermark sequence W is embedded in all sub-blocks, complete the embedding of robust watermarking;

A2. secondly embed fragility/semi-fragile watermarking, realize embedding content simultaneously and can recover watermark, realize the dual-use function being integrated for distorting detection and recovery information set; Specific as follows:

201, by embedding size after robust watermarking, be divided into the sub-block that the size of non-overlapping copies is m * m for the image of M * M;

202, each sub-block is carried out to discrete cosine transform, obtain piece matrix of coefficients C _i,j, i, j represents respectively this sub-block coordinate position in partitioned matrix, to each piece matrix of coefficients C _i,jwith Joint Photographic Experts Group quantization table Q, quantize to obtain quantizing rear matrix of coefficients QC _i,j, QC _i,jcomprise discrete cosine transform direct current and low frequency coefficient after quantification, reflected the main contents of image; Matrix of coefficients QC after this is quantized _i,jbe embedded into not quantize block matrix of coefficients C _i,jfrequency domain in, complete the embedding of fragility/semi-fragile watermarking;

203, establishing current block is I _i,j, its successor block is I _{i ', j '}, each piece in image has unique separately forerunner and successor block, forms a circular linked list, the mapping of piece position is shone upon by diagonally opposing corner, make to distort continuously when becoming piece cutting meeting with, the watermark information being kept in successor block is intact, makes to recover distorting piece;

Choose current block and successor block, calculate its relation vector R=QC _i,j-QC _{i ', j '}, then this is related to vector is embedded into not quantize block matrix of coefficients C _i,jfrequency domain in, complete embedding content and can recover watermark;

By above-mentioned A1 and A2 step, completing multifunctional watermark is embedded in original digital image data.

3. the cloud storing image data property the held method of proof based on multifunction digital watermark according to claim 2, is characterized in that: for fragility/semi-fragile watermarking, prove that the method for data integrity is:

If I _i,j' be current image block to be detected, its successor block is I _{i ', j '}', C _i,j' be piece I _i,j' the matrix of coefficients of not quantized-dct, QC _i,j' and QC _{i ', j '}' being respectively the content vector of corresponding current image block to be detected, successor block, the error that is related between two is:

$\mathrm{\&delta;}(I_{i,j}^{\text{'}},I_{i\text{'},j\text{'}}^{\text{'}})=\underset{k=1}{\overset{m}{\mathrm{\&Sigma;}}}|R_{(i\text{'},j\text{'})}^{\text{'}}-R_{(i\text{'},j\text{'})}^{\text{'}}|;$

R ' _{(i, j)}, R ' _{(i ', j ')}be respectively the relation vector of current image block to be detected, successor block;

If current block I _i,j' be tampered or malicious operation, compose JM (i, j)=0, JM judges matrix, if be not tampered or malicious operation, composes JM (i, j)=1, and obtains thus the integrated authentication function of view data content.

4. the cloud storing image data property the held method of proof based on multifunction digital watermark according to claim 3, it is characterized in that: when the content of view data is subject to distorting, by content, can recovers the method that watermark repairs relevant information and be: by the relation vector R ' being stored in successor block, carry out extensive restored data: I _i,j' for being distorted piece or uncertain, its successor block is I _{i ', j '}', calculate R '+QC _{i ', j '}'=QC _i,j'.

5. the cloud storing image data property the held method of proof based on multifunction digital watermark according to claim 2, is characterized in that: the detection method for the robust watermarking embedding is:

By image or under fire image be divided into the sub-block that the size of non-overlapping copies is m * m, each sub-block is carried out to svd computing, take out the maximum singular value of each sub-block, be designated as S _i';

The average of calculating all sub-block maximum singular values, is designated as S _av',

$S_{\mathrm{av}}^{\text{'}}=\frac{S_1^{\text{'}}+S_2^{\text{'}}+...+S_{{(M/m)}^2}^{\text{'}}}{{(M/m)}^2};$

By contrast S _i' and S _av' the watermark sequence W ' of numerical values recited after producing under fire, if S _i' >S _av', W _i'=1,

Otherwise W _i'=0;

The similarity of between zero watermark sequence W ' of calculating original zero watermark sequence W and under fire extracting afterwards, definition similarity is

according to predefined threshold value th, adjudicate copyright ownership: if s>=th adjudicates so view data holder and has legal copyright; Otherwise judgement does not have legal copyright.

Images