CN103903217A - Vector map integrity authentication method based on vertex insertion - Google Patents

Abstract

The invention belongs to the field of geographic information science and information hiding, and particularly relates to a vector map integrity authentication method based on vertex insertion. The method comprises the steps of dividing a vector map into multiple areas, conducting block sorting on the vector map, recording the block type of the vector map, generating an authentication watermark, embedding the authentication watermark, and conducting watermark authentication and original data recovery. According to the method, the vector map is divided into multiple areas, corresponding authentication information is embedded into each area with the vertex insertion method, and in this way, in the authentication phase, not only can integrity authentication be achieved, tampered areas can also be positioned accurately, and the frequency of data retransmission caused by the failure in detecting tampered data accurately is effectively reduced; the false alarm rate is zero, the false dismissal rate is (1/2)L, and tampering detection can be conducted effectively.

Description

A kind of map vector completeness certification method inserting based on summit

Technical field

The invention belongs to Geographical Information Sciences, Information hiding field, be specifically related to a kind of map vector completeness certification method inserting based on summit.

Background technology

Along with the fast development of infotech and surveying and mapping technology, two-dimension vector map data have become the essential Support Resources in aspect such as Geographic Information System, intelligent transport system, digitalized city and digitizing national defense construction.The geography information of two-dimension vector map data description is full and accurate accurately, has huge economic worth and strategic importance.And by network and geographic information processing instrument, these data with huge economic value are easy to by bootlegging, distort and propagate.The map vector data of distorting, causes damage not only can to the precision of map vector, more can make the geography information producer, publisher and user sustain a great loss.When geographic information services is provided, the authenticity and integrity that how to ensure map vector data is current problem in the urgent need to address.

Digital signature technology in cryptography can be realized integrated authentication and the true and false of map vector and differentiate.But this technology can not positioning tampering position, once find that data change, no matter the data of distorting are desired data or non-required data, capital is thought that data are tampered and can not be used, need to again obtain data, increased time and the expense of data acquisition, unnecessary delay is caused in the application scenario that need to obtain in time data to some.And afterbody or head that the digital signature having is attached to copyright transmit together with copyright, when copyright is after format conversion and other operations, the digital signature of himself carrying will be lost, and causes authentication to be lost efficacy.For making up the defect of digital signature technology, Fragile Watermarking Technique arises at the historic moment as a kind of effective means of integrated authentication, becomes a focus of geography information digital product integrated authentication area research in recent years.

In Fragile Watermarking Technique, data receiver is divided into copyright after some parts, for every partial data generates corresponding authentication information and is embedded in corresponding data.The consistance of the authentication information that data receiver extracts in every partial data by judgement and the authentication information of generation, detects and positioning tampering data.Utilize the characteristic of Fragile Watermarking Technique positioning tampering, people can judge that altered data is the current data that will need or non-required data, thereby avoid factor data to retransmit the resource and the waste of time that cause.Because authentication information is hidden in copyright, with works interwoveness, together transmit, Fragile Watermarking Technique makes more hidden, the safety of authentication information transmission simultaneously.

In recent years, Fragile Watermarking Technique is at image, video, and considerable achievement in research has been obtained in audio frequency and text data field.The research of vector map watermark technology is progressively tending towards to ripe, but aspect map vector Fragile Watermarking Technique, the achievement that people obtain is also fewer.Use for reference the reversible authentication method for image integrity authentication that the people such as J.Fridrich propose, first the people such as Shao Chengyong proposed a kind of reversible Fragile Watermark Algorithm for two-dimension vector map integrated authentication in 2005.This algorithm is divided into map vector summit after different groups, generates corresponding authentication information and utilizes the people's such as Fridrich reversible authentication method to realize the embedding of watermark for every group.The method can detect that the multiple of map vector distort operation, attack but can not resist vector quantization, and when map vector increased summit/pel, when deleting summit/pel and operating, the tampering location ability of the method is strong not.Utilize equally the people's such as Fridrich reversible authentication method, 2009, the people such as Zheng in conjunction with the thought of piecemeal proposed can positioning tampering piece map vector reversible Fragile Watermark Algorithm.This method can tamper detection region, but increase, delete after attack when map vector suffers summit, tampering location ability is still poor, and if embedding parameter select improper, the method can not guarantee all map vectors can both correctly extract watermark information.Subsequently, the people such as Zheng proposes the reversible Fragile Watermark Algorithm of map vector of positioning tampering figure tuple in conjunction with the thought of pel grouping.The method is faced with the problem that map vector suffers that summit/pel increases, deletes tampering location scarce capacity after attacking equally.For obtaining good altered data positioning precision, Wang and Men have proposed the reversible vulnerable watermark method of map vector based on figure meta-tag.The method is positioning tampering figure tuple accurately, but can't be applied to a pel.

In addition, Zhang and Gao have proposed a kind of two-dimension vector graphics Semi-fragile watermarking algorithm based on dct transform.The method is to rotation, convergent-divergent, translation robust, but the embedding of watermark may affect the summit sequence situation of authentication phase, and then affects its grouping situation, causes watermark information correctly to extract, thereby cannot complete integrated authentication.The people such as Peng Fei have proposed a kind of semi-fragile watermarking method of two-dimentional CAD engineering drawing based on log-polar transform.The method is divided into groups summit, will be mapped to log-polar system for the summit of embed watermark, and the method for utilizing position to replace embeds watermark information in log-polar.For improving its tampering location ability, algorithm makes marks to guarantee that authentication phase can correctly divide into groups in the attribute information of the Article 1 line of each grouping.This scheme is to rotation, convergent-divergent, translation robust, but in the time that a certain group of data are deleted, tampering location ability is still not high.

In sum, although people have proposed some at present for map vector vulnerable watermark method, attempt to solve in verify data integrality the problem of positioning tampering, these methods Shortcomings also aspect accurate positioning tampering.

Summary of the invention

The object of the present invention is to provide accurately positioning tampering region of one, effectively reduce the map vector completeness certification method inserting based on summit because of the data re-transmission number of times that accurately tamper detection data cause.

The object of the present invention is achieved like this:

(1) divide map vector region;

Map vector pel is divided into the piece of non-overlapping copies, line number and the columns of the piece that map vector is divided are designated as N _rand N _w, the sum of piece is designated as N _b, N _b=N _r× N _w, i, i=1,2 ..., N _bindividual map vector piece is designated as B _i, comprise piece B _ileft upper apex and the summit, bottom right of rectangle of regional extent be designated as respectively

with

with

represent respectively

x coordinate and y coordinate, with

represent respectively

x coordinate and y coordinate;

(2) map vector block sort;

All pieces are divided into two classes, and normal piece and empty piece, by piece B _isummit number be designated as

if

piece B _ifor normal piece; Otherwise, piece B _ifor empty piece;

(3) record map vector block type;

Generation comprises N _bthe sequence F of individual element, the type of each in recording step (2),

F＝{f _i|f _i∈{0,1},i＝1,...,N _B}

Wherein, f _i=0 represents that i piece is a normal piece, f _i=1 represents that i piece is an empty piece;

(4) generate authenticating water-mark;

Generate the authenticating water-mark of each normal piece in step (2), by piece B _iwatermark information be designated as H _i,

H _i＝{h _i,j∈{0,1},j∈[0,L-1]}

Wherein, L represents the number of bit in Hi, h _i,j(0≤j≤L – 1) represents H _iin j bit;

(5) embed authenticating water-mark;

The authenticating water-mark generating in step (4) is embedded in normal piece to embed watermark in normal piece

(5.1) according to map vector piece B _iborder, calculate B _icenter with

represent respectively center B _c,ix coordinate and y coordinate;

(5.2) generate one with B _c,icentered by, the round CB that r is radius _i(B _c,i, r), will be at circle CB _i(B _c,i, on circumference r), to insert and contain watermark summit with Hidden Authentication watermark, the value of radius r is:

$(B_{i,\max }^x-B_{i,\min }^x,B_{i,\max }^y-B_{i,\min }^y)$

(5.3) authenticating water-mark Hi is converted to the watermark sequence W that will embed _i={ W _i,j| j ∈ [0, N _a– 1] }, W _i,jrepresent sequence W _iin j element, N _arepresent sequence W _imiddle element number;

(5.4) according to key K ^d, generate double-precision floating points sequence A _i={ A _i,j| j ∈ [0, N _a– 1], (0≤A _i,j<180) }, A _i,jrepresent sequence A _ij element, sequence A _ibe used for embed watermark sequence W _iangle sequence;

(5.5) for each element W of sequence Wi _i,j(j ∈ [0, N _a– 1]), be embedded into j angle A in sequence A i _i,jmagnitude portion, be designated as A by what obtain containing watermark angle _i,j';

(5.6) according to containing watermark angle A _i,j', calculate at circle CB _icircumference on containing watermark summit

position,

$\left\{\begin{array}{c}{r}_j^a=A_{i,j}\&prime;\&times;(\mathrm{\&pi;}/180)\\ v_{i,j}^x=B_{c,j}^x+r\&times;\cos \left(r_j^a\right)\\ v_{i,j}^y=B_{c,i}^y+r\&times;\sin \left(r_j^a\right)\end{array}\right.$

Wherein,

with

represent respectively v _i,jx coordinate and y coordinate, be designated as V by what calculate containing watermark vertex set _i={ v _i,j| j ∈ [0, N _a– 1] };

(5.7) by V _iin be inserted in map vector containing watermark summit, obtain containing watermark map vector;

(6) watermark authentication and raw data are recovered;

The piece of non-overlapping copies will be divided into containing the pel of watermark map vector; According to the type of each of sequence F identification in step (3);

For empty piece, in piece, contain summit, suffer to distort depending on it; Otherwise, think that this piece is by authentication, for normal piece:

(6.1) according to computing block B in step (5) _i' center

and generate with B _c,i' centered by, the circle that r' is radius

with

represent respectively center B _c,i' x coordinate and y coordinate;

(6.2) search CB _i' all summits on circumference, by CB _i' the set on all summits is designated as on circumference $V_i^c=$ $\left\{v_{i,j}^c(v_{i,j}^{c,x},v_{i,j}^{c,y})\right|j\&Element;[0,N_c-1]\left)\right\},v_{i,j}^c$ Table CB _i' j summit on circumference, $v_{i,j}^{c,x}$ With $v_{i,j}^{c,y}$ Represent respectively summit $v_{i,j}^c$ X coordinate and y coordinate, N _crepresent

the summit number comprising;

(6.3) obtain all possible watermark vertex set that contains, the sequence containing watermark vertex set is designated as $V_i^p=\left\{V_{i,j}^p\right|j\&Element;[0,$ $N_p-1\left]\right\},V_{i,j}^p=\left\{v_{i,j,k}^p(v_{i,j,k}^{p,x},v_{i,j,k}^{p,y})\right|k\&Element;[0,N_A-1]\}$ Represent one possible containing watermark vertex set, by from

in choose N _aindividual different summit obtains,

express possibility containing watermark vertex set in k summit,

with

represent respectively summit

x coordinate and y coordinate,

express possibility containing the number of watermark vertex set;

(6.4) for

in eachly may contain watermark vertex set

(6.4.1) utilize the watermark generation method of describing in step (4) to generate the watermark information H of Bi'' _i'={ h _i,j' | h _i,j' ∈ { 0,1}, j ∈ [0, L – 1] }, B _i' ' represent not comprise the piece B on middle summit _i';

(6.4.2) generate one containing watermark vertex set $V_{i,j}\&prime;=\{v_{i,j,k}\&prime;(v_{i,j,k}^x\&prime;,v_{i,j,k}^y\&prime;)|k\&Element;[0,N_A-1]\},v_{i,j,k}\&prime;$ Represent V _i,j' k summit,

with

represent respectively vertex v _{i, j, k}' x coordinate and y coordinate;

If (6.4.3)

piece B _i' comprise it accordingly containing watermark summit, piece B _i' by integrated authentication, delete

in summit with recover raw data, piece B _i' verification process leave it at that; Otherwise, repeating step (6.4) until

all set are all completed;

(6.5) if middle neither one may be piece B containing watermark vertex set _i' containing watermark vertex set, think piece B _i' suffered to distort.

Beneficial effect of the present invention is:

Map vector is divided into some regions by the present invention, the method of utilizing summit to insert embeds corresponding authentication information in each region, in authentication phase, not only can realize integrated authentication, and accurate positioning tampering region, effectively reduce the data re-transmission number of times because accurately tamper detection data cause; The present invention is carrying out after integrated authentication, and what the deletion watermark embedding stage inserted contains watermark summit, and precise restoration map vector raw data can meet the demand that user accurately uses map vector data; The alert rate of mistake of the present invention (being about to there is no the Data Detection of distorting is the probability of distorting) is zero, and false dismissed rate (Data Detection that is about to distort is the probability of distorting) is (1/2) ^l, effectively tamper detection.

Accompanying drawing explanation

Fig. 1 is the map vector completeness certification method process flow diagram inserting based on summit;

Fig. 2 is a piece and the example that is divided into the line chart unit in this piece;

Fig. 3 is IEEE-754 double-precision floating point form;

Fig. 4 is the map vector before embed watermark;

Fig. 5 is the map vector after embed watermark;

Fig. 6 be distort containing watermark map vector;

Fig. 7 is the map vector of positioning tampering.

Embodiment

Below in conjunction with accompanying drawing, 1-7 is described further the present invention.

The present invention proposes a kind of map vector completeness certification method inserting based on summit, the method is divided to map vector pel in different regions on the one hand, generate the corresponding authentication information in each region in conjunction with hashing algorithm, authentication information is embedded in angle sequence, and according to calculating the position containing watermark summit containing watermark angle sequence, the method of utilizing summit to insert realizes authentication information hiding in map vector data, can effectively solve the problem in accurate positioning tampering region; This algorithm is extracting after authentication information on the other hand, deletes the watermark summit that contains of inserting and can't harm reduction map vector raw data, can effectively guarantee the accurate use of map vector data.Experimental result shows the accurate positioning tampering of this scheme position, is a kind of practical algorithm for map vector integrated authentication, positioning tampering.

Map vector pel (some pel, line chart unit and face pel) is to be arranged and form according to specific order by a large amount of intensive summits, and map datum is exactly the 2 dimension coordinate sequences on these summits.Map vector Fragile Watermarking Technique is a kind of important means that solves map vector integrated authentication, positioning tampering problem.The map vector fragile watermark strategy of the current proposition of people can reach the target of verify data integrality and authenticity, but these strategies Shortcomings also aspect accurate positioning tampering.For the problems referred to above, the present invention proposes the map vector completeness certification method inserting based on summit, comprises the steps:

(1) divide map vector region;

In this step, map vector pel is divided into the piece of non-overlapping copies.The regional extent of a map vector piece can be considered as the region that a left upper apex by rectangle and summit, bottom right define.Line number and the columns of the piece that map vector is divided are designated as N _rand N _w, the sum of piece is designated as N _b(N _b=N _r× N _w), i (i=1,2 ..., N _b) individual map vector piece is designated as B _i, comprise piece B _ileft upper apex and the summit, bottom right of rectangle of regional extent be designated as respectively

with

with

represent respectively

x coordinate and y coordinate,

with

represent respectively

x coordinate and y coordinate.

(2) map vector block sort;

In this step, according to the number on summit in each region unit, all pieces are divided into two classes: normal piece and empty piece.By piece B _isummit number be designated as

if

piece B _iit is a normal piece; Otherwise, piece B _iit is an empty piece.The present invention is embed watermark in normal piece only.

(3) record map vector block type;

In this step, generate one and comprise N _bthe sequence F of individual element, this sequence is used for the type of each of recording step (2),

F＝{f _i|f _i∈{0,1},i＝1,...,N _B}

Wherein, f _i=0 represents that i piece is a normal piece, f _i=1 represents that i piece is an empty piece.

(4) generate authenticating water-mark;

In this step, utilize hashing algorithm, generate the authenticating water-mark of each normal piece in step (2).By piece B _iwatermark information be designated as H _i,

H _i＝{h _i,j∈{0,1},j∈[0,L-1]}

Wherein, L represents H _ithe number of middle bit, h _i,j(0≤j≤L – 1) represents j bit in Hi.

(5) embed authenticating water-mark;

In this step, the method for utilizing summit to insert, is embedded into the authenticating water-mark generating in step (4) in corresponding normal piece.In a normal piece, the concrete steps of embed watermark (are supposed piece B as follows _ibe a normal piece, the watermark that embed is H _i):

A. according to map vector piece B _iborder, calculate B _icenter

with

represent respectively center B _c,ix coordinate and y coordinate;

B. generate one with B _c,icentered by, the round CB that r is radius _i(B _c,i, r).The present invention will be at circle CB _i(B _c,i, on circumference r), insert containing watermark summit with Hidden Authentication watermark.For guaranteeing can not exceed piece B containing watermark summit _iborder, the value of radius r should meet the following conditions,

$(B_{i,\max }^x-B_{i,\min }^x,B_{i,\max }^y-B_{i,\min }^y)$

C. by authenticating water-mark H _iconvert the watermark sequence W that will embed to _i={ W _i,j| j ∈ [0, N _a– 1] }, W _i,jrepresent sequence W _iin j element, N _arepresent sequence W _imiddle element number;

D. in key K ^dparticipation under, generate a double-precision floating points sequence A _i={ A _i,j| j ∈ [0, N _a– 1], (0≤A _i,j<180) }.A _i,jrepresent sequence A _ij element, sequence A _ibe used for embed watermark sequence W _iangle sequence;

E. for sequence W _ieach element W _i,j(j ∈ [0, N _a– 1]), the method for utilizing position to replace is embedded into sequence A _iin j angle A _i,jmagnitude portion.Be designated as A by what obtain containing watermark angle _i,j';

F. according to containing watermark angle A _i,j', calculate at circle CB _icircumference on containing watermark summit

position,

$\left\{\begin{array}{c}{r}_j^a=A_{i,j}\&prime;\&times;(\mathrm{\&pi;}/180)\\ v_{i,j}^x=B_{c,j}^x+r\&times;\cos \left(r_j^a\right)\\ v_{i,j}^y=B_{c,i}^y+r\&times;\sin \left(r_j^a\right)\end{array}\right.$

Wherein,

with

represent respectively v _i,jx coordinate and y coordinate.Be designated as V by what calculate according to step e-f containing watermark vertex set _i={ v _i,j| j ∈ [0, N _a– 1] };

G. by V _iin be inserted in map vector containing watermark summit, obtain containing watermark map vector.

(6) watermark authentication and raw data are recovered;

In this step, the piece of non-overlapping copies will be divided into containing the pel of watermark map vector; Utilize sequence F in step (3) to identify the type of each; Utilize diverse ways to authenticate the integrality of different pieces.

For an empty piece, if contain summit in this piece, suffer to distort depending on it; Otherwise, think that this piece is by authentication.

For a normal piece, the concrete steps of its verification process are following (to be supposed containing watermark block B _i' be a normal piece):

A. according to the a-b computing block B in step (5) _i' center and generate one with B _c,i' centered by, the round CB that r' is radius _i' (B _c,i', r').Wherein,

with represent respectively center B _c,i' x coordinate and y coordinate;

B. search for CB _i' all summits on circumference.By CB _i' the set on all summits is designated as on circumference

table CB _i' j summit on circumference,

with

represent respectively summit

x coordinate and y coordinate, Nc represents

the summit number comprising;

C. obtain all possible containing watermark vertex set.The all possible sequence containing watermark vertex set is designated as $V_i^p=$ $\left\{V_{i,j}^p\right|j\&Element;[0,N_p-1]\},$ Wherein, $V_{i,j}^p=\left\{v_{i,j,k}^p(v_{i,j,k}^{p,x},v_{i,j,k}^{p,y})\right|k\&Element;[0,N_A-1]\}$ Represent one possible containing watermark vertex set, this set by from

in choose N _aindividual different summit obtains,

express possibility containing watermark vertex set

in k summit,

with represent respectively summit

x coordinate and y coordinate,

express possibility containing the number of watermark vertex set;

D. for

in eachly may contain watermark vertex set carry out following 3 steps:

P1. utilize the watermark generation method of describing in step (4) to generate B _i' ' watermark information

l – 1] }.Wherein, B _i' ' represent not comprise

the piece B on middle summit _i'.

P2. utilize c-f and the H of step (5) _i', generate one containing watermark vertex set

represent V _i,j' k summit,

with

represent respectively vertex v _{i, j, k}' x coordinate and y coordinate.

If p3.

piece B _i' comprise it accordingly containing watermark summit, piece B _i' by integrated authentication, delete

in summit with recover raw data, piece B _i' verification process leave it at that; Otherwise, repeating step d until

all set are all completed.

If e.

middle neither one may be piece B containing watermark vertex set _i' containing watermark vertex set, think piece B _i' suffered to distort.

Verify after the integrality of each map vector piece, shown all map vector pieces that are tampered.

The present invention proposes a kind of map vector completeness certification method based on inserting summit, the method is divided to map vector pel in different regions on the one hand, generate the corresponding authentication information in each region in conjunction with hashing algorithm, authentication information is embedded in angle sequence, according to calculating the position containing watermark summit containing watermark angle sequence, the method of utilizing summit to insert realizes authentication information hiding in map vector data, can effectively solve the problem in accurate positioning tampering region; This algorithm is extracting after authentication information on the other hand, deletes the watermark summit that contains of inserting and can't harm reduction map vector raw data, can effectively guarantee the accurate use of map vector data.Compared with other map vector completeness certification methods, the present invention has the following advantages:

1, map vector is divided into some regions by the present invention, the method of utilizing summit to insert embeds corresponding authentication information in each region, in authentication phase, not only can realize integrated authentication, and accurate positioning tampering region, effectively reduce the data re-transmission number of times because accurately tamper detection data cause;

2, the present invention is carrying out after integrated authentication, and what the deletion watermark embedding stage inserted contains watermark summit, and precise restoration map vector raw data can meet the demand that user accurately uses map vector data;

3, the alert rate of mistake of the present invention (being about to there is no the Data Detection of distorting is the probability of distorting) is zero, and false dismissed rate (Data Detection that is about to distort is the probability of distorting) is (1/2) ^l, effectively tamper detection.

The present invention proposes a kind of map vector completeness certification method based on inserting summit, the method is divided to map vector pel in different regions on the one hand, generate the corresponding authentication information in each region in conjunction with hashing algorithm, authentication information is embedded in angle sequence, according to calculating the position containing watermark summit containing watermark angle sequence, the method of utilizing summit to insert realizes authentication information hiding in map vector data, can effectively solve the problem in accurate positioning tampering region; This algorithm is extracting after authentication information on the other hand, deletes the watermark summit that contains of inserting and can't harm reduction map vector raw data, can effectively guarantee the accurate use of map vector data.Compared with other map vector completeness certification methods, the present invention has the following advantages:

1, map vector is divided into some regions by the present invention, the method of utilizing summit to insert embeds corresponding authentication information in each region, in authentication phase, not only can realize integrated authentication, and accurate positioning tampering region, effectively reduce the data re-transmission number of times because accurately tamper detection data cause;

2, the present invention is carrying out after integrated authentication, and what the deletion watermark embedding stage inserted contains watermark summit, and precise restoration map vector raw data can meet the demand that user accurately uses map vector data;

3, the alert rate of mistake of the present invention (being about to there is no the Data Detection of distorting is the probability of distorting) is zero, and false dismissed rate (Data Detection that is about to distort is the probability of distorting) is (1/2) ^l, effectively tamper detection.

As shown in Figure 1, the present invention is based on the map vector completeness certification method process flow diagram that insert on summit, the method is totally divided into two aspect: A, vector map watermark embeds algorithm; B, vector map watermark identifying algorithm.

A, vector map watermark embed algorithm, and step is as follows:

(1) divide map vector region;

Map vector pel is divided into the piece of non-overlapping copies.The regional extent of a map vector piece can be considered as the region that a left upper apex by rectangle and summit, bottom right define.Line number and the columns of the piece that map vector is divided are designated as N _rand N _w, the sum of piece is designated as N _b(N _b=N _r× N _w), i (i=1,2 ..., N _b) individual map vector piece is designated as B _i, comprise piece B _ileft upper apex and the summit, bottom right of rectangle of regional extent be designated as respectively

with

with

represent respectively

x coordinate and y coordinate, with

represent respectively

x coordinate and y coordinate.

Here, a pel is only divided in a region unit.Once after a pel is divided in a region unit, all summits of this pel are also all divided in this region unit, even if some summits of this pel may exceed the regional extent of this piece.In Fig. 2, show map vector piece B _iborder and a line chart unit being divided into wherein

example,

with represent respectively vertex v in the PL of line chart unit _jx coordinate and y coordinate.For summit is described

with and B _iuntrue being present in map vector file of border, summit

with

show B with Dark grey _iborder show with dotted line.In all summits of online pel PL, v ₀, v ₁and v ₄exceed map vector piece B _iregional extent, v ₂and v ₃at B _iregional extent in, but all summits of pel PL all belong to map vector piece B _i.

(2) map vector block sort;

According to the number on summit in each region unit, all pieces are divided into two classes: normal piece and empty piece.By piece B _isummit number be designated as NB _iif, NB _i>=0, piece Bi is a normal piece; Otherwise piece Bi is an empty piece.The present invention is embed watermark in normal piece only.

(3) record map vector block type;

Generate one and comprise N _bthe sequence F of individual element, this sequence is used for the type of each of recording step (2),

F＝{f _i|f _i∈{0,1},i＝1,...，N _B}

Wherein, f _i=0 represents that i piece is a normal piece, f _i=1 represents that i piece is an empty piece.

(4) generate authenticating water-mark;

Utilize hashing algorithm, generate the authenticating water-mark of each normal piece in step (2).By piece B _iwatermark information be designated as H _i,

H _i＝{h _i,j∈{0,1},j∈[0,L-1]}

Wherein, L represents H _ithe number of middle bit, h _i,j(0≤j≤L – 1) represents H _iin j bit.

Generate piece B _iauthenticating water-mark H _imethod as follows:

H _i＝blockhash(hash(I(B _i),k,i,M _index),L,K).

Wherein, I () represents the spatial data that obtains and the method for attribute data, and k represents that one for generating the private key of an input parameter of hash (), M _indexrepresent the index value of this map vector, hash () represents an existing cryptographic Hash algorithm, blockhash (H _i ^a, L, K) be illustrated under the control of private key K from bit sequence H _i ^athe method of middle selection L bit.Blockhash (H _i ^a, L, K) and in method, H _i ^a={ h _t ^a| h _t ^a∈ { 0,1}, t ∈ [0, HA – 1] } represents the binary string that hash () generates, and HA represents H _i ^alength, the method is specific as follows:

$\left[\begin{array}{c}\mathrm{tp}=(u_j\&times;i)\%\mathrm{HA}\\ h_{i,j}=h_{\mathrm{tp}}^a\end{array}\right]$

Wherein, u _jrepresent the pseudo-random number sequence U={u being generated by key K _j| j=0,1 ..., j the element of L – 1}.

(5) embed authenticating water-mark;

In this step, the method for utilizing summit to insert, is embedded into the authenticating water-mark generating in step (4) in corresponding normal piece.In a normal, the concrete steps of embed watermark (are supposed piece B as follows _ibe a normal piece, the watermark that embed is H _i):

A. according to map vector piece B _iborder, calculate B _icenter

$\left\{\begin{array}{c}{B}_{c,i}^x=(B_{i,\max }^x+B_{i,\min }^x)/2\\ B_{c,i}^y=(B_{i,\max }^y+B_{i,\min }^y)/2\end{array}\right.$

Wherein,

with

represent respectively center B _c,ix coordinate and y coordinate.

B. generate one with B _c,icentered by, the round CB that r is radius _i(B _c,i, r).The present invention will be at circle CB _i(B _c,i, on circumference r), insert containing watermark summit with Hidden Authentication watermark.For guaranteeing can not exceed piece B containing watermark summit _iborder, the value of radius r should meet the following conditions,

$(B_{i,\max }^x-B_{i,\min }^x,B_{i,\max }^y-B_{i,\min }^y)$

C. authenticating water-mark Hi is converted to watermark sequence W to be embedded _i={ W _i,j| j ∈ [0, N _a– 1] },

$\left\{\begin{array}{cc}{W}_{i,j}=\left\{h_{i,k}\right|k\&Element;[j\&times;52,(j+1)\&times;52-1]\},& 0\&le;j<N_A-1\\ W_{i,j}=\left\{h_{i,k}\right|k\&Element;[j\&times;52,L-1]\},& j=N_A-1\end{array}\right.$

Wherein, W _i,jrepresent sequence W _iin j element, N _arepresent sequence W _imiddle element number.Embed watermark in the magnitude portion of the angle that the present invention represents at double-precision floating points.As shown in Figure 3, the double-precision floating points stipulating in IEEE-754 comprises 3 parts: symbolic component (the 63rd bit), exponential part (52-62 bit) and magnitude portion (0-51 bit).Because the magnitude portion of a double-precision floating points can embed the data of 52 bits, therefore, watermark sequence W to be embedded _ieach element can comprise 52 bit watermark information, i.e. W _ielement number N _afor=

required angle number is also

D. in key K ^dparticipation under, generate a double-precision floating points sequence A _i={ A _i,j| j ∈ [0, N _a– 1], (0≤A _i,j<180) },

$\left\{\begin{array}{c}{P}_{i,j}^b=\mathrm{rand}\left(K^d\right)\%180\\ P_{i,j}^a=1.0/(\mathrm{rand}\left(K^d\right)+1)\\ A_{i,j}=P_{i,j}^a+P_{i,j}^b\end{array}\right.$

Wherein, A _i,jrepresent sequence A _ij element, rand (K ^d) be illustrated in key K ^dparticipation under return a random integers P (P=0,1,2 ...) function.Sequence A _ibe used for embed watermark sequence W _iangle sequence.

E. for each element W of sequence Wi _i,j(j ∈ [0, N _a– 1]), the method for utilizing position to replace is embedded into sequence A _iin j angle A _i,jmagnitude portion, be designated as A by what obtain containing watermark angle _i,j';

F. according to containing watermark angle A _i,j', calculate at circle CB _icircumference on containing watermark summit

position,

$\left\{\begin{array}{c}{r}_j^a=A_{i,j}\&prime;\&times;(\mathrm{\&pi;}/180)\\ v_{i,j}^x=B_{c,i}^x+r\&times;\cos \left(r_j^a\right)\\ v_{i,j}^y=B_{c,i}^y+r\&times;\sin \left(r_j^a\right)\end{array}\right.$

Be designated as V by what calculate according to step e-f containing watermark vertex set _i={ v _i,j| j ∈ [0, N _a– 1] };

G. by V _iin be inserted in map vector containing watermark summit, obtain containing watermark map vector.If this map vector is made up of a pel, will be considered as a pel containing watermark summit and be inserted in map vector; If this map vector is made up of line chart unit or face pel, utilize all watermark summits that contain build new line chart unit or a face pel and be inserted in map vector.

As shown in Figure 5, after the Chinese Railway map embed watermark shown in Fig. 4, increased some bar charts unit.

B, vector map watermark identifying algorithm

(6) watermark authentication and raw data are recovered;

The piece of non-overlapping copies will be divided into containing the pel of watermark map vector; Utilize sequence F in step (3) to identify the type of each; Utilize diverse ways to authenticate the integrality of different pieces.

For an empty piece, if contain summit in this piece, suffer to distort depending on it; Otherwise, think that this piece is by authentication.

For a normal piece, the concrete steps of its verification process are following (to be supposed containing watermark block B _i' be a normal piece):

A. according to the a-b computing block B in step (5) _i' center

and generate one with B _c,i' centered by, the round CB that r' is radius _i' (B _c,i', r').Wherein,

with

represent respectively center B _c,i' x coordinate and y coordinate;

B. search for CB _i' all summits on circumference.By CB _i' the set on all summits is designated as on circumference

table CB _i' j summit on circumference,

with

represent respectively summit

x coordinate and y coordinate, N _crepresent

the summit number comprising;

C. obtain all possible containing watermark vertex set.The all possible sequence containing watermark vertex set is designated as $V_i^p=$ $\left\{V_{i,j}^p\right|j\&Element;[0,N_p-1]\},$ Wherein, $V_{i,j}^p=\left\{v_{i,j,k}^p(v_{i,j,k}^{p,x},v_{i,j,k}^{p,y})\right|k\&Element;[0,N_A-1]\}$ Represent one possible containing watermark vertex set, this set by from

in choose N _aindividual different summit obtains,

express possibility containing watermark vertex set in k summit,

with

represent respectively summit

x coordinate and y coordinate,

express possibility containing the number of watermark vertex set;

D. for in eachly may contain watermark vertex set carry out following 3 steps:

P1. utilize the watermark generation method of describing in step (4) to generate B _i' ' watermark information H _i'={ h _i,j' | h _i,j' ∈ { 0,1}, j ∈ [0, L – 1] }.Wherein, B _i' ' represent not comprise the piece B on middle summit _i'.

P2. utilize c-f and the H of step (5) _i', generate one containing watermark vertex set

represent V _i,j' k summit,

with

represent respectively vertex v _{i, j, k}' x coordinate and y coordinate.

If p3.

piece B _i' comprise it accordingly containing watermark summit, piece B _i' by integrated authentication, delete

in summit with recover raw data, piece B _i' verification process leave it at that; Otherwise, repeating step d until

all set are all completed.

If e.

middle neither one is piece B containing watermark vertex set _i' containing watermark vertex set, think piece B _i' suffered to distort.

Verify after the integrality of each map vector piece, shown all map vector pieces that are tampered.Map vector after the moisture seal Chinese Railway map that Figure 6 shows that Fig. 5 is distorted has occurred to distort in region A, B, C.In Fig. 7, detected after the integrality of each map vector piece, the pel of the map vector piece of distorting is shown as thick lines and is Dark grey.Can find out, the present invention is positioning tampering accurately.

The method embed watermark that utilizes position to replace in the magnitude portion of the angle that the present invention represents in the floating number of double precision, can guarantee the correct extraction at authentication phase watermark information, if map vector piece is not distorted, can accurately calculate it containing watermark summit, and then correctly judge the integrality of this map vector piece, the alert rate of mistake is zero, and false dismissed rate is (1/2) ^l.

Claims (1)

1. the map vector completeness certification method inserting based on summit, is characterized in that:

(1) divide map vector region;

Map vector pel is divided into the piece of non-overlapping copies, line number and the columns of the piece that map vector is divided are designated as N _rand N _w, the sum of piece is designated as N _b, N _b=N _r× N _w, i, i=1,2 ..., N _bindividual map vector piece is designated as B _i, comprise piece B _ileft upper apex and the summit, bottom right of rectangle of regional extent be designated as respectively with

with

represent respectively

x coordinate and y coordinate, with represent respectively

x coordinate and y coordinate;

(2) map vector block sort;

All pieces are divided into two classes, and normal piece and empty piece, by piece B _isummit number be designated as

if

piece B _ifor normal piece; Otherwise, piece B _ifor empty piece;

(3) record map vector block type;

Generation comprises N _bthe sequence F of individual element, the type of each in recording step (2),

F＝{f _i|f _i∈{0,1},i＝1,...，N _B}

Wherein, f _i=0 represents that i piece is a normal piece, f _i=1 represents that i piece is an empty piece;

(4) generate authenticating water-mark;

Generate the authenticating water-mark of each normal piece in step (2), by piece B _iwatermark information be designated as H _i,

H _i＝{h _i,j∈{0,1},j∈[0,L-1]}

Wherein, L represents the number of bit in Hi, h _i,j(0≤j≤L – 1) represents j bit in Hi;

(5) embed authenticating water-mark;

The authenticating water-mark generating in step (4) is embedded in normal piece to embed watermark in normal piece

(5.1) according to map vector piece B _iborder, calculate B _icenter

with

represent respectively center B _c,ix coordinate and y coordinate;

(5.2) generate one with B _c,icentered by, the round CB that r is radius _i(B _c,i, r), will be at circle CB _i(B _c,i, on circumference r), to insert and contain watermark summit with Hidden Authentication watermark, the value of radius r is:

$(B_{i,\max }^x-B_{i,\min }^x,B_{i,\max }^y-B_{i,\min }^y)$

(5.3) authenticating water-mark Hi is converted to the watermark sequence W that will embed _i={ W _i,j| j ∈ [0, N _a– 1] }, W _i,jrepresent j element in sequence Wi, N _arepresent sequence W _imiddle element number;

(5.4) according to key K ^d, generate double-precision floating points sequence A _i={ A _i,j| j ∈ [0, N _a– 1], (0≤A _i,j<180) }, A _i,jrepresent sequence A _ij element, sequence A _ibe used for embed watermark sequence W _iangle sequence;

(5.5) for each element W of sequence Wi _i,j(j ∈ [0, N _a– 1]), be embedded into sequence A _iin j angle A _i,jmagnitude portion, be designated as A by what obtain containing watermark angle _i,j';

(5.6) according to containing watermark angle A _{i, j}', calculate at circle CB _icircumference on containing watermark summit

position,

$\left\{\begin{array}{c}{r}_j^a=A_{i,j}\&prime;\&times;(\mathrm{\&pi;}/180)\\ v_{i,j}^x=B_{c,j}^x+r\&times;\cos \left(r_j^a\right)\\ v_{i,j}^y=B_{c,i}^y+r\&times;\sin \left(r_j^a\right)\end{array}\right.$

Wherein, with

represent respectively v _i,jx coordinate and y coordinate, be designated as V by what calculate containing watermark vertex set _i={ v _i,j| j ∈ [0, N _a– 1] };

(5.7) by V _iin be inserted in map vector containing watermark summit, obtain containing watermark map vector;

(6) watermark authentication and raw data are recovered;

The piece of non-overlapping copies will be divided into containing the pel of watermark map vector; According to the type of each of sequence F identification in step (3);

For empty piece, in piece, contain summit, suffer to distort depending on it; Otherwise, think that this piece is by authentication, for normal piece:

(6.1) according to computing block B in step (5) _i' center

and generate with B _c,i' centered by, the circle that r' is radius

with

represent respectively center B _c,i' x coordinate and y coordinate;

(6.2) search CB _i' all summits on circumference, by CB _i' the set on all summits is designated as on circumference $V_i^c=$ $\left\{v_{i,j}^c(v_{i,j}^{c,x},v_{i,j}^{c,y})\right|j\&Element;[0,N_c-1]\left)\right\},v_{i,j}^c$ Table CB _i' j summit on circumference, $v_{i,j}^{c,x}$ With $v_{i,j}^{c,y}$ Represent respectively summit $v_{i,j}^c$ X coordinate and y coordinate, N _crepresent V _i ^cthe summit number comprising;

(6.3) obtain all possible watermark vertex set that contains, the sequence containing watermark vertex set is designated as $V_i^p=\left\{V_{i,j}^p\right|j\&Element;[0,$ $N_p-1\left]\right\},V_{i,j}^p=\left\{v_{i,j,k}^p(v_{i,j,k}^{p,x},v_{i,j,k}^{p,y})\right|k\&Element;[0,N_A-1]\}$ Represent one possible containing watermark vertex set, by from $V_i^c$ In choose N _aindividual different summit obtains,

express possibility containing watermark vertex set

in k summit,

with

represent respectively summit

x coordinate and y coordinate,

express possibility containing the number of watermark vertex set;

(6.4) for

in eachly may contain watermark vertex set

(6.4.1) utilize the watermark generation method of describing in step (4) to generate B _i' ' watermark information H _i'={ h _i, _j' | h _i, _j' ∈ { 0,1}, j ∈ [0, L – 1] }, B _i' ' represent not comprise

the piece B on middle summit _i';

(6.4.2) generate one containing watermark vertex set $V_{i,j}\&prime;=\{v_{i,j,k}\&prime;(v_{i,j,k}^x\&prime;,v_{i,j,k}^y\&prime;)|k\&Element;[0,N_A-1]\},v_{i,j,k}\&prime;$ Represent V _i,j' k summit, with

represent respectively vertex v _{i, j, k}' x coordinate and y coordinate;

If (6.4.3) piece B _i' comprise it accordingly containing watermark summit, piece B _i ^'by integrated authentication, delete

in summit with recover raw data, piece B _i' verification process leave it at that; Otherwise, repeating step (6.4) until

all set are all completed;

(6.5) if

middle neither one may be piece B containing watermark vertex set _i' containing watermark vertex set, think piece B _i' suffered to distort.

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