IMAGE

SCOPE OF TECHNICS

The invention refers to a method and a marking(image) for verification and protection against counterfeit by means of encrypted modulation of spatial location of predefined encrypting elements of the applied marking, as well as a method for verification and control of the encrypted modulation of the spatial location of the predefined elements by means of decryption and comparison for authentication of the originality against counterfeit.

STATE OF THE PRIOR ART

Methods are known for protection against counterfeit by means of modulation of the characteristics of the elements of a visible marking(image). For instance, a patent document BG63518B1 reveals a device for recording of one and several, single and multistage, two or three-dimensional encrypted markings over documents, securities and et c. for protection and control of the originality. That device could encrypt into visible number by means of offset of elements, like digits(signs) or holes of perforation. A document BG6352B1 disclose a multimedia marking with hidden information, acquired by means of different step of offset of some of the elements of the marking.

In the cited documents it is not revealed an encryption by means of a big total variety of possible numerical interpretation of the spatial modulation of the elements of the security markings(images). There are not known other documents disclosing the protection against counterfeit by means of encrypted modulation in the spatial location of defined encrypting elements of the image. TECHNICAL FIELD OF THE INVENTION

The present invention aims to present a method and a marking(image) for protection against counterfeit by means of encrypted modulation of spatial location of defined encrypted elements of the marking(image) and an encryption of information, which are meant for a subsequent control and protection against counterfeit. The goal is achieved by virtue of the big total variety of possible numerical interpretations of the spatial modulations of the selected elements of the security markings(images).

In the modem methods for encryption, diffusions and confusion are two important elements in providing reliable encryption. Whereas the diffusion is the propagation of the influence of the plaintext properties over the encrypted text while the confusion is the obscuring of the relations between the elements of the non-encrypted with the elements of the encrypted text. The achieving of these basic principles is accomplished by imposing transformations of great total varieties and in that way to maximize the cost of possible probabilistic attacks against the system with a view to detecting the encrypted information and creating a fake copy of the security feature.

Let us consider the most commons scenario, in which we have an image composed of elements - dots or others, which are situated in the space of the image and constitute the image. According to the present method defined elements are selected from the image. The selected elements form a group of encrypting elements of the image and to any of these selected elements is assigned a set of possible positions in a two, a three or a multidimensional spatial domain. The assigned positions of each of the elements do not go outside the scope of the space of the image as well as do not change a visual representation of the image, i.e. the image remains the same as a visual perception. The acquired set of positions represents a main initialization factor in the encryption process as it defines the positions, in which any element o the group of encrypted elements can be situated. For each position of the set of positions, that belong to the element of the group of encrypted elements, is given a specific numerical, alpha-numerical or another representation. A particular representation for each position can be a geometrical shape, an element of a binary, a binary-decimal or other code or such of an any kind of notation - decimal, hexadecimal et c. The so-created numerical representation allows to carry out pennutations(combi nations) over interpretations of the positions and thus to achieve the great variety in the selection of different combinations for any single encrypting element.

A certain combination of the numerical representation is set to each of the encrypting elements and to so-defined combination plays the role of an encryption key. The encrypting combination (encryption key) can be randomly generated by means of a random selection of a variation of the numerical presentation of the positions of anyone of the encrypting elements The information, subject to encryption in the image, is transformed to a sequence of signs(elements) of the specified numerical representation of the positions of the encrypting elements. Any sign of the so-acquired sequence determines the spatial location from the original position of one or more encrypting elements. This modulation of the spatial location is carried out according to the relevant specified combination(key) of the numerical representation of the corresponding encrypting elements. Any sign is connected to the identical one of the numerical representation of the relevant encrypting element thus the sign of the numerical representation is related to the corresponding positions and defines the spatial location of the encrypting element in the two, three or multidimensional space domain.

The verification is accomplished by a decryption in a reverse order. Initially the spatial location of the encrypting elements is determined from their original position in the encrypted image. Based on the defined positioned and the corresponding combination(key) it is specified the relevant sign of the numerical representation for each of the encrypting elements. The acquires sequence is transformed to the information that is encrypted into the image and is used for the subsequent control and authentication of the originality against counterfeit. The encrypted marking(image) can take a form a serial number, a logo, a sign or another graphical representation, and the information can be unique personal data of the protected object.

The encrypted marking(image) for protection against counterfeit by means of the encrypted modulation of the spatial location of the predefined encrypting elements is composed of elements, dots, perforated holes or others, which are located in the space of the image.

The marking(image) includes defined encrypting elements which are formed in the group of encrypting elements with the specified set of positions in the two, three or multidimensional space domain. These positions have their defined numerical representation that includes digits and signs. The selection of the positions is such that there is no overlapping of the positions of the neighbour elements or the position to be outside the space of the image itself, or to alter its visual representation.

The modulation of the spatial location is rendered according to the corresponding combination(key) of the numerical representation of the relevant encrypting elements. As any sign is related to its matching sign of the numerical representation of the corresponding encrypting element, which connects the sign to the corresponding position and thus it is defined the location of the encrypting element into the two, three or multidimensional space of the obtained encrypted image.

The information subject to encryption is transformed to the signs of the numerical representation and by means of this transformation it is acquired the transformed information. Advantages of the present inventions consist in that it allows the great total variety of combinations of the numerical representations - keys for encryption for any single marking( image) which leads to a great reliability and security against unauthorized manipulation, decryption or imitation of the security marking.

DESCRIPTION OF THE ENCLOSED FIGURES

Fig.1 Shows the encryption in the marking(image), that is a laser microperforation, by means of modulation of location of the elements (perforated holes) of the marking in the two- dimensional space.

Fig2. Depicts decryption and verification of the marking(image), that is laser microperforation, by means of modulation of location of the elements (per forated holes) of the marking in the two-dimensional space.

Fig3. Illustrates encryption by means of different variants of positions of the encrypting elements in the marking(image)

Fig.4 Shows encryption in the marking(image) by means of transformation from the three- dimensional to the two-dimensional space for achieving more combination of the numerical representations.

Fig.5. Reveals protection of a passport by means of the marking(image) that is the microperforation of the face image of the owner of the passport.

EXAMPLES OF PREFERRED EMBODIMENTS

One of the preferred embodiments of the invention is illustrated on fig.l , where there is an image (1) representing a laser microperforation of a serial number over the protected object. From any one of signs of the serial number are selected two elements (2), that are the encrypting elements and form the group of encrypting elements (3). For the group of encrypting elements, it is assigned the set of possible positions (4). The positions (4) defines the possible position of the element in the particular case in the two-dimensional space. The selection of these position is carried out in the way that they do not overlap or step over the position of their neighbour elements as well as not to go outside the space of the image. In the present preferred embodiment, we have nine positions in the two-dimensional space. As the central point is the position where normally by default are situated the elements (2) in the image (1). For the positions (4) it is defined the numerical representation (5) as for each of the positions from top to bottom and left to right is assigned a number from "0" to "8". On the next step it is set a combination (6) of the numerical representation (5) for anyone of the encrypting elements (2) of the group of encrypted elements (3). The combination (6) represents the encryption key for carrying out the encryption. The key (6) is formed by random permutations from (6.1.) to (6.8.) for anyone of the corresponding elements (2) of the group of encrypting elements (3).

Information (7), meant for the encryption, is converted to the signs of the numerical representation (5) by carrying out the transformation from a decimal to a nonary notation and a transformed information (8) is acquired. Each of the signs of the transformed information (8) defines the positions of the elements (2) of the encrypting group (3). A first sign "1" according to (6.1.) determines position 1 , top and left for the first of the encrypting elements, and a last sign "6" as per (6.8.) defines the potions represented by "6", i.e. straight down from the central position.

The obtained encrypted image (1) is meant for protection of a bond (9), where the encrypted information is an amount of the bond (9) and is applied by means of a laser microperforation. While on the fig2. there is a process of decryption and verification of originality shown. We have the bond (9) with the microperforation of the encrypted image (1). The position is found of each of the encrypting elements (2) of the group of encrypting elements (3) in the set of positions (4) as the comparison is done between the current position of the element and the positions of the neighbour elements in the image. In the particular example the first element of (2) is top and right. The position top and right corresponds to the sign "1" of a permutation (6.1.) of the key (6), which means sign "1". That is repeated for each of the elements (2) of the group (3) and thus the transformed information (8) is achieved, after that (8) is converted form the nonary to the decimal notation and the encrypted information (7) is obtained. The encrypted information (7), that is the amount of the bond (9), is compared with the amount written on the bond and the validity is authenticated.

A detection of the positions of the encrypting element (2) can be achieved by means of the magnifying lens and a grid for defining the place of (2), after that a code table cab ne used to determine the sign from the key (6) and to obtain the transformed information (8) and then the encrypted information (7). Other option is the utilization of a camera or an image sensor, controlled by a personal computer and by capturing the image (1) and its image processing by a software using standard methods for image processing and detection of the position of the elements (2) of the group of encrypting elements (3), decryption by means of the key (6) and comparison of the information (7) with the one of the bond. On the fig.3. is presented another preferred embodiment of the present invention. Here the image (1) is a sign in the shape of a company logo over a label (10) placed over a product for protection against counterfeit. The logo is a set of dots. Among the dots are selected elements

(2) that compose the group of encrypting elements (3). For each of the elements (2) is set two variants of the set of positions (4), respectively (4.1.) and (4.2.) as well as the corresponding numerical representations (5). For each specific marking is set the relevant combination(key) (6) from the different permutations of the numerical representations (5) of each of the elements (2) of the encrypting group (3). The representations (5.1.) and (5.2.) alternates for obtaining (6.1.) to (6.9.). We have a batch number that is the information for encryption (7). The information (7) is converted to the transformed information (8), by a transformation - digit to sign and digit to digit, where the digit defines a number of the letter and thus the letter itself, i.e. the sign. Each item of (8) defines the positions of the relevant element (2) according to the key (6). E.g. "I" via (6.1.) sets the position marked with "I" and so on with any element of the group (3). Then the image (1 ) is applied by means of the ink-jet printing over the label (10). The decryption for verification is carried out in a reverse order and the key (6) is needed. Another preferred embodiment is depicted on fig.4, where the position (4) is presented in a three-dimensional space (domain). Let us have the protected object that is a personal identity card (11). The card is protected by the image (1) that is a serial number of the identity card (1 1). The encrypting elements (2) are selected, which constitute the group of encrypting elements (3). The set of positions (4) of the encrypting elements (4) is set, which arc represented within a cube of the three-dimensional space. The set of positions is then converted to the two-dimensional space (4.1.). The transformation is done by shifting the positions from one plane to another by selection a geometrical projection - orthogonal, polar or an unfolding of the projection planes and et c. standard methods. To the obtained set of positions (4.1.) is assigned the numerical presentation (5), that includes the digits from 0 to 8 and letters from "A" to "H. The bigger number of signs of the alphanumeric representation allows for a significantly bigger number of permutations for the set of positions and thus a bigger number of combinations of the keys and respectively more security. The key (6) is generated from the permutations of (5). The information for encryption (7) is a merge of a date of issue and an expiry date of the document (11). By means of converting from decimal to hexadecimal notation (7) is transposed to the transformed information (8). And the signs of (8) via the key (6) define the positions of the elements (2) of the group of encrypting elements

(3) . The image (1) is applied onto the personal card by means of a laser engraving.

On fig.5 is visualized another embodiment of the present invention. The protected object is a passport (12). The image (1) is a face image of a holder of the passport, which is represented by means of elements that are dots, from which are selected the encrypting elements (2) constituting the group of encrypting elements (3) and the positions (4) are set. The acquired set of positions (4) is given alphanumeric representation (5) and the combination of the key (6) is generated.

The information for encryption (7) is a set of personal data of the holder of the passport - name, surname, family name etc., in order to avoid a forgery of that information on the passport. The information (7) is presented like digits by means of converting the letters into digits where the order of the letter response to the corresponding digits. Then the transformation is done from decimal to nonary notation to obtain the transformed information (8). The signs of (8) defines the position of (2) in the image (1) that is applied by means of a laser micro-perforation on the passport.

APPLICATION OF THE INVENTION

The invention has a huge number of applications, that are related of the protection against counterfeit and forgery of securities, banknotes, personal identity documents - ID cars, passports etc. As well as a protection any kind of products and goods against counterfeit and authentication of the originality and track and trace.