PhotoWaterMark technology of counteraction to falsification of credit cards: Holographic approach

The counteraction to methods of a falsification paper, and recently and plastic, documents is a traditional and urgent task of protection of carriers of the information. One of key elements for many documents is the photo. It is possible to not speak what economic and legal harm the falsification of photos puts. Such documents as the passport, driver's certificate, credit or identification card, medical policy and others here concern.

Now the new means of protection based on last achievements physicists, chemistry, microelectronics are intensively developed. The most attractive decision embedding of microchips looks. Digital data presentation, provides convenient input and editing of data, a high noise stability, simplicity of data read-out. However similar simplicity is attractive and to burglars. Experiments with breaking the microchips which have been built in the passport, have shown rather low safety "to this technology - all the data stored an electronic kind, became accessible to "malefactors", including prints of fingers, a photo, the coded and usual text" [1,2]. Other example: in the beginning of December, 2006 clients of Of Foreign trade bank (FTB24) have started to address with complaints in Bank - " from their cards means have been written off... As Irina Busheva has informed the vice-president of the credit organization, Malefactors have established the special imperceptible devices allowing on six capital cash dispenses FTB24 To read out data of plastic and pin-codes " (magazine " Finance. ", 49, 2006, rus). Swindlers managed to remove about $100 thousand, Which FTB24 it was necessary to return naturally to clients, and also to replace more than 4 thousand plastic cards.

The basic lack of existing means of protection of official documents consists in absence of conditional dependence between event of substitution of object of identification (a photo of the owner of the document) and presence of object of means of protection (for example, the protective optical hologram, the built in microchip, etc.). Substitution of object of identification (photo) at preservation of the protective hologram, for example, does not entail a conclusion about a fake of the document.

The present resource illustrates technology PhotoWaterMark for protection of photographic documents on a paper or plastic basis. An example of the documents containing a photo of the owner, plastic cards of "Citybank" can serve:

Technology PhotoWaterMark represents a combination of the steganographic approach of concealment and the cryptographic approach of enciphering of data that provides practical impossibility of breaking. And, the basic inconvenience for breaking consists in analog representation of hidden data. The essence of the steganographic approach consists in concealment of the fact of transfer or introduction of the information in the carrier. One of such methods of [3, 4] - Holographic approach to embedding ... of the latent watermarks in photos is put in a basis of the present technology. It is established that a Fourier transformation of watermarks embedded in the frequency domain with a shift relative to the coordinate origin is a digital Fourier hologram. Or otherwise speaking, embedding of a watermark in an image spectrum, it is equivalent to embedding of a watermark the hologram in the image.

Let's consider procedure of the control of documents. Schematically process of identification, for example owner ID of a card, it is possible to present as set program and the means working in a mode of real time:

The photoimage is read by the CCD-scanner, is exposed to transformations for detection of a hidden watermark, and then the watermark is shown on the monitor. In figure, the watermark is submitted as a mark copyright ©.

In a basis of a method of the embedding, hidden data, the principle of an interference is put. The essence of a method consists in synthesis of the digital hologram of a watermark and additive-multiplicate mixing of the received hologram with the image-container:

For realization of return procedure, i.e. procedure of restoration of a watermark from the hologram, it is enough to execute two-dimensional transformation Fourier, if parameters of synthesis of the hologram, and in particular spatial carrier are certainly known. In real time, this function is realized by means of digital signal processors (DPS). For example, DSP firms Texas Instruments, allow to execute this procedure for shares of second. During restoration of a watermark, it is possible to observe both the restored object, and its holographic image:

The major element of any information system is enciphering the confidential information. The considered approach is not exception - two-dimensional cryptograms are integrally built in a chain of transformations of two-dimensional images:

Stability of the code is defined exclusively by stability of a confidential key. Thus, analog execution of means of protection of object of identification (a photo of the owner) and the latent character of built in data represents "poorly attractive" object for digital breaking, and attach of a cryptographic subsystem to the steganographic system of concealment of data provides a powerful barrier to not authorized intervention. At a stage of working off of algorithms researches on embedding of the latent watermarks in carriers on a paper and plastic basis have been conducted. These researches are presented on page Results of experiments... and Experiments to restore HWM from art reproductions on paper carriers. The special software is developed for carrying out of experiments, allowing to change level of stability to influence of procedures of a photo printing and scanning by means of factor of strengthening of a signal of a watermark: a software package the Photographic watermark.

In summary, it is necessary to note, that the offered technology can be considered as an additional degree of protection of documents to existing. For example, behind microchips there is their conclusive advantage - a simple and convenient way of reading of greater files of figures on the screen of the monitor. A place of technology PhotoWaterMark for embedding of the latent watermarks is protective function at an analog level.

The present technology also can find application for the latent transfer and storage of the confidential information on the Internet and cellular communication [5]. The additional information about Digital watermarking can be received on pages Wikipedia.