Document forgery detection system.
Patent 5432506 USA, IPC G 06 F 15/30.- Published 11.07.95.
Document forgery detection system.
The current state of technology of optical scanners and laser printers allows for easy and inexpensive high-precision copying of various securities and documents. In many cases, counterfeit documents produced in this way cannot be distinguished from genuine ones. As a result, banks, financial and other institutions suffer large material losses.
This patent proposes a method and system for protecting securities and other documents from counterfeiting and detecting their counterfeiting.
The principle of protecting documents from counterfeiting consists of printing a unique code on them, generated by a computer using a secret program using the data contained in the document. This code is checked at the place where the document is presented.
The system for checking the authenticity and detecting counterfeiting of documents at the place of issue of the document contains (using checks as an example):
- a device for inputting constant and variable data into the computer, which must be printed on checks;
- a computer and a program for selecting specific, previously entered data and converting it into a new sequence of characters representing a secret code;
- means for printing the usual constant data and a unique code on the check form.
The check verification or payment point must have: — a device for inputting into the computer the data read from the check, including the unique code;
- a computer with a program for reading specific data from the check and converting it into a check authentication code;
- means for comparing the unique code and the authentication code;
- means of signaling the discrepancy between these codes, i.e. the check has been forged.
The system also includes means of communication for transmitting from the organization that issued the check to the verification point the unique code generation program and the verification code.
A potential forger cannot know what data on the check was used by the unique code generation program, even if the check was reproduced by the printer with high accuracy.
When generating a unique code, it is desirable to use the maximum possible number of permutations and combinations to eliminate any possibility of its disclosure. Random selection of one or more characters from any field of the record makes it possible to obtain a large number of variables for generating the code.
The program for generating a unique code can be changed as often as desired. The check verification or payment point must have all program options.
The characters used to generate a unique code can be numbers, letters of any alphabet, graphic symbols, etc. In an alternative embodiment of the system, the main computer can simultaneously act as an authority issuing checks and a remote point for checking their authenticity. In this case, it is necessary to have communication lines (for example, telephone lines) from the main computer to remote points. The invention has a number of characteristic features that are desirable to be used in combination, although each of them is effective separately.