EP1346512A1

EP1346512A1 - Method and device for protecting documents or for verifying authenticity of a document using an encrypted information produced by said method, and documents protected by said encrypted information

Info

Publication number: EP1346512A1
Application number: EP01989661A
Authority: EP
Inventors: Patricia Etienne; Roger Suanez
Original assignee: Eracofa SA
Current assignee: Eracofa SA
Priority date: 2000-12-28
Filing date: 2001-12-26
Publication date: 2003-09-24
Also published as: WO2002054667A1; CA2433224A1; FR2819068A1; FR2819068B1; US20040062389A1; JP2004523155A

Abstract

The invention concerns a method for producing an encrypted information from character strings and numeric values of specific size and representing items to be protected for identifying forgery of administrative documents or documents delivered by public authorities comprising the following steps which consist in: condensing said strings into several numbers of n figures smaller in size than the number representing the size of the strings to constitute a first set of m intermediate results of n figures; transforming said m intermediate results, with an algorithm randomly drawn among several, into a second result of n figures expressed in base 10 produced by a matrix converting characters of an alphanumeric base into digital characters of a decimal base stored by a computing system; converting said second result expressed in base 10 into another so-called encrypted result with the same number of n figures, expressed in a mathematical base randomly selected by the computing system among a specific selection of available conversion bases stored by the computing system, to obtain an encrypted identifier.

Description

Device and method for protecting documents or verifying the authenticity of a document, by using encrypted information produced by the method, and documents protected by said encrypted information.

The present invention relates to a device and method for protecting documents or verifying the authenticity of a document, by using encrypted information produced by the method, and documents protected by said encrypted information. The invention applies, for example to any identity or regulatory documents or to any document requiring a certain authenticity, in particular to documents and nominative documents of legal or natural persons, such as residence permits, work permit, security card social security or health insurance, passport, registration card, driving license, hunting or fishing license, or other titles, forms or documents issued by the authorities of a country.

It is known, in particular from patent application EP 1 003 324, a system making it possible to prepare documents resistant to counterfeiting. These documents include images that incorporate secret data. This document teaches a process associated with incorporating information hidden in images. This system makes it possible, for example for passports, to hide machine-detectable multi-information in an image present on the document. It is the analysis of the image and the use of this information that subsequently allows the authentication of the document. However, this system does not make it possible to build a simple machine, easily transportable and which can do without image analysis means to enable the authenticity of a document to be certified.

The object of the present invention is to overcome this drawback by proposing, first of all, a method for preparing encrypted information.

This object is achieved by the fact that the method produces encrypted information from character strings and numerical values of determined size and representing headings to be protected in order to identify falsifications of administrative documents or documents issued by public authorities, characterized in that 'it comprises : a step of condensing these chains into several numbers of n digits of size smaller than the number representative of the size of the chains to constitute a first. set of m intermediate results of ¹ n digits; a step of transforming these m intermediate results, by an algorithm drawn randomly from among several, into a second result of n digits expressed in base 10 produced by a matrix for converting the characters of an alpha numerical base into numerical characters of a base decimal stored by a calculation system; a stage of conversion of this second result expressed in base

10 in another result said to be encrypted with the same number n of digits, expressed in a mathematical base chosen randomly by the calculation system from a determined choice of conversion bases available and stored by the calculation system, to obtain an encrypted identifier. According to another particularity, the alphabetic character strings and the numerical values contained in the protected headings form, after conversion to a decimal base, the terms of algebraic functions constituting each of the algorithms, one of which is drawn randomly among several, numbered with ( 0 to n-1), the number of the algorithm used for the transformation being fixed by the modulo 'n) of the decimal value of the character (x), drawn randomly or chronometrically in an interval of the clock time, between two terminals.

According to another particularity, the result of the transformation by the asymmetric mathematical function of this algorithm is then expressed in a base (y) which is also drawn randomly between two other bounds.

According to another particular feature, this result is always represented by a constant number n of characters, the rows of which are numbered and contain units expressed in this base (y) drawn at random.

According to another particularity, the character (x) which determines the base (y) used to determine the so-called encrypted result is chronologically inserted among the characters which represent this encrypted result, at rank (q) defined by the integer quotient of the value of (x) divided by (n), shifting by one row to the left, the characters of the encrypted result having a weight equal to or greater than the defined rank.

According to another particularity, at the end of the encryption, the random key character (x) is inserted at a predetermined rank by the designers of the calculation or calculated device.

According to another particularity, the character strings of determined size and representing headings to be protected in order to identify falsifications of administrative documents or issued by public authorities consist of truncations of alphabetical headings' formed by long alphanumeric entry fields in which are taken into account that a significant and constant number of characters belonging to a base 36 for converting these truncations into figures between 0 and 35, the memory registers concerned and not indicated being set to zero. According to another particularity, the method elaborates encrypted information from a first truncation of the name of a being and a second truncation on a second information identifying the living being by the steps which consist: a) in converting into integer each of the letters of the two truncations in decimal numbers; b) to calculate for each numerical value representative of a ^• character an intermediate result; c) adding each of the intermediate results to obtain a first result called name code and representative of coded patronymic information; d) determining a second result called Ident Spy according to a “random” algorithm drawn randomly from among several; e) generating an encrypted identifier, of the same size as the two truncations from the number representative of the second result obtained in the previous step, a plurality of numerical values representative of characters by a plurality of conversion algorithms executed on this result and transform the digital values thus obtained into output and between 0 and 61 in letters or numbers by using a conversion matrix defined by a base chosen randomly for this calculation which makes it possible to obtain the encrypted identifier;

According to another particularity, the method consists in inserting a character representative of the base number used in the preceding calculation and in inserting a second character representative of the position of insertion of the first character and of the algorithm number used in step d .

According to another particular feature, the conversion of step a) is obtained by using a first determined base for transforming characters into figures.

According to another particularity, each intermediate result is constituted by the numerical value corresponding to the character of a character string constituting a truncation multiplied by the value of the base at a power corresponding to the value of the rank of the character in the string.

According to another particularity, each “random” algorithm drawn at random takes into account the name code, a date identifying a significant event in the living being and the algorithm number used to develop this result. According to another particularity, the random algorithm whose number is drawn randomly to be used in step d is determined by:

- either the addition of the code-name information and the date reduced by the representative number of factorial 8 if the random drawing defines the first algorithm; - either the code-name minus the date to which is added the factorial of the number 8 minus the algorithm number if the random draw defined algorithm 1;

- either the name code plus the date minus twice the factorial of the number obtained by subtracting the algorithm number from 8 if the algorithm is 2; - either the code-name minus the date plus twice the factorial of the number obtained by subtracting from 8 the algorithm number if the algorithm is three, ie twice factorial 5; - either the code-name plus the date minus ^" three times factorial from the number obtained by subtracting from 8 the algorithm number, when the algorithm is the date, that is to say 3 times factorial 4;

- either _. the code-name minus the date plus 3 times factorial of the number obtained by subtracting 8 the algorithm number when the algorithm is number 5, i.e. code-name minus the date plus 3 times factorial 3.

According to another particular feature, each of the intermediate results of the algorithm defined in step b) is obtained by multiplying the numerical value representing the character belonging to one of the truncations by the numerical value representative of the base raised to a power corresponding in the reverse order of the corpuscles organized according to the first then the second truncations, then possibly the other truncations.

Another aim is to propose a device for protecting documents or verifying the authenticity of a document. This object is achieved by the fact that the device for protecting documents or verifying the authenticity of a document includes means for entering and storing character strings and numerical values of determined size and representing headings to protect to identify falsifications of administrative documents or documents issued by public authorities;

a means of executing a condensation of the character string by a first calculation algorithm on a value obtained by a conversion in a determined and fixed calculation base allowing the device to develop a plurality of stored digital values representative of the strings stored in the form of a plurality of intermediate results;

means of transforming this plurality of results into a finite succession of digits by using an algorithm from a set of calculation algorithms; means of transforming the digital result obtained by the use of a transformation base drawn randomly from among several, these transformation means thus elaborating an encrypted identifier formed of numbers and letters and memorized, means for inserting into the encrypted identifier a first character representative of an identifier of the calculation base in a random position defined by a second character inserted in a fixed position of the encrypted identifier for define, on the one hand the position of the first character and on the other hand the number of the algorithm chosen randomly from among several.

According to another particularity, the strings of characters and of numerical values consist of at least one truncation of the name and of other information identifying a being and the device comprises means of memorizing a date representative of an event related to the 'to be.

According to another particular feature, the document protection device comprises means for selecting a second calculation algorithm chosen randomly from several algorithms, this second calculation algorithm developing, from the numerical value obtained and the date of the event, a second numerical result.

According to another particular feature, the document protection device comprises a printer making it possible, on the one hand, to write legible alphabetical information making it possible to identify the natural or legal person, for example the name, and second information such as, for example. example the first name, identifying the being and on the other hand on the document an authentication number consisting of the encrypted identifier and the two characters inserted in the encrypted identifier.

According to another particularity, the device for verifying the authenticity comprises means of introducing a truncation of the identification of the natural or legal person, for example, the name and the first name identifying the being, means of introducing the authentication number of the document and of the calculation means allowing, by an algorithm executed on a second character placed in a fixed position, to determine, firstly the position of the first character representative of the identifier of a calculation base and secondly the number of the algorithm drawn at random and used in the conversion calculation to convert the alphabetical information constituted by the first and second truncation of the identifiers of the natural or legal person into an encrypted code which will be compared with the value of the encrypted code obtained from the document's authenticity number.

Another object of the invention is to provide a protected document. This object is achieved by the fact that the protected document includes, in addition to the identification information of the person in possession of the document, information calculated from a determined truncation on the identification of the natural or legal person, by example the name, the first name and the date of birth, according to a calculation algorithm defined randomly among a plurality of algorithms after conversion of the truncation in a first base, the calculated information is then expressed in a determined calculation base randomly to form an encrypted identifier, a representative character of the random basis of calculation being inserted into the encoded information in a position ^random defined by a character inserted in a given position, this fixed character representative position in the first base calculation , a value whose quotient by a prime number, provides the position of the id character tification of the random coding base and the rest of the quotient the number of the algorithm drawn randomly from the plurality of algorithms. Other features and advantages of the present invention will appear more clearly on reading the description below made with reference to the accompanying drawings in which:

- Figure 1 shows a schematic view of the steps of an alternative implementation of the method for calculating encrypted information allowing authentication of a document;

- Figure 2 shows the application of this calculation method to a specific example with the intermediate results stored during calculation on the device implementing the invention;

- Figure 3 shows a schematic view of the steps of a second variant of implementation of the method of calculating encrypted information allowing authentication of a document.

The invention will now be described in conjunction with Figures 1 to 2. The method implemented by the device consists in introducing into a first stored register of the device of the invention an alphabetical information representative of a truncation fixed at 5 characters, the identifier of the natural or legal person for example, the name of the person for whom the document is issued and whose document must be protected against fraud or whose authenticity is sought in the document presented.

In a second memorized register containing two other characters, the user enters a second alphabetical information representative of a truncation of a second identifying word in letters, for example the first name. A keyboard associated with the means known to those skilled in the art allows this operation. A display device associated with the calculation device allows the user to check the accuracy of the information entered or calculated.

In a third register, we introduce the 6 digits representing a significant event characteristic of the being or the legal person for which an authority seeks to verify the authenticity of a document or whose authority seeks to protect a document that she will give it to him. This event can be for example the date of birth, if it is an identity document or the date of obtaining the document or authorization, for, for example, a hunting or driving license or an import authorization. This step is represented by step (E1) of FIG. 1. Each of the letters of the first and second truncations is converted during a step (E2) by the use of a correspondence matrix in a first fixed base. or determined, for example of rank 36 as defined in appendix 1, between the letters of the truncations and the numerical values defining this base. Thus, in a row base 36 represented in appendix 1, the letter e represents the numerical value 14, the letter t the numerical value 29 and so on. These representative numerical values in the fixed base of the characters of the truncation, will then be transformed during a step (E3) into numerical values whose value will depend on the position of the numerical value representative of the character in the truncations by multiplying each values numerical by the rank of the base, that is to say the value 36 raised to a power representative of the position of the character or of the numerical value in the succession of the two truncations, these positions being determined in the opposite direction. Thus the rightmost digit 10 which corresponds to the letter a, is assigned an exponent 0 while the leftmost value 14 which corresponds to the letter e, is assigned the exponent 6 by the calculation device, which means that 14 will be multiplied by the rank of the exponent base 6, that is (36) ⁶ to give a first value V1 = 14 * 36 ⁶ , a second value V2 = 29-36 ⁵ , etc. .as represented in step E3 of FIG. 1. Each of the values V1 to V7 thus elaborated constitutes an intermediate result which will be added to the other intermediate results in step (E4) to give a first result 32259388798 called "code name" . On this first result, the computing device will apply an algorithm chosen randomly from a plurality of algorithms. In fact, it is the number N of the so-called “random” algorithm which is “random” because defined by a random draw. The step (E5) shows for example in FIG. 2 that the random algorithm number 2 is chosen since the random drawing has released the number 2. The application in step (E6) of the algorithm number 2 on the value representative of the first result “code-name” to which is added the digital truncation constituted, for example, by the third truncation, to enable the production of a second result which is identified in FIG. 2 by the name Ident Spy. From this second result 32258828708 thus obtained by application of this algorithm, the calculation device will produce in step (E7) n alpha-numeric values C0, C1, ..., Cn. The number n of numerical values obtained from of the second result, corresponds to the same number of characters in the first and second registers containing the stored truncations. Each of the n calculation algorithms executed by the calculation device is as follows. The first algorithm divides the second result by the value (61) of the rank of the fixed base chosen at random as an output, for example between bases of rank 37 to 63, all raised to the power n-1 (n representing the position by counting from the right of the calculated numerical value Cj. The device thus calculates a first result of which it arranges the decimal part ^' in a register and retains the whole part as the first numerical value CO. In the example in Figure 2 32258828708/61 ⁶ = 0.62613731, the character CO is 0. Each character following C1 to Cn is calculated by taking the decimal value of the preceding character, in this case 0.62613731 and by multiplying by 61 = 38.194376 to deduce from the whole number the value C1 = 38. The numerical values CO to C6 obtained are represented in appendix 3 by a table of these values C0 to Cn. Each of these values C1 to Cn will be transformed in step E9 into an alphabetic character or figure by the use of a conversion matrix according to a base whose number is drawn randomly in step (E8) between a base whose rank is between the values 37 and 63. Each of these values represented in appendix 3 and converted into the base of rank 61, will correspond to a letter or a number. Thus the numerical value C1 = 38 corresponds to the character C in the base 61 and the numerical value31 corresponds to the character v (see appendix 2). This transformation will thus allow step E9 to develop an encrypted identifier called “cryptident” (FIG. 2). The device will insert at step (E12) in this encrypted identifier a first character "Key 1" deduced by a determined algorithm from the rank of the base. In the example of figure 2, after having converted the representative number of the rank (61) of the base into a character z by a conversion algorithm represented in the column Choice Base output of the matrix of appendix 2, a another random draw allows in step E11, to define the insertion position of this first character "Key 1" basic output conversion and an algorithm for calculating a second character "Key 2" to define the position of the first character "Key 1", by exploiting the "random" algorithm number used in step E5 and the numerical value representative of the position drawn at random in step (E10), to extract a value numeric transformed in a fixed calculation base of rank 36 represented annex 1 in an alphabetic or numeric character Key 2, (I in the example figure 2, X in the example figure 1). This second character Key 2 is inserted in step (E12) in a fixed position determined by the device to define Information that is called "spynumber".

Thus, the document protection device will understand these different algorithms, the storage means and the definition of the fixed position of the position character as well as the matrix tables for converting the different numerical values obtained during the calculations to convert these numerical values. in letters or numbers. The row entry base (36), appendix 1, is defined by the first 9 digits to which are added the 26 letters of the alphabet in lowercase letters. The output base, the rank (61) of which is read in the column Choice Output Base, appendix 2, is defined from the base (36) = a and by adding the capital letters, A and B for the bases 62 and 63. The extension of the characters included in the base of rank (63) is defined by adding after the capital letters the character dash and the character dot, as represented in appendix 2 column Value Character .

The document authentication device allows, after entering the letters in the registers defining the truncation, to recalculate an encrypted identifier, which will be compared to the cryptident authentication numbers deducted from the "Spy number" represented in the example of Figure 2 on the document. If the encrypted identifier value, calculated by using the encryption base whose position is defined by the position character and by using an algorithm number defined by the position character, gives the same value as that appearing on the document, then the document is authentic. As soon as information has been modified among the information taken into account in the encryption calculation, namely, either the information belonging to the truncation on the surname or the first name, or the information belonging to the date, then the result obtained does not no longer coincides with the Spy number and this makes it possible to detect a forgery as shown in Figure 2. In the case of authentic documents, the encrypted identity can be used to decrypt representative information, for example from a photo or fingerprints of the individual stored in a database file data. The device can thus display or receive by download the photo or imprint associated with the identity thus certified.

FIG. 3 represents another variant embodiment of the present invention which relates to a method of developing encrypted information from character strings (Ch1 to Ch4) and numeric value chains (Ch5 to Ch7) representing headings to be protected in order to identify falsifications of administrative documents or documents issued by public authorities. These strings (Ch1 to Ch7) are then condensed into a plurality (11 to 14) of intermediate results each comprising a number n of determined digits less than the number of characters and numerical values of the string. Then these intermediate results are transformed, by an algorithm A _x drawn randomly among several (n), into a second result (20) of n digits expressed in base 10 elaborated by a conversion matrix in a decimal base memorized by the calculation system . This second result (20) expressed in base 10 is then transformed into another result (30) said to be encrypted with ^" same number of digits, expressed in a mathematical base chosen randomly by the calculation system to obtain an encrypted identifier. The base is randomly chosen by a random draw algorithm from the calculation system and from a certain number of conversion bases available and stored by the calculation system

The alphabetic character strings and the numerical values contained in the protected headings form, after conversion into a decimal base, the intermediate results (11 to 14) which constitute the terms of the algebraic function of the algorithm A _x , drawn randomly from among several (n) , numbered from (0 to n-1), and fixed by the modulo (n) of the decimal value of a character (x), drawn randomly or chronometrically in an interval of the clock time, between two terminals by the device Calculation. For example the different algebraic functions can be constituted by the different combination of additions or subtractions between intermediate results

The result of the asymmetric mathematical function obtained by the algorithm applied to the intermediate results is then expressed in a base (y) which is also drawn randomly between two other bounds.

This result is always represented by a constant number (n) of characters, whose ranks are numbered and contain units expressed in this base (y) drawn at random.

A random key character (x) which determines the base (y) used to determine the so-called encrypted result is chronologically inserted among the characters which represent this result, at rank (q) defined by the integer quotient of the value of (x) divided by (n), by shifting by one row to the left, the characters of the result having a weight equal to or greater than the defined row.

At the end of the encryption, the random key character (x) is inserted at a predetermined rank by the designers of the calculation device or calculated

The expression 'Truncations of Alphabetical Headings' relates to long alphanumeric entry fields in which only a significant and constant number of characters from base 36 are taken into account, the memory registers concerned and not completed being set to value zero.

Depending on the nature of the complete contents of certain alphabetical headings, their decimal conversion takes the value of the total number of characters in the strings and modulo 37 from the sum of the values of the ASCII codes of the characters contained. It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered by way of illustration but may be modified in the field defined by the scope of the appended claims.

lO CD N CO O) CC _Q O O O) O). , __ _ E c o o_ cr -_ ω H-- __ι> x>. NOT

LU X

LU Z z <

Q) ω 03 _Q Ni ^* ^ ιo co ι ^ ∞ σ. o ^ o ^ ^* ^ ^ co r ^ oo σ) o ^* ^ Ni c - ^ Ln

_-J o CM C ^ m tO N OO O. - ^* Γ- -5Γ- T- ^* ^ T- T- T- OSI C \ IC | C (NJ Γ ^ ΓN1 'ΓV | OC ^ _ <__

> r ~ - so so ^ r

IΛ

O

APPENDIX 2

Base value Choice of Base (output) Value c;

0 0

1 1

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 a

11 b

12 c

13 d

14 th

15 f

16g

5 p.m.

18 i

19 ^' d

20k

21 I

22 m

. 23 n

24 0

25 P

26 q

27 r

28s

29 t

30 u

31 V

32w

33 x

34 y

35 z

36 A

37 B

38 C

39 D

40 E

41 F

42 G. 43 H 44 45 J 46 K 47 L 48 M 49 N 50 O 51 P 52 Q 53 R 54 S 55 T 56 U 57 V 58 w 59 X 60 Y 61 z 62 63

APPENDIX 3

Character Value retained Value calculated

CO 0 0.62613731 C1 38 38.194376 C2 11 11.8569374 C3 52 52.2731815 C4 16 16.6640688 C5 40 40.508199 C6 31 31.0001367

Claims

1. Method for developing encrypted information from character strings and numerical values of determined size and representing headings to be protected in order to identify falsifications of administrative documents or documents issued by public authorities, characterized in that it comprises : a step of condensing these strings into several numbers of n digits of size smaller than the number representative of the size of the strings to constitute a first set of m intermediate results of n digits; a step of transforming these m intermediate results, by an algorithm drawn randomly from among several, into a second result of n digits expressed in base 10 produced by a matrix for converting the characters of an alpha numerical base into numerical characters of a base decimal stored by a calculation system; a stage of conversion of this second result expressed in base

10 in another result said to be encrypted with the same number n of digits, expressed in a mathematical base chosen randomly by the calculation system from a determined choice of conversion bases available and stored by the calculation system, to obtain an encrypted identifier.

2. Method for developing encrypted information according to claim 1 characterized in that the alphabetic character strings and the numerical values contained in the protected headings form, after conversion to a decimal base, the terms of algebraic functions constituting each of the algorithms , one of which is drawn randomly from among several, numbered from (0 to n-1), the number of the algorithm used for the transformation being fixed by the modulo 'n) of the decimal value of the character (x), drawn randomly or chronometrically in an interval of the clock time, between two limits.

3. Method for developing encrypted information according to claim 1 or 2 characterized in that the result of the transformation by the asymmetric mathematical function of this algorithm is then expressed in a base (y) which is also drawn randomly between two other terminals.

4. Method for developing encrypted information according to one of claims 1 to 3 characterized in that this result is always represented by a constant number n of characters, the rows of which are numbered and contain units expressed in this base (y) drawn randomly.

5. Method for developing encrypted information according to one of res icationsi to 4 characterized in that the character (x) which determines the base (y) used to determine the so-called encrypted result is chronologically inserted among the characters which represent this encrypted result, at rank (q) defined by the integer quotient of the value of (x) divided by (n), shifting one row to the left, the characters of the encrypted result having a weight equal to or greater than the defined rank .

6. Method for developing encrypted information according to claim 1 characterized in that at the end of the encryption, the random key character (x) is inserted at a predetermined rank by the designers of the calculation or calculated device.

7. A method of developing encrypted information according to claim 1 characterized in that the character strings of determined size and representing headings to be protected to identify falsifications of administrative documents or issued by public authorities consist of truncations of alphabetical headings' consisting of long alphanumeric entry fields in which only a significant and constant number of characters taken into account are taken into account from a base 36 for converting these truncations into figures between 0 and 35, the memory registers concerned and not specified being set to zero.

8. Method for developing encrypted information according to claim 1 characterized in that it consists of a first truncation of the name of a being and a second truncation on a second information identifying the living being characterized in that it consists: a) in converting into integer (E2) each of the letters of the two truncations into decimal numbers; b) calculating (E3) for each numerical value representative of a character an intermediate result; c) to _. adding (E4) each of the intermediate results to obtain a result called name code and representative of coded patronymic information; d) determining (E7) a second result called Ident Spy according to a “random” algorithm drawn at random (E6) from among several; e) generating (E8) an encrypted identifier of the same size as the two truncations from the number representative of the second result obtained in the previous step, a plurality of numerical values representative of characters by a plurality of algorithms executed on this result and transforming the digital values thus obtained and between 0 and 63 into letters or numbers as output by using a conversion matrix defined by a base chosen randomly for this calculation which makes it possible to obtain the encrypted identifier.

9. Method according to claim 8, characterized in that it consists in inserting (E11) a character representative of the base number used in the preceding calculation and in inserting (E12) a second character representative of the insertion position of the first character and algorithm number used in step d.

10. Method according to claim 8, characterized in that the conversion of step a) is obtained by using a first determined base for transforming characters into figures.

11. Method according to claim 1 or 2 or 8, characterized in that each intermediate result is constituted by the numerical value corresponding to the character of a character string constituting a truncation multiplied by the value of the base at a power corresponding to the character rank value in the string.

12. Method according to claim 8, characterized in that each "random" algorithm is drawn randomly taking into account the name code, a date identifying a significant event in the living being and the algorithm number used to develop this result

13. Method according to claim 8, characterized in that the random algorithm whose number is drawn randomly to be used in step d) is determined by:

- either the addition of the code-name information and the date reduced by the representative number of factorial 8 if the random drawing defines the first algorithm;

- either the code-name minus the date to which is added the factorial of the number 8 minus the algorithm number if the random draw defined algorithm 1;

- either the name code plus the date minus twice the factorial of the number 'obtained by subtracting from 8 the algorithm number if the algorithm is 2;

- either the code-name minus the date plus twice the factorial of the number obtained by subtracting from 8 the algorithm number if the algorithm is three, ie twice factorial 5;

- either the code-name plus the date minus three times factorial from the number obtained by subtracting from 8 the algorithm number, when the algorithm is the date, that is to say 3 times factorial 4;

- either the code-name minus the date plus 3 times factorial of the number obtained by subtracting 8 the algorithm number when the algorithm is number 5, ie code-name minus the date plus 3 times factorial 3.

14. Method according to claim t ^{^} or 8, characterized in that each of the intermediate results of the algorithm defined in step b) of claim 8 or in claim 1, is obtained by multiplying the numerical value representing the character belonging to one of the truncations by the numerical value representative of the base raised to a power corresponding to the reverse order of the characters organized according to the first then the second truncations, then possibly the other truncations.

15. Device for protecting documents or verifying the authenticity of a document, characterized in that it comprises means for entering and storing character strings and numerical values of determined size and representing headings to protect to identify falsifications of administrative documents or documents issued by public authorities;

a means of executing a condensation of the character string by a first calculation algorithm on a value obtained by a conversion in a determined and fixed calculation base allowing the device to develop a plurality of stored digital values representative of the strings stored in the form of a plurality of intermediate results; means of transforming this plurality of results into a finite succession of digits by using an algorithm from a set of calculation algorithms;

- means of transforming the numerical result obtained by the use of a database. transformation drawn randomly from among several, these transformation means thus developing an encrypted identifier formed from numbers and letters and stored, means for inserting into the encrypted identifier a first character representative of an identifier of the calculation base in a position random defined by a second character inserted in a fixed position of the encrypted identifier to define on the one hand the position of the first character and on the other hand the number of the algorithm chosen randomly among several.

16. Device for protecting documents or verifying the authenticity of a document according to claim 15 characterized in that the strings of characters and numerical values consist of at least one truncation of the name and of other information identifying a being and the device comprises means of memorizing a date representative of an event related to the being.

17. Device for protecting documents or verifying the authenticity of a document, according to claim 16 characterized in that it comprises means for selecting a second calculation algorithm chosen randomly from several algorithms, this second algorithm calculation calculating, from the numerical value obtained and the date of the event, a second numerical result

18. Document protection device according to claim 15 or 17, characterized in that it comprises a printer making it possible, on the one hand, to write legible alphabetical information making it possible to identify the natural or legal person, for example the name , and a second piece of information such as, for example, the first name, identifying the being, and on the other hand, on the document, an authentication number consisting of the encrypted identifier and the two characters inserted in the encrypted identifier.

19. Protection device according to claim 15 or 17, characterized in that the device for verifying the authenticity comprises means for introducing a truncation of the identification of the natural or legal person, for example the name, and the first name identifying the being, means of entering the authentication number of the document and calculation means allowing, by an algorithm executed on a second character placed in a fixed position, to determine, firstly the position of a first representative character of the identifier of a calculation base, and secondly the number of the algorithm used in the conversion calculation to convert the alphabetical information constituted by the first and second truncations of the identifiers of the natural or legal person into an encrypted code which will be compared to the value of the encrypted code obtained from the document's authenticity number.

20. Protected document obtained by implementing the method according to one of claims 1 to 14 characterized in that it comprises, in addition to the identification information of the person in possession of the document, information calculated from a truncation determined on the identification of the natural or legal person for example, the name, the first name and the date of birth according to a calculation algorithm defined randomly among a plurality of algorithms, after conversion of the truncation in a first base the calculated information is then expressed in a randomly determined calculation base to form an encrypted identifier, a character representative of the random calculation base being inserted in the encrypted information in a random position defined by a character inserted in a determined position, this character at a determined position representing in a calculation base, a value whose quotient by a prime number provides the ^" position of the identification character of the random coding base and the remainder of the quotient the number of the algorithm drawn randomly from the plurality of algorithms.