FR2780797A1 - Method of user authentication for banking, payment or access control - Google Patents

Abstract

The authentication forms two morphological identifications (ID1, ID2), an identifier reference encrypted with a first key (CE), and a second key (CR). The second identifier (ID2) and key are used by a second device (5), to create then return an encoding table. The first device (2) encrypts the first identifier (ID1) with the encoding table to compare with the encrypted first reference code.

Description

The present invention relates generally to the authentication of a

  user to determine if he is authorized to perform a

predetermined operation.

  In order to fix the ideas, we define here terms which will be used in the following: - user: person likely to carry out a predetermined operation, such as access to a computer server, withdrawal of money from a bank, commercial transaction, access to a room or a vehicle, by

example.

  - identifier: any name, character or code that characterizes a

  given and allows to recognize it during an authentication.

  - coding table: ordered set of words, each word being an ordered series of characters from a set of characters. A table

  encoding is used to encrypt data in a conventional manner.

  - coding key: indicator or address of a coding table in

  an ordered set of coding tables.

  - authentication: series of operations aimed at ensuring identity

  of a user to determine if he is authorized to perform an operation.

  Many authentication techniques are known and used in order to reserve the possibility of carrying out a predetermined operation to a person. These techniques have in common the exchange of data between a first device available to the user and a second device, generally remote, such as a central processing computer. For example, a user provides a password to access a computer server, or provides their bank card number and handwritten signature to pay for a purchase made by mail. The password, or bank card number and signature of the user constitute identifiers. However, the risk of fraudulent use is high. Indeed, in case of loss or theft of such an identifier, another person can use it

  to perform the corresponding operation.

  To reduce this risk, morphological identifiers are now used. For example, the user must provide their fingerprints which are scanned and coded to provide a digital word which serves

  morphological identifier for a given operation.

  The morphological identifier is then stored either in the first device, or in the second device, or even in the two devices. It is then possible to fraudulently copy this identifier, and therefore to use it afterwards. In addition, in the case where the recognition of the identifier is carried out by the second device, the latter sends an authentication signal to the first device. This signal can

  be copied and then fraudulently supplied to this first device.

  To solve these problems, it has been envisaged to make the coding of the identifier and / or the coding of the data transmitted between the two devices more complex. New identification techniques

  morphological have also been considered.

  However, known techniques do not allow sufficiently reliable authentication, that is to say insensitive to a large number of fraud possibilities, to determine whether a user is authorized to

perform an operation.

  The present invention aims to remedy the drawbacks of the prior art, by providing a method of authenticating a user, using a data source specific to the user, and a first and a second processing device, characterized in that 'it comprises the steps of: - forming a first and a second morphological identifier, by the first device, - reading a first reference identifier coded by a first coding key, stored in the data source, by the first device, - reading of a second coding key stored in the data source, by the first device, - transmission of the second morphological identifier and of the second coding key to the second device, - coding of the second morphological identifier by the second coding key, by the second device, - comparison, by the second device, of the second morphological identifier coded by the second key coding with a second reference identifier coded by the second coding key and stored in the second device and, if there is identity, - transmission of a first coding table, stored in the second device, to the first device, - coding of the first morphological identifier by means of the first coding table, by the first device, comparison, by the first device, of the first morphological identifier coded by means of the first coding table with the first

  reference identifier coded by the first coding key.

  Thanks to the method according to the invention, the authentication of a user

is made reliable.

  The invention uses two morphological identifiers, each being

  treated in one or other of the devices, which secures the treatment.

  In addition, the invention uses two reference identifiers, in respective association with two coding keys. No identifier

  reference is only memorized with its coding key.

  It should be noted that the volume of data exchanged between the two devices is low, the speed and the transmission time are thus reduced, and the

  authentication processing is fast.

  According to a preferred characteristic, the training step includes reading an initial morphological identifier and then sharing the identifier

  initial morphological in the first and second morphological identifiers.

  According to another preferred characteristic, the step of transmitting the second morphological identifier and the second coding key to the second device comprises selecting a first transmission coding table from a set of transmission coding tables, coding the second morphological identifier and the second coding key by the first transmission coding table, and the transmission of the second morphological identifier and the second coding key coded by the first transmission coding table

transmission coding.

  Thus, the transmission is encrypted, which limits the risk of fraud. According to a preferred characteristic, linked to the previous one, the step of decoding, by the second device, the second morphological identifier and the second coding key coded by the first transmission coding table, prior to the coding step of the second identifier

  morphological by the second coding key.

  According to a preferred characteristic, the method further comprises the reading of an alphanumeric key, stored in the data source, by the first device, and the transmission of the alphanumeric key to the second device. According to another preferred characteristic, the method comprises the coding, by the first device, of the alphanumeric key by the first table

  transmission coding, prior to its transmission.

  According to another preferred characteristic linked to the previous one, the method comprises the decoding, by the second device, of the key

  alphanumeric coded by the first transmission coding table.

  The alphanumeric key provides access to a set of coding tables stored in the second device, and the second coding key

  allows to find a second coding table in this coding set.

  The alphanumeric key provides access to the second reference identifier coded by the second coding key, stored in the second device. According to another preferred characteristic, the transmission of the first coding table comprises the prior coding, - by the second device, of the first coding table by a second transmission coding table. This transmission is also encrypted, which limits the risk of fraud. According to another preferred characteristic, related to the previous one, the method comprises the decoding, by the first device, of the first coding table coded by the second transmission coding table, prior to the coding of the first morphological identifier by means of

the first coding table.

  Correlatively, the invention relates to a system for authenticating a user, comprising a source of data specific to the user, and a first and a second processing device, characterized in that the first device comprises: - means for formation of first and second morphological identifiers, - means for reading a first reference identifier coded by a first coding key, stored in the data source, - means for reading a second key coding stored in the data source, - means for transmitting the second morphological identifier and the second coding key to the second device, in that the second device comprises: means for coding the second morphological identifier by the second key coding, means for comparing the second morphological identifier coded by the second coding key with a second reference identifier coded by the se second coding key and stored in the second device, and, - means of transmission, if there is identity, from a first coding table, stored in the second device, to the first device, and in that the first device comprises: - means for coding the first morphological identifier (ID1) by means of the first coding table, - means for comparing the first morphological identifier coded by means of the first coding table with the first

  reference identifier coded by the first coding key.

  The invention also relates to the first device as well as the second

  device, comprising the preceding characteristics.

  The authentication system, the first and second devices

  include means for implementing the method described above.

  The advantages of the authentication system, the first and the

  second devices are similar to those of the method previously exposed.

  The characteristics and advantages of the present invention will appear more clearly on reading a preferred embodiment illustrated by the attached drawings, in which: - Figure 1 schematically shows a user authentication system according to a embodiment of the present invention, - Figures 2 to 4 show an authentication algorithm according to

  an embodiment of the invention.

  According to the embodiment chosen and shown in FIG. 1, a system for authenticating a user to determine whether he is authorized to perform a predetermined operation comprises a source 1 of identification data specific to a particular user. Source 1 is for example

  a smart card, or a magnetic card, or even a magnetic check.

  The identification data stored in source 1 are:

  - an alphanumeric key CA specific to the user.

  a first IDE / CE reference identifier coded by a first CE coding key, the IDE reference identifier being specific to the user and the CE coding key being assigned to the user. The first IDE / CE reference identifier coded by a first CE coding key is the first IDE reference identifier which has been encrypted by a TCE coding table identified by its address, or coding key, CE in a set

coding table.

  - a second coding key CR assigned to the user.

  In general, here we will call "data coded by a key" data encrypted by a coding table having this key as address

in a set.

  Source 1 includes an output connected to a first device 2 for processing and coding according to the invention. The device 2 comprises a data bus B1 to which the following circuits are connected:

  a circuit 21 for reading the data stored in the source 1.

  The circuit 21 is for example a smart card reader, or a card reader

  magnetic or magnetic check.

  a terminal 22 for entering the morphological identifier ID, by

  example a fingerprint terminal.

  a terminal 24 for entering an alphanumeric key CA, in the case where this alphanumeric key is not stored in the source 1. The terminal 24

is optional.

  - a first processing and coding circuit 23. Circuit 23 is by

  example made using a microprocessor.

  a read-only memory (ROM) 25 in which a

  processing and coding program which will be described below.

- a memory 26.

  The memory 26 comprises a random access memory (RAM) comprising registers adapted to store variables modified during execution

said program.

  The memory 26 comprises for example a hard disk for storing

  fixed data, which are as follows.

  The memory 26 stores a set ETT of transmission coding tables T1 to TN, where N is an integer. These tables are associated with the pair of devices 2 and 5 and are used to randomly encrypt the data transmissions between the two devices, as will appear in

the following.

  The memory 26 also stores a reference R2 relating to the

device 2 considered.

  A first transmit / receive circuit 3, comprising for example a modem, is also connected to the bus B1. The circuit 3 is integrated into the device 2, or is connected to the latter. The circuit 3 exchanges data with a second generally remote transmission / reception circuit 4, via a transmission medium which can be the switched telephone network, or a dedicated line, or even a radio beam. Circuits 3 and 4 carry out conventional error detection and correction operations, which will not be

described here.

  The transmit / receive circuit 4 is part of a second device for

  processing and coding 5 according to the invention, or the circuit 4 is connected to the device 5.

  The devices 2 and 5 exchange data via the circuits 3 and 4. The devices 2 and 5 can only be intended for exchanging authentication data, or as a variant be subsets of devices known per se. Depending on the applications, a given device 2 is associated with a device 5

  given, or a plurality of devices 2 is associated with a given device 5.

  For example, a plurality of users is likely to use the devices

  2, which communicate with a device 5.

  The device 5 comprises a data bus B2 to which the following circuits are connected: a second processing and coding circuit 51. The circuit 51 is by

  example made using a microprocessor.

  - a read only memory (ROM) 52 in which a

  processing and coding program which will be described below.

- a memory 53.

  The memory 53 includes a random access memory (RAM) comprising registers adapted to store variables modified during execution

said program.

  The memory 53 also includes a hard disk, for example, for storing fixed data belonging to three categories of data:

  The first category is an ETC set of coding tables.

  Each coding table has an address in the ETC set.

  The second category includes parameters relating to each of the devices 2 capable of communicating with the device 5: - the reference R2 relating to each of the devices 2, to identify this device.

  - the ETT set of transmission coding tables T1 to TN.

  The ETT set is specific to the considered pair of devices 2 and 5. This set includes the addresses of the tables T1 to TN in the ETC set, or

  alternatively includes tables Tl to TN.

  The third category includes parameters relating to each of the users likely to carry out an authentication according to the present invention: - the set of alphanumeric keys CA respectively associated

  users authorized to carry out the predetermined operation.

  a set of second IDR / CR reference identifiers respectively associated with the users authorized to perform the operation and coded by the second coding keys CR. A reference identifier IDR is specific to a user and a coding key CR is assigned to each user. The second IDR / CR reference identifier coded by the second CR coding key is the second IDR reference identifier which has been encrypted by a TCR coding table identified by its address, or coding key, CR

  in a coding table set.

  - all of the first CE coding keys respectively

  associated with users authorized to perform the operation.

  - a set ETU of user coding tables. The user coding tables are specific to the user-device pair 5. The ETU set includes the addresses of the TCE tables in the ETC set, or in a variant includes the tables. A TCE table has for address in the ETU set a first CE coding key. To implement the invention, the first device forms two morphological identifiers ID1, ID2, reads from the data source 1 a first IDE / CE reference identifier coded by a first coding key CE, and a second coding key CR , and transmits the second morphological identifier ID2 and the second coding key CR to the second

device 5.

  This code the second morphological identifier ID2 by the second coding key CR, then compares the result with a second reference identifier IDR / CR coded by the second coding key and, if there is identity, transmits a first table of TCE coding, to the first

device 2.

  The latter codes the first morphological identifier ID1 by means of the first coding table TCE, then compares the result with the

  first IDE / CE reference identifier coded by the first coding key.

  The operation of the system of FIG. 1 is now described in

  detail by means of three flowcharts shown in Figures 2, 3 and 4.

  The flow diagram of FIG. 2 comprises steps E1 to E5 stored in memory 25, which describe the operation of the first processing and coding device 2 when a user performs the operation suitable for having the data from source 1 read by the read circuit 21, by

  example by inserting his smart card in the appropriate reader.

  This first processing generally consists in transmitting a morphological identifier, called the second morphological identifier, to the

second device 5.

  Step E1 is the reading in source 1 by circuit 21 of the alphanumeric key CA, of the reference identifier IDE / CE coded by the first coding key CE, and of the second coding key CR, and the

  memorization of these parameters in memory 26.

  As a variant, the user also enters the alphanumeric key CA on

terminal 24.

  The next step E2 is the reading of the morphological identifier ID by the circuit 22. The circuit 22 is for example a circuit for taking fingerprints, which are coded in the form of a digital word. This word constitutes

  the morphological identifier ID and is stored in memory 26.

  The next step E3 is the sharing of the morphological identifier ID into two morphological identifiers ID1 and ID2. The morphological identifier ID is a digital word of predetermined length. Sharing consists, for example, in cutting the digital word into two words of predetermined length. As will appear below, the morphological identifier ID1 will be compared with the reference identifier IDE, and the morphological identifier ID2 will be compared with the identifier of

IDR reference.

  As a variant, steps E2 and E3 are replaced by the reading of two distinct morphological identifiers which will be compared respectively with the reference identifier IDE and the identifier of

IDR reference.

  In all cases, the reference identifiers are determined during an initialization during which the morphological identifiers, either resulting from the sharing of a morphological identifier, or distinct, are

  determined and stored as reference identifiers.

  The next step E4 is the random selection of a coding table Tn from the set ETT of transmission coding tables stored in memory 26, there is an integer between 1 and N. The selection of the table Tn is followed by the coding of the alphanumeric key CA, of the second morphological identifier ID2 formed in the preceding step and of the coding key CR by means of the coding table Tn. This coding is a classic encryption of

  given by the word (s) from the coding table.

  The next step E5 is the transmission of the coded data in step E4, of an indicator INn representative of the table Tn selected in step E4, and of the reference R2 from the device 2 to the second device 5, by means

of circuit 3.

  FIG. 3 represents the operations performed by the device 5 when it receives data from the device 2. This processing includes

  steps E10 to E18 stored in memory 52.

  This second processing generally consists of carrying out a test on the value of the second morphological identifier ID2, then, depending on the result of this test, whether or not to transmit a TCE coding table to the first device 2. When the test is negative, the TCE coding table is not

  transmitted, and a "dummy" key, for example negative, is transmitted in its place.

  Step E10 is the reception of data coded in step E4, from the indicator INn representative of the table T., and from the reference R2, from the

device 2.

  Step E1 is the search, by means of the reference R2, for the set of coding tables ETT relating to the device 2 considered. Then, by means of the index INn, the table Tn is sought in the set ETT of the transmission coding tables. The coding table Tn is then used to decode the coded data received in the previous step. The decoding is a decryption corresponding to the encryption of step E4. The step E1l1 results in the alphanumeric key CA, the second morphological identifier ID2 and the second coding key CR of the user. These data are stored

in memory 53.

  The next step E12 is the search for the alphanumeric key CA of the user in the list stored in memory 53. The alphanumeric key CA allows access, in memory 53, to the parameters relating to the user concerned, and in particular to the set ETU of coding tables of the user considered and to the reference identifier IDR / CR coded by the coding key CR. If the alphanumeric key CA is not found in memory 53, this means that the user is not identified by the system. Consequently, the

  processing is complete and the user is not authorized to perform the operation.

  An error message can be transmitted to device 2.

  If the alphanumeric key CA is found in the list stored in memory 53, step E12 is followed by step E13 which is the search, by means of the coding key CR, of the table TCR in the set ETU of tables

  coding of the user considered.

  The next step E14 is the coding of the second morphological identifier ID2 by the coding table TCR determined in the previous step. This step results in the second morphological identifier

  ID2 / CR encoded by the CR encoding key.

  The next step E15 is a test to determine whether the second morphological identifier ID2 / CR coded by the coding key CR obtained in the previous step is identical to the reference identifier IDR / CR coded by the coding key CR, stored in memory 53. If the answer is negative,

  The execution of the algorithm is finished.

  If the answer is positive, step E15 is followed by step E16 in which a table of searches is sought, by means of the coding key CE.

  TCE coding in the ETU set of user coding tables.

  In the next step E17, a coding table Tm, with m integer between 1 and N, is selected randomly from the set ETT of transmission coding tables stored in memory 53. The table

  TCE is then coded using the Tm table.

  The next step E18 is the transmission of the table TCE coded by the table Tm and of the index INm representative of the table Tm, to the device 2 at

circuit 4.

  FIG. 4 represents the processing carried out by the device 2 when it receives the table TCE coded by the table Tm and the indicator INm of the table

  Tm. This processing includes steps E20 to E23 stored in memory 25.

  This third processing generally consists in carrying out a test on the value of the first morphological identifier ID1 / CE coded by the first

CE coding key.

  Step E20 is the reception of the table TCE coded by the table Tm and

of the index of the table Tm.

  The next step E21 is the decoding of the table TCE using the table Tm. For this, the indicator INm first makes it possible to find the table Tm in the set ETT of coding tables for tramsmission, then the table Tm is used to decrypt the TCE table corresponding to the encryption of

step E17.

  The next step E22 is the coding of the morphological identifier ID1 by means of the table TCE. This step results in the identifier

  morphological ID1 / CE coded by the CE key.

  The next step is a test to determine whether the morphological identifier ID1 / CE coded by the key CE is equal to the reference identifier IDE / CE coded by the key CE, stored in memory 26 in step El. If the answer is negative, then the user is not authorized to perform the operation

  and the execution of the algorithm is finished.

  If the answer is positive, then user authentication is completed. The operation he wishes to accomplish is then authorized. So he is

  possible to proceed to this operation proper.

  The applications of the present invention are in particular: - cash withdrawals by bank card in a ticket office, - commercial transactions involving payment by bank card, for example via the Internet, - personal access to premises, or to a vehicle, access to data from a computer server, via a public network

or private. Of course, the present invention is in no way limited to the modes of

  realization described and represented, but includes, on the contrary,

  any variant within the reach of the skilled person.

Claims (35)

  1. Method for authenticating a user, using a source (1) of data specific to the user, and first and second processing devices (2,5), characterized in that it comprises the steps of : formation (E2, E3) of a first and a second morphological identifier (ID1, ID2), by the first device (2), - reading (El) of a first coded reference identifier (IDE / CE) by a first coding key (CE), stored in the data source (1), by the first device (2), - reading (El) of a second coding key (CR) stored in the data source ( 1), by the first device (2), transmission (E5) of the second morphological identifier (ID2) and of the second coding key (CR) to the second device (5), - coding (E14) of the second morphological identifier (ID2 ) by the second coding key (CR), by the second device (5), - comparison (E15), by the second device, of the second morphological identifier (ID2 / CR ) coded by the second coding key with a second reference identifier (IDR / CR) coded by the second coding key and stored in the second device (5) and, if there is identity, - transmission (E18) of a first coding table (TCE), stored in the second device (5), towards the first device (2), - coding (E22) of the first morphological identifier (ID1) by means of the first coding table (TCE), by the first device (2), - comparison (E23), by the first device (2), of the first morphological identifier (ID1 / CE) coded by means of the first coding table with the first reference identifier (IDE / CE ) coded by the first coding key.   2. Authentication method according to claim 1, characterized in that the training step comprises the reading (E2) of an initial morphological identifier (ID) then the sharing of the initial morphological identifier   in the first and second morphological identifiers (ID1, ID2).   3. authentication method according to claim 1 or 2, characterized in that the step of transmitting the second morphological identifier and the second coding key to the second device comprises (E4) the selection of a first coding table of transmission (Tn) in a transmission coding table set, the coding of the second morphological identifier (ID2) and of the second coding key (CR) by the first transmission coding table, and the transmission (E5) of the second morphological identifier and the second coding key coded by the   first transmission coding table.   4. Authentication method according to claim 3, characterized in that it comprises the step of decoding (El 1), by the second device (5), of the second morphological identifier (ID2) and of the second coding key (CR) coded by the first transmission coding table, prior to the coding step (E14) of the second morphological identifier (ID2) by the second coding key (CR).   5. Authentication method according to any one of   Claims 1 to 4, characterized in that it also includes the reading (El)   an alphanumeric key (CA), stored in the data source (1), by the first device (2), and the transmission (E5) of the alphanumeric key (CA) to the second device (5).   6. authentication method according to claims 3 and 5,   characterized in that it comprises the coding (E4), by the first device (2), of the alphanumeric key (CA) by the first transmission coding table   (Tn), prior to its transmission (E5).   7. authentication method according to claim 6, characterized in that it comprises the decoding (El 1), by the second device (5), of the key   alphanumeric coded by the first transmission coding table.   8. Authentication method according to any one of   claims 5 to 7, characterized in that the alphanumeric key (CA) allows   access (E13) a set of coding tables (ETU) stored in the second device (5), and in that the second coding key (CR) makes it possible to   find a second coding table (TCR) in this coding set.   9. Authentication method according to any one of   claims 5 to 8, characterized in that the alphanumeric key (CA) allows   to access (E13) the second reference identifier coded by the second key   coding (IDR / CR), stored in the second device (5).   10. Authentication method according to any one of   Claims 1 to 9, characterized in that the transmission (E18) of the first   coding table (TCE) comprises the prior coding (E17), by the second device (5), of the first coding table by a second coding table transmission (Tm).   11. Authentication method according to claim 10, characterized in that it comprises the decoding (E21), by the first device (2), of the first coding table (TCE) coded by the second transmission coding table , prior to coding (E22) of the first identifier   morphological (ID1) using the first coding table (TCE).   12. User authentication system, comprising a source (1) of data specific to the user, and first and second processing devices (2,5), characterized in that the first device (2) includes: - training means (23) of a first and a second morphological identifier (ID1, ID2), - reading means (21) of a first reference identifier (IDE / CE) coded by a first coding key (CE), stored in the data source (1), - means for reading (21) a second coding key (CR) stored in the data source (1), - means for reading transmission (3) of the second morphological identifier (ID2) and of the second coding key (CR) to the second device (5),   in that the second device (5) comprises: - means for coding (51) the second morphological identifier (ID2) by the second coding key (CR), - means for comparing (51) the second morphological identifier (ID2 / CR) coded by the second coding key with a second reference identifier (IDR / CR) coded by the second coding key and stored in the second device (5), and, - transmission means (4), if there is identity, from a first coding table (TCE), stored in the second device (5), to the first device (2), and in that the first device (2) comprises: - coding means (23) of the first morphological identifier (ID1) by means of the first coding table (TCE), - comparison means (23) of the first morphological identifier (ID1 / CE) coded by means of the first coding table with the first reference identifier (IDE / CE) coded by the first coding key. 13. Authentication system according to claim 12, characterized in that the first device (2) comprises means for reading (21) an initial morphological identifier (ID) and means for sharing (23) of the identifier initial morphological in the first and second identifiers morphological (ID1, ID2).   14. Authentication system according to claim 12 or 13, characterized in that the first device (2) comprises: - means for storing a set of transmission coding tables, - selection means (23) d '' a first transmission coding table (Tn) in the transmission coding table assembly, - coding means (23) of the second morphological identifier (ID2) and of the second coding key (CR) by the first transmission coding table, and means for transmitting (3) the second morphological identifier and the second coding key coded by the first coding table transmission coding.   15. Authentication system according to claim 14, characterized in that the second device (5) comprises means for decoding (51) the second morphological identifier (ID2) and the second coding key (CR) coded by the first transmission coding table, prior to the coding of the second morphological identifier (ID2) by the second key of coding (CR).   16. Authentication system according to any one of   Claims 12 to 15, characterized in that the first device (2) comprises   further reading means (21) of an alphanumeric key (CA), stored in the data source (1), and transmission means (3)   from the alphanumeric key (CA) to the second device (5).   17. Authentication system according to claims 14 and 16,   characterized in that the first device (2) comprises coding means (23) of the alphanumeric key (CA) by the first coding table of   transmission (Tn), prior to its transmission.   18. Authentication system according to claim 17, characterized in that the second device (5) comprises means for decoding (51) of the   alphanumeric key encoded by the first transmission coding table.   19. Authentication system according to any one of   Claims 16 to 18, characterized in that the second device (5) comprises   storage means (53) of a set of coding tables (ETU), in that the alphanumeric key (CA) allows access (E13) to the set of coding tables (ETU), and in that that the second coding key (CR) allows   find a second coding table (TCR) in this coding set.   20. Authentication system according to any of   Claims 16 to 19, characterized in that the alphanumeric key (CA)   provides access (E13) to the second reference identifier coded by the   second coding key (IDR / CR), stored in the second device (5).   21. Authentication system according to any of   Claims 12 to 20, characterized in that the second device (5) comprises   coding means (51) of the first coding table by a second transmission coding table (Tm) prior to the transmission of the first coding table (TCE).   22. Authentication system according to claim 21, characterized in that the first device (2) comprises decoding means (23) of the first coding table (TCE) coded by the second transmission coding table, prior to the coding of the first morphological identifier   (ID1) by means of the first coding table (TCE).   23. Device (2) for processing data to authenticate a user, suitable for exchanging data with another device (5), characterized in that it comprises: - training means (23) of a first and a '' a second morphological identifier (ID1, ID2), - means for reading (21) a first reference identifier (IDE / CE) coded by a first coding key (CE), stored in a data source (1 ), - means for reading (21) a second coding key (CR) stored in the data source (1), - means for transmitting (3) the second identifier   morphological (ID2) and the second coding key (CR) to the other device (5).   24. Device (2) according to claim 23, characterized in that it comprises: - means for receiving (3) a first coding table (TCE) transmitted from the other device (5), - means coding (23) of the first morphological identifier (ID1) by means of the first coding table (TCE), - comparison means (23) of the first morphological identifier (ID1 / CE) coded by means of the first coding table with the first reference identifier (IDE / CE) coded by the first coding key. 25. Device (2) according to claim 23 or 24, characterized in that it comprises means for reading (21) an initial morphological identifier (ID) and means for sharing (23) the initial morphological identifier   in the first and second morphological identifiers (ID1, ID2).   26. Device (2) according to any one of claims 23 to 25,   characterized in that it comprises: - means for storing a set of transmission coding tables, - means for selecting (23) a first transmission coding table (Tn) in the table set transmission coding, - coding means (23) of the second morphological identifier (ID2) and of the second coding key (CR) by the first transmission coding table, and - transmission means (3) of the second morphological identifier and the second coding key coded by the first table transmission coding.   27. Device (2) according to any one of claims 23 to 26,   characterized in that it further comprises means for reading (21) an alphanumeric key (CA), stored in the data source (1), and means for transmitting (3) the alphanumeric key (CA) to the other device (5).   28. Device (2) according to claims 26 and 27, characterized in that   that it comprises coding means (23) of the alphanumeric key (CA) by the first transmission coding table (Tn), prior to its transmission. 29. Device (2) according to claim 24, characterized in that it comprises means for decoding (23) the first coding table (TCE) coded by a second transmission coding table (Tm), prior to coding the first morphological identifier (ID1) using the first coding table (TCE).   30. Device (5) for processing data to authenticate a user, suitable for exchanging data with another device (2), characterized in that it comprises: - means for receiving (3) a second morphological identifier (ID2) and a second coding key (CR) transmitted by the other device (2), - coding means (51) of the second morphological identifier (ID2) by the second coding key (CR), - means for comparing (51) the second morphological identifier (ID2 / CR) coded by the second coding key with a second reference identifier (IDR / CR) coded by the second coding key and stored in the device under consideration (5) , and, - transmission means (4), if there is identity, from a first coding table (TCE), stored in the device under consideration (5), to the other device (2).   31. Device (5) according to claim 30, characterized in that it comprises means for decoding (51) the second morphological identifier (ID2) and the second coding key (CR) coded by a first coding table of transmission (Tn), prior to coding the   second morphological identifier (ID2) by the second coding key (CR).   32. Device (5) according to claim 31, characterized in that it comprises means for receiving (4) an alphanumeric key (CA) coded by the first transmission coding table and transmitted from the other device ( 2), and decoding means (51) of the coded alphanumeric key   by the first transmission coding table.   33. Device (5) according to claim 32, characterized in that it comprises storage means (53) of a set of coding table (ETU), in that the alphanumeric key (CA) allows access (E13) to the coding table set (ETU), and in that the second coding key (CR) makes it possible to find a second coding table (TCR) in this set coding.   34. Device (5) according to any one of claims 32 to 33,   characterized in that the alphanumeric key (CA) allows access (E13) to the second reference identifier coded by the second coding key   (IDR / CR), stored in the device considered (5).   35. Device (5) according to any one of claims 30 to 34,   characterized in that it comprises coding means (51) of the first coding table (TCE) by a second transmission coding table (Tm)   prior to the transmission of the first coding table (TCE).