FR2814880A1 - Electronic payment method via the internet or similar network and two user communication devices (terminal and phone) receiving verification requests from vendor - Google Patents

Abstract

A communication session is opened between first user terminal and trade server, on a first communication medium. During the session the user terminal prepares single use payment certificate, and receives, on a second terminal, phone, confidential data and transmits it to the medium. Correspondence between the confidential data transmitted to the second terminal and that transmitted by the first terminal is verified, if matched, the payment is validated. A communication session between the user and vendors server is opened, during this session the following takes place: (a) user terminal transmits user identification data; transmission to a payment server of users identity data; preparation by the user of a single use payment certificate. This includes receipt of the vendors name and amount to be paid, and display, in a window on the screen of the first user terminal, of name of vendors site and payment required; transmission by the payment server of confidential data to the users second terminal via a second communication channel on which each address is attributable to a user terminal; transmission by the first terminal of the confidential data; verification by the payment server of matching between the confidential data received by the first terminal on the first communication network with the confidential data transmitted to the second user terminal and; in case of matching, an operation of payment validation.

Description

<Desc / Clms Page number 1>

La présente invention concerne un procédé et un dispositif de certification. CERTIFICATION PROCESS AND DEVICE

The present invention relates to a certification method and device.

In particular, the present invention relates to the transmission of data online, for example over the Internet.

particulièrement vulnérable : le protocole IP, totalement décentralisé, fait circuler les "datagrammes"ou paquets sans qu'ils soient protégés. Les adresses IP elles-mêmes, gérées par les DNS (Domain Name Servers pour serveurs de noms de domaines), ne sont pas à l'abri d'actions de malveillance. Les systèmes d'exploitation ont des failles de

sécurité. D'où une liste impressionnante de menaces : - écoute de paquets ou"sniffing" ; - substitution de paquets ou"spoofing" ; - piratage de DNS ; - déni de service ; intrusions ; et - dissémination de programmes malveillants, virus et chevaux de Troie. The open nature of the Internet has increased the need for secure data transmission. Indeed, the very architecture of the Internet makes it

particularly vulnerable: the completely decentralized IP protocol circulates "datagrams" or packets without them being protected. The IP addresses themselves, managed by DNS (Domain Name Servers for domain name servers), are not immune to malicious action. Operating systems have vulnerabilities

security. Hence an impressive list of threats: - listening to packets or "sniffing"; - packet substitution or "spoofing"; - DNS hacking; - denied service ; intrusions; and - dissemination of malware, viruses and Trojans.

 Cryptology does not answer all of these questions. In cryptology, a key is inserted at the time of data encryption to ensure the confidentiality of the latter. The different security standards available, for email, for web communication sessions (SSL or Secure Socket Layer for security layer), for the IP protocol itself (IPsec), implement all the arsenal of modern methods: authentication and signature, conventional key exchange, symmetric encryption. Hundreds of millions of RSA keys have been produced.

 This poses new problems: how to manage these keys? As noted by Jacques Stern, Director of the IT Department of the Ecole Normale

<Desc / Clms Page number 2>

 Superior "it is illusory to use an RSA encryption by letting its secret keys trage on a hard disk badly protected against intrusions" (In an article published in Le Monde dated September 12, 2000). In addition, there is the question of linking an RSA public key to its legitimate owner.

- une opération de transmission de ladite partie trace depuis le système informatique émetteur au système informatique récepteur, et une opération de vérification de la correspondance de la partie de trace reçue par le système informatique récepteur avec la trace générée par le système informatique récepteur. The present invention intends to remedy all or part of these drawbacks. To this end, the present invention relates, according to a first aspect, to a certification method, characterized in that it comprises: an operation for transmitting data from a transmitting computer system to a receiving computer system, on a first communication medium , an operation for generating a trace of said data representative of said data, by the receiving computer system, an operation for transmitting part of said trace to a communication device, on a second communication medium different from the first communication medium. communication, an operation of receiving said part of the trace by the transmitting computer system,

an operation for transmitting said trace part from the sending computer system to the receiving computer system, and an operation for verifying the correspondence of the trace part received by the receiving computer system with the trace generated by the receiving computer system.

 Thanks to these provisions, the trace part is linked to said data and can be used to detect a subsequent modification of said data.

 According to particular characteristics of the process as succinctly explained above, said trace is representative of a condensate of said data.

 Thanks to these provisions, the trace part makes it possible to detect any subsequent modification of said data.

 According to particular characteristics, the method as succinctly set out above comprises an operation of transmitting an identifier of a user of the sending computer system.

 Thanks to these provisions, an authentication of the user of the sending computer system or an electronic signature can be. performed.

<Desc / Clms Page number 3>

 According to particular characteristics, the method as succinctly explained above comprises an operation of matching said identifier with an address of the communication device on the second communication medium.

 Thanks to these provisions, the address of the communication device is an address which corresponds to the user of the sending computer system.

 According to particular characteristics of the process as succinctly explained above, said trace is representative of a private key kept by the receiving computer system.

 Thanks to these provisions, the receiving computer system performs a signature of said data.

 According to particular characteristics, the method as succinctly explained above, comprises an operation of matching said identifier with said private key.

 Thanks to these provisions, the receiving computer system performs a signature of said data on behalf of the user of the sending computer system.

 According to particular characteristics, the method as succinctly explained above, comprises an operation of truncating said trace, and in that during the operation of transmitting at least part of said trace, the result of said truncation is transmitted.

 Thanks to these provisions, the part of said trace comprises fewer symbols than said trace.

 According to particular characteristics of the method as succinctly explained above, the first communication medium is the Internet.

 Thanks to these provisions, data can be transmitted from any computer system connected to the Internet.

 According to particular characteristics of the method as succinctly explained above, the second communication medium is a wireless network.

 Thanks to these provisions, authentication of the user of the sending computer system can be carried out at any location.

 According to particular characteristics of the method as succinctly explained above, during the operation of transmitting said data, an identifier of a recipient computer system is transmitted, said method comprising a

<Desc / Clms Page number 4>

 operation of transmitting said data from the receiving computer system to a recipient computer system.

 Thanks to these provisions, the receiving computer system can serve as an intermediary in a transmission between the sending computer system and the recipient computer system. It can, moreover, provide dating, notarization or hand delivery certification functions to the recipient of said data.

 According to particular characteristics, the method as succinctly described above comprises an operation of matching said data with a public key and in that during the operation of transmitting said data to said recipient computer system, said public key is transmitted.

 Thanks to these provisions, the recipient of said data can verify the identity of the sender of said data, by implementing the public key.

 According to particular characteristics, the method as succinctly described above comprises an operation for generating confidential information by the receiving computer system and an operation for transmitting confidential information to a communication device to a second communication device. on the second communication medium, by the receiving computer system, an operation for receiving said confidential information by the receiving computer system, on the first communication means and an operation for verifying correspondence between the confidential information transmitted by the computer system receiver with confidential information received by the receiving computer system.

 Thanks to these provisions, the recipient of said data is authenticated.

 The present invention also relates to a certification device, characterized in that it comprises: a means of transmitting data from a transmitting computer system to a receiving computer system, on a first communication medium, - a means of generating a trace of said data representative of said data, by the receiving computer system, - a means of transmitting at least part of said trace to a communication device, on a second communication medium different from the first communication medium, - a means of reception of said trace by the transmitting computer system,

<Desc / Clms Page number 5>

 a means of transmitting said trace from the sending computer system to the receiving computer system, and a means of verifying the correspondence of the trace received by the receiving computer system and of the trace generated by the receiving computer system.

 The particular characteristics and the advantages of said device correspond to the particular characteristics and advantages of the process as succinctly explained above.

 Other advantages, aims and characteristics of the present invention will emerge from the description which follows, given with reference to the appended drawing in which: FIG. 1 represents a succession of operations carried out by a user terminal and a certification server, in a particular embodiment of the present invention; - Figure 2 shows a succession of operations performed by a user terminal and the certification server, in another particular embodiment of the present invention; - Figure 3 shows a succession of operations performed by a user terminal and the certification server, in another particular embodiment of the present invention; and - Figure 4 shows a flowchart of implementation of another embodiment of the present invention.

 In Figure 1 are shown a user station or sending computer system 100, an Internet application 110, a clean room 120, a storage memory 130, a second communication network 140 and a receiver 150 on the second communication network 140. The room blanche 120 includes a firewall protection 160, a security server 170 and a certificate generator 180. The operations carried out in the particular embodiment illustrated in FIG. 1 are represented in rectangles and numbered by 1 to 12. The Internet application 110 and the clean room 120 are jointly called the receiving computer system.

 The user station 100 is, for example, a personal computer (PC), a network computer (NC) or a personal digital assistant (in English Personal Digital Assistant or PDA). The user station 100 is provided with remote communication software for implementing the Internet application 110, jointly

<Desc / Clms Page number 6>

 with the security server 170. This remote communication software can be a navigation software or an electronic mail software. for example.

 The Internet application 110 allows communication between the user station 100 and the security server 170 and the transmission of data from the user station 100 to the storage memory 130, for example via the security server 170. The room blanche 120 is a space protected against any physical intrusion, such as a bank vault. The storage memory 130 is a memory adapted to store data for a long period, which exceeds one year.

récepteurs alphanumériques communément appelés"pageurs". Le deuxième réseau 140 est appelé"deuxième"par comparaison avec le réseau Internet, que l'on nomme aussi "premier"réseau dans la suite de la présente demande de brevet. Le deuxième réseau 140 est adapté à transmettre une clé ou certificat depuis le serveur de sécurité 170 jusqu'au récepteur 150. Le récepteur 150 sur le deuxième réseau 140 peut, selon le type de deuxième réseau 140, être un téléphone mobile, un pageur ou un récepteur quelconque. The second communication network 140 is. for example, a telephone network and, even more particularly a mobile telephone network or

alphanumeric receivers commonly called "pagers". The second network 140 is called "second" by comparison with the Internet, which is also called "first" network in the remainder of this patent application. The second network 140 is suitable for transmitting a key or certificate from the security server 170 to the receiver 150. The receiver 150 on the second network 140 can, depending on the type of second network 140, be a mobile phone, a pager or any receiver.

The receiver 150 allows the user of the user station 100 to take cognizance of information transmitted by the security server 170.

 The firewall protection 160 is of the hardware and / or software type and prohibits any software intrusion into the security server 170. The security server 170 is a computer server of known type. Finally, the certificate generator 180 is suitable for generating disposable certificates, for example of the type conforming to the X509-V3 standard.

 The user station 100 and the security server 170 are jointly adapted to implement the operations indicated below. For example, the security server 170 is suitable for providing application routines or "applets" to the user station 100.

 At the start of the certification process, it is assumed that data is to be transmitted in a certified and signed manner from the user station 100 to the storage memory 130. The user of the user station 100 connects to the security server 120 to launch the certification process.

 During operation 1, after identification of the user on the user station 100, the Internet application 110 downloads a certified application routine signed in the user station 100. It is observed that the application routine in question

<Desc / Clms Page number 7>

 can only be downloaded in the case where a copy of this routine is not already installed in the user station 100. This particular characteristic makes it possible to make the certification process object of the present invention portable, without slowing down this process in the case where the user successively implements the same user station 100, for several data certifications. During operation 2, the certificate generator 180 generates a disposable certificate, for example in the form of a private key conforming to the X509-V3 standard. For example, the disposable certificate is generated randomly by the generator 180.

 During operation 3, the security server 170 transmits the disposable certificate to the user station 100. During operation 4, the user station 100 implements the application routine downloaded during operation 1 to obtain a trace of the data to be transmitted, called condensâ (in English "hash"), a trace which depends on the disposable certificate generated during operation 2 and on the data to be transmitted and which allows the detection of any subsequent modification of the data to be transmitted.

 During operation 5, the data to be transmitted and the condensa are downloaded from the user station 100 to the Internet application 110. In addition, the coordinates of each recipient of the data to be transmitted is transmitted by the user station 100 to the Internet application 110. These contact details can take the form of an e-mail address, a telephone number or any other type of information enabling each recipient of the data to be transmitted to be contacted . During operation 6, the integrity of the data to be transmitted is checked, using the disposable key generated during operation 2 and the condensed.

 It is observed that at the end of operation 6, a copy of the data to be transmitted has been made from the user station 100 in the Internet application 110 and that this copy is certified as being true to the original thanks to the implementation a disposable key. To prevent the disposable certificate from being reused, during operation 10, the disposable certificate is revoked, that is to say that it becomes unusable for certifying data.

certificat à durée de vie très courte, préférentiellement inférieure à une heure. Dans cette variante, l'opération 10 n'est pas exécutée puisqu'au delà de la durée de vie du certificat jetable, ce certificat n'est pas utilisable pour certifier des données. As a variant, the disposable certificate generated during operation 2 is a

certificate with a very short lifespan, preferably less than one hour. In this variant, operation 10 is not executed since beyond the lifetime of the disposable certificate, this certificate cannot be used to certify data.

 Operations 7 and 8 correspond to an example of a signature which can be used in combination with operations 1 to 6 above. During operation 7, a secret seal is generated and transmitted, via the second network 140, to the

<Desc / Clms Page number 8>

 receiver 150. The address of receiver 150 on the second network is determined by matching the identifier of the user transmitted during operation 1 with said address, in a correspondence table. Preferably, the secret seal is calculated on the signature elements of the document. Preferably, the secret seal depends on the data to be transmitted, their number, their content, the date and time of the generation of the secret seal, the private key of the data sender determined in correspondence with the identifier of the user transmitted during operation 1, of the internet address ("IP address") of the user station 100 and / or of a number of the internet session during which the data is transmitted. According to an example of implementation of operation 7, the secret seal is obtained by calculating a condensed data to be transmitted, for example in the form of a sequence of twenty symbols, encrypting this condensed by the key the user of the user station 100, and of extracting part of the result of this encryption, for example eight symbols out of twenty.

 The reader may refer to FIG. 4 and / or to the patent application PCT / FR98 / 02348 for better knowledge of examples of steps implemented during operations 7 and 8. During operation 8, l the common user of the user station 100 and of the receiver 150 enters the secret seal and this secret seal is transmitted to the security server 170 where the seal is verified, operation 9.

 As a variant, operations 7 to 9 are replaced by a signature operation based on the use of a memory card ("smart card") or a biometric measurement.

 At the end of operation 8, the data transmitted is therefore certified to be intact and signed by the user who transmits it. Operation 9 consists of substituting a so-called PKI signature (for Public Key Infrastructure, or public key infrastructure) for the signature made during operations 7 and 8.

 During operation 9, the data transmitted is signed with the private key of the user who transmitted it (known as the "signatory" of the data).

 Finally, during operation 11, the data transmitted, certified and signed by private key are transmitted to the storage memory 130 with a date in such a way that they are time-stamped, archived and notarized.

 In an application of the present invention to hand delivery of the data transmitted, a recipient is, following operation 11, informed of the availability of the data to be transmitted and of operations similar to the operations set out above. above are implemented to make a certified copy on

<Desc / Clms Page number 9>

 the user station of the recipient after having collected a signature from him. For example, a signature as set out in patent application PCT / FR98 / 02348 can again be used to authenticate the recipient. An example of a succession of operations implemented for this hand delivery is given in FIG. 2.

 In FIG. 2 are shown a recipient user station or recipient computer system 200, the Internet application 110, the clean room 120, the storage memory 130, the second communication network 140 and a receiver 250 on the second communication network 140. The operations carried out in the particular embodiment illustrated in FIG. 2 are represented in rectangles and numbered from 13 to 25. These operations can follow operations 1 to 12 illustrated in FIG. 1 and carried out in relation to a user station 100 generally different from the user station 200.

 The destination user station 200 is, for example, a personal computer (PC), a network computer (NC) or a personal digital assistant (in English Personal Digital Assistant or PDA). The destination user station 200 is provided with remote communication software for implementing the Internet application 110, together with the security server 170. This remote communication software can be a navigation software or a mail software electronics, for example.

 The Internet application 110 allows communication between the user station 200 and the security server 170 and the transmission of data from the user station 200 to the storage memory 130, for example via the security server 170.

 The receiver 250 on the second network 140 can, depending on the type of second network 140, be a mobile phone, a pager or any receiver.

The receiver 250 allows the user of the destination user station 200 to take cognizance of information transmitted by the security server 170.

 The destination user station 200 and the security server 170 are jointly adapted to implement the operations indicated below. For example, the security server 170 is suitable for providing application routines or "applets" to the destination user station 200.

<Desc / Clms Page number 10>

 At the start of the certification process, it is assumed that data is to be transmitted in a certified and signed manner from the storage memory 130 to the destination user station 200.

 The user of the destination user station 200 initially connects to the first network, for example to consult electronic mails.

 During operation 13, the Internet application 110 sends to the destination user station 200 an electronic mail (e-mail) which indicates that information is made available to the user of the station 200.

 During operation 14, the user accesses the internal application 110 by selecting his Internet address. During operation 15, the Internet application 110 downloads a certified application routine to the destination user station 200.

It is observed that the application routine in question can only be downloaded in the case where a copy of this routine is not already installed in the user station 200. This particular characteristic makes it possible to make the certification process which is the subject of this present portable. invention, without slowing down this process in the case where the user successively implements the same destination user station 200, to receive several data sets. It is observed that the application routines downloaded during operations 1 and 15 may be identical to allow on the one hand the transmission of data to the memory 130 and, on the other hand, to receive data from this memory.

 The operations 16 and 17 correspond to an example of signature which can be used in combination with the operations 13 to 15 above. During operation 16, a secret seal is generated and transmitted, via the second network 140, to the receiver 250. Preferably, the secret seal is calculated on the signature elements of the document. Preferably, the secret seal depends on the data to be transmitted, their number, their content, the date and time of the generation of the seal, and / or a number of the Internet session during which the data are transmitted. The reader can refer to the patent application PCT / FR98 / 02348 for a better understanding of examples of steps implemented during operations 16 and 17. During operation 17, the common user of the destination user station 200 and the receiver 250 enters the secret seal on the destination user station 200 and this secret seal is transmitted to the security server 170 where the seal is verified. At the end of operation 17, the data transmitted is therefore certified to be intact and signed by the user who transmits it.

<Desc / Clms Page number 11>

 As a variant, operations 16 and 17 are replaced by a signature operation based on the use of a memory card ("smart card") or a biometric measurement.

 During operation 18, the certificate generator 180 generates a withdrawal certificate, for example in the form of a key conforming to standard X509-V3.

The withdrawal certificate contains the public key of the user of the user station 100. During operation 19, the security server 170 transmits the withdrawal certificate to the destination user station 200. During operation 20, l application 110 determines a summary of the data to be transmitted, which depends on the withdrawal certificate generated during operation 18 and on the data to be transmitted and which allows the detection of any subsequent modification of the data to be transmitted.

 During operation 21, the data to be transmitted and the condensa are downloaded from the Internet application 110 to the destination user station 200. During operation 22, the integrity of the data to be transmitted is checked, in using the public key contained in the withdrawal certificate generated during operation 18 and the condensed.

 It is observed that at the end of operation 22, a copy of the data to be transmitted has been made from the storage memory 130 to the destination user station 200 and that this copy is certified as being true to the original by putting using a disposable key. During operation 23, an integrity acknowledgment is transmitted from the destination user terminal 200 to the security server 170. This integrity acknowledgment indicates that the data to be transmitted has been transmitted to the destination user terminal 200 with integrity, that is to say that the data to be transmitted have not been modified after operation 20.

 During operation 24, a trace of the transmission of the data to the recipient user is certified and stored in the storage memory 130. This date is associated with the transmitted data and is thus time-stamped, archived and notarized.

During operation 25, the security server makes available to the sender of the data transmitted an acknowledgment of receipt which informs it that the data which it has transmitted during operation 4 have been received by the 'one of their recipient. It is observed that an acknowledgment of receipt is transmitted to the data sender for each of the recipients of the data.

 In Figure 3 are shown the user station or sending computer system 100, an Internet application 310, the clean room 120, the storage memory

<Desc / Clms Page number 12>

 130, the second communication network 140 and the receiver 150 on the second communication network 140. The operations carried out in the particular embodiment illustrated in FIG. 3 are represented in rectangles and numbered from 31 to 42. The Internet application 310 and the clean room are jointly called the receiving computer system.

 The user station 100 and the security server 170 are jointly adapted to implement the operations 31 to 42 indicated below. At the start of the certification process, it is assumed that several data sets are to be transmitted in a certified and signed manner from the user station 100 to the storage memory 130. The user of the user station 100 connects to the security server 120 to start the certification process.

 During operation 31, after identification of the user of the user station 100, the Internet application 310 downloads a certified application routine to the user station 100. It is observed that the application routine in question may only be downloaded in the case where a copy of this routine is not already installed in the user station 100. This particular characteristic makes it possible to make the certification process object of the present invention portable, without slowing down this process in the case where the user successively puts uses the same user station 100, for several data certifications. During operation 32, the certificate generator 180 generates a disposable certificate, for example in the form of a private key conforming to the X509-V3 standard. For example, the disposable certificate is generated randomly by the generator 180.

 During operation 33, the security server 170 transmits the disposable certificate to the user station 100. During operation 34, the user explicitly selects each of the data sets to be transmitted. For example, the user of the user station 100 selects, one by one, files to be transmitted, each file constituting a set of data to be transmitted.

 Still during operation 34, the user station 100 implements the application routine downloaded during operation 31 to obtain a summary of each of the data sets to be transmitted, which depends on the disposable certificate generated during operation 32 and data from said set. Each condensâ allows the detection of any subsequent modification of a set of data to be transmitted.

 During operation 35, the data sets to be transmitted and the condensates are downloaded from the user station 100 to the Internet application

<Desc / Clms Page number 13>

310. De plus, des coordonnées de chaque destinataire de chaque ensemble de données à transmettre est transmis par le poste utilisateur 100 à l'application Internet 110. Ces coordonnées peuvent prendre la forme d'adresse de courrier électronique (en anglais"e- mail"), de numéro de téléphone ou de tout autre type d'information permettant de contacter chaque destinataire des données à transmettre. Au cours de l'opération 36. l'intégrité des ensembles de données à transmettre est vérifiée, en mettant en oeuvre la clé jetable générée au cours de l'opération 32 et les condensâ.

310. In addition, the coordinates of each recipient of each set of data to be transmitted is transmitted by the user station 100 to the Internet application 110. These coordinates can take the form of e-mail address (in English "e-mail "), telephone number or any other type of information allowing contact with each recipient of the data to be transmitted. During operation 36. the integrity of the data sets to be transmitted is checked, using the disposable key generated during operation 32 and condensing them.

données à transmettre à été faite depuis le poste utilisateur 100 dans l'application Internet 310 et que cette copie des ensembles de données est certifiée conforme à l'original grâce à la mise en oeuvre d'une clé jetable. Pour éviter que le certificat jetable soit réutilisé, au cours de l'opération 40, le certificat jetable est révoqué, c'est-à-dire qu'il devient inutilisable pour certifier des ensembles de données. It is observed that at the end of operation 36, a copy of the sets of

data to be transmitted has been made from the user station 100 in the Internet application 310 and that this copy of the data sets is certified true to the original thanks to the use of a disposable key. To prevent the disposable certificate from being reused, during operation 40, the disposable certificate is revoked, that is to say it becomes unusable for certifying data sets.

 As a variant, the disposable certificate generated during operation 32 is a certificate with a very short lifespan, preferably less than one hour. In this variant, operation 10 is not executed since beyond the lifetime of the disposable certificate, this certificate cannot be used to certify data.

 The operations 37 and 38 correspond to an example of signature which can be used in combination with the operations 31 to 36 above. During operation 37, a secret seal is generated and transmitted, via the second network 140, to the receiver 150. The address of the receiver 150 on the second network is determined by matching the identifier of the user transmitted during operation 31 with said address, in a correspondence table. Preferably, the secret seal depends on the data to be transmitted, their number, their content, the date and time of the generation of the secret seal, the private key of the data sender determined in correspondence with the identifier of the user transmitted during operation 1, of the internet address ("IP address") of the user station 100 and / or of a number of the internet session during which the data is transmitted. According to an example of implementation of operation 7, the secret seal is obtained by calculating a condensed data to be transmitted, for example in the form of a sequence of 20 symbols, encrypting this condensed by the key the user of the user station 100 and extracting part of the result of this encryption.

 The reader can refer to FIG. 4 and / or to the patent application PCT / FR98 / 02348 for better knowing examples of steps implemented during

<Desc / Clms Page number 14>

 of operations 37 and 38. During operation 38, the common user of the user station 100 and of the receiver 150 enters the secret seal and this secret seal is transmitted to the security server 170 where the seal is verified, operation 39.

 As a variant, operations 37 to 39 are replaced by a signature operation based on the use of a memory card ("smart card") or a biometric measurement.

 At the end of operation 38, the transmitted data sets are therefore certified to be intact and signed by the user who transmits them. Operation 39 consists in substituting a so-called PKI signature (for Public Key Infrastructure) for the signature made during operations 37 and 38.

 During operation 39, the transmitted data sets are signed with the private key of the user who transmitted them (known as the "signatory" of the data).

 Finally, during operation 41, the transmitted data sets. certified and signed by private key are transmitted to the storage memory 130 with a date in such a way that they are time-stamped. archived and notarized.

 In an application of the present invention to a personal delivery of the transmitted data sets, for each data set to be transmitted, a recipient is, following operation 41, informed of the availability of the set of data to be transmitted and operations similar to the operations set out above are implemented to make a certified copy on the user station of the recipient after having collected a signature from him. An example of a succession of operations implemented for this hand delivery is given in FIG. 2.

 FIG. 4 represents a flow diagram of implementation of another embodiment of the present invention. In the leftmost column of FIG. 4 are represented operations relating to a so-called "transmitting" computer system 401 implementing a first communication medium. In the column to the right of the leftmost column are shown operations relating to a first communication device 402 implementing a second communication medium. In the central column are represented operations relating to a computer system 403 known as "receiver" implementing the first, the second, a third and a fourth communication medium. In the rightmost column are shown operations relating to a computer system 405 called "recipient" implementing the third communication medium. Finally, in the

<Desc / Clms Page number 15>

 column between the central column and the rightmost column, are shown operations relating to a second communication device 404 implementing the fourth communication medium.

 The sending computer system 401 and the first communication device 402 are used by a user who wishes to transmit data to a recipient user who uses the second communication device 404 and the recipient computer system 405. For example, the sending computer system 401 is a personal computer, or a network computer, connected to the Internet.

For example, the destination computer system 405 is another personal computer, or another network computer, connected to the Internet. The first and third networks can be confused or different. The first and third networks can thus be the Internet.

 The second and fourth networks may, in particular be non-wired networks. For example, the first communication device 402 is a mobile phone or a pager. For example, the second communication device 404 is a mobile phone or a pager. The second and fourth networks can be confused or different. However, the first and second communication media are different. In addition, the third and the fourth communication medium are different. Preferentially. the communication devices 401 and 404 have unique addresses on the second and the fourth communication network, respectively.

 According to an exemplary embodiment. the receiving computer system 403 is a network server connected to network interfaces to communicate on the first to fourth networks. In the following description of FIG. 4, it is considered that the receiving computer system 403 retains the means necessary to obtain a private key and a public key from a user of the sending computer system 401, the address of the first communication device. 402 on the second communication medium, and the address of the second communication device 404 on the fourth communication medium.

 For example, the receiving computer system 403 stores in memory:

<Desc / Clms Page number 16>

 the private key and the public key of each user capable of implementing the method described in FIG. 4, a table of correspondence between user identifiers and addresses on the second communication medium, and - a means of interrogating a database keeping a correspondence table between identifiers of recipient users and addresses on the fourth communication medium.

 According to a variant, the address of the recipient user on the fourth network is obtained from the sending user, as in the case illustrated in FIG. 4.

 The start-up and initialization operations and the shutdown operations of the computer systems and of the communication devices are not shown in FIG. 4.

 During an operation 408, the sending computer system 401 connects to the receiving computer system 403, via the first communication medium. During an operation 409, the receiving computer system 403 transmits to the sending computer system 401 a program making it possible to determine a condensate of data to be transmitted.

 During transmission operations 410 and 411, the transmitting computer system 401 transmits to the receiving computer system 403, on the first communication medium: - data to be transmitted to the destination computer system 405, - a condensate of the data to be transmitted determined with the program transmitted during operation 409, - an identifier of a user of the sending computer system 401 or an identifier of the sending computer system 401, and - an identifier of the recipient computer system 405 and an address of the second means of communication 404 .

 During a matching operation 412, the receiving computer system 403 matches said identifier with a private key of the user of the sending computer system 401.

 During a generation operation 413, the receiving computer system 403 generates a trace of the data to be transmitted. The trace is representative of the data to be transmitted. Preferably, said trace is representative of a condensed

<Desc / Clms Page number 17>

 said data to be transmitted and the private key kept by the receiving computer system 403. For example, said trace is obtained by an operation of signing the condensed by the private key of the user of the sending computer system 401. Thus, said trace is linked to said data and any subsequent modification of said data is detectable. In addition, the source of said data is thus authenticated by the user's private key.

 During a matching operation 414, the identifier of the user of the sending computer system 401 is matched with an address of the communication device 402 on the second communication medium.

 During a transmission operation 415 of part of said trace, at least part of the trace determined during operation 413 is transmitted by the receiving computer system 403 to the first communication device 402. For example, the transmission operation 415 comprises during the truncation operation 416 during which the trace determined during the operation 413 is truncated and the result of said truncation is transmitted to the first communication device 402.

 During a reception operation 417, said trace part is received by the transmitting computer system 401. For example, the first communication device 402 displays said trace on a display screen and the user of the first communication device 402 types said trace on a keyboard of the sending computer system 401. According to variants, the sending user dictates said part of the trace which is recognized by a voice recognition system or the sending user provides said part of the trace to the sending computer system 401 through any user interface.

 During a transmission operation of said trace part 418, said trace part is transmitted from the sending computer system 401 to the receiving computer system 403.

 During a verification operation 419, the receiving computer system checks the correspondence of the part of the trace received by the receiving computer system 403 with the trace generated by the receiving computer system 403. The correspondence is, in the example of the Figure 4, an equality between the transmitted trace and the received trace. If there is no correspondence, the receiving computer system indicates to the sending user that it has not been authenticated, by means of the first communication medium or by means of the second communication medium and invites the sender user to start again the operations illustrated in figure 4.

<Desc / Clms Page number 18>

 If there is a match, during a matching operation 420, the receiving computer system 403 matches said data with a public key of the sending user.

 During a communication operation 421, the receiving computer system 403 transmits a message, for example an electronic mail, to the recipient user inviting him to connect via the third communication medium to the receiving computer system 403.

 During a connection operation 422, the recipient user makes the connection between the recipient computer system 405 and the receiver computer system 403.

 During an operation for generating confidential information 423, the receiving computer system 403 generates confidential information. During a transmission operation 424, the receiving device 403 transmits said confidential information to the second communication device 404, via the second communication medium.

 During a reception operation 425, said confidential information is received by the recipient computer system 405. For example, the second communication device 404 displays said confidential information on a display screen and the user of the second communication device 404 types said confidential information on a keyboard of the recipient computer system 405. According to variants, the recipient user dictates said confidential information which is recognized by a voice recognition system or the recipient user supplies said confidential information to the recipient computer system 405 by through any user interface.

 During a transmission operation of said confidential information 426, said confidential information is transmitted from the recipient computer system 405 to the receiver computer system 403.

 During a correspondence verification operation 427, the receiving computer system 403 checks the correspondence between the confidential information transmitted by the receiving computer system 403 and the confidential information received by the receiving computer system 403. If there is no there is no correspondence, the receiving computer device 403 indicates to the recipient user that it has not been authenticated, by means of the third or fourth communication medium and invites him to repeat the operations 422 and following.

<Desc / Clms Page number 19>

 When there is correspondence, during a data transmission operation to the recipient computer system 428, the receiver computer system 403 transmits to the recipient computer system 405 the data to be transmitted.

- la trace desdites données à transmettre calculée au cours de l'opération, et un programme permettant de déterminer ledit condensâ desdites données. Preferably, the computer system 403 transmits jointly to the data to be transmitted: a public key of the sending user to the recipient computer system
405

the trace of said data to be transmitted calculated during the operation, and a program making it possible to determine said condensate of said data.

 During an operation 429, the recipient computer system determines the codens of said data to be transmitted calculated during operation 413 and uses the public key received during operation 428 to determine the condensed of said data which was used to generate the trace transmitted during operation 428.

When the two condensâ are equal, the recipient user has the assurance that it is the sending user who transmitted the data to be transmitted and that these data have not been modified since they were transmitted by the sending user.

 According to variants, the operations presented in FIGS. 1, 2 or 3 and the operations presented in FIG. 4 are combined in such a way that, in these variants, a disposable key is used for the transmission of data from one computer system to another. and a trace which depends on the data to be transmitted and, possibly on a private key of the sending user, is implemented.

Claims (13)

 1. Certification method, characterized in that it comprises: - an operation for transmitting (4, 5) data from a transmitting computer system (100) to a receiving computer system (130), on a first communication medium, an operation for generating (7) a trace of said data representative of said data, by the receiving computer system, - an operation for transmitting (7) part of said trace to a communication device, on a second communication medium different from the first communication medium, an operation for receiving (8) said trace part by the transmitting computer system,

 an operation for transmitting (8) said trace part from the sending computer system to the receiving computer system, and an operation for verifying (9) the correspondence of the trace part received by the receiving computer system with the trace generated by the system computer receiver.  2. Method according to claim 1, characterized in that, during said operation of generating said trace, said trace is representative of a condensed of said data.  3. Method according to any one of claims 1 or 2, characterized in that it comprises an operation of transmission (1) of an identifier of a user of the sending computer system.  4. Method according to claim 3, characterized in that it comprises a matching operation (7) of said identifier with an address of the communication device on the second communication medium.  5. Method according to any one of claims 1 to 4, characterized in that, during said operation for generating said trace, said trace is representative of a private key kept by the receiving computer system.  6. Method according to any one of claims 3 or 4 and according to claim 5, characterized in that it comprises a matching operation (7) of said identifier with said private key. <Desc / Clms Page number 21> 7. Method according to any one of claims 1 to 6, characterized in that it comprises an operation of truncation (7) of said trace, and in that during the operation of transmission of a part of said trace, the result of said truncation is transmitted.  8. Method according to any one of claims 1 to 7, characterized in that the first communication medium is the Internet.  9. Method according to any one of claims 1 to 8, characterized in that the second communication medium is a wireless network.  10. Method according to any one of claims 1 to 9, characterized in that. during the operation of transmitting said data (5), an identifier of a recipient computer system is transmitted, said method comprising an operation of transmitting said data from the receiving computer system to a recipient computer system.  11. Method according to claim 10, characterized in that it comprises an operation of matching said data with a public key and in that during the operation of transmitting said data to said recipient computer system, said public key is transmitted.  12. Method according to any one of claims 10 or 11, characterized in that it comprises an operation for generating confidential information by the receiving computer system and an operation for transmitting information to a second device for communicating confidential to a communication device on the second communication medium, by the receiving computer system, an operation for receiving said confidential information by the receiving computer system, on the first communication means and an operation for verifying correspondence between the information confidential transmitted by the receiving computer system with the confidential information received by the receiving computer system.  13. Certification device, characterized in that it comprises: a means of transmitting data from a transmitting computer system to a receiving computer system, on a first communication medium,

 means for generating a trace of said data representative of said data, by the receiving computer system, means for transmitting at least part of said trace to a communication device, on a second communication medium different from the first communication medium communication, <Desc / Clms Page number 22>  means for receiving said trace by the sending computer system, means for transmitting said trace from the sending computer system to the receiving computer system, and means for verifying the correspondence of the trace received by the receiving computer system and the trace generated by the receiving computer system.