FR2823930A1 - 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

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  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, by

example on the Internet.

  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 IP protocol, completely decentralized, 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 security vulnerabilities. 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 in order to ensure the confidentiality of the latter. The various 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.

  I1 then poses new problems: how to manage these keys? As noted by Jacques Stern, Director of the IT Department of Eco le Normale

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  Superior "it is illusory to use an RSA encryption by letting your secret keys slip on a hard disk badly protected against intrusions" (In an article published in Le Monde dated September 12, 2000). Furthermore the question arises of tying a key

  public RSA to its rightful owner.

  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 process, characterized in that it comprises: an operation for transmitting data from a transmitting computer system to a receiving computer system, on a first medium of 1 0 communication, - 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, - an operation for receiving said trace part by the sending 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 part of the trace received by the receiving computer system with the tra this system generated

computer receiver.

  Thanks to these provisions, the trace part is linked to said data and can

  serve to detect a subsequent modification of said data.

  According to particular characteristics of the process such as succinctly

  exposed 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, authentication of the system user

  computer or an electronic signature can be made.

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  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 a

  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 system

computer receiver.

  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 set out 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 portion of said trace comprises less than

symbols that said trace.

  According to particular characteristics of the process such as succinctly

  exposed 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 process such as succinctly

  exposed above, the second communication medium is a wireless network.

  Thanks to these provisions, the authentication of the system user

  sender IT can be done anywhere.

  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

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  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. I1 can, moreover, provide functions of dating,

  notarization or hand delivery certification 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 system. receiving computer with confidential information received by the system

computer receiver.

  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 receipt of said trace by the transmitting computer system,

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  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 advantages of said device correspond to the particular characteristics and advantages of the process such as

succinctly set out above.

  Other advantages, aims and characteristics of the present invention

  will emerge from the description which follows made with reference to the appended drawing in which:

  - Figure 1 shows a succession of operations performed 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 mode of

  realization 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 1 10 and the clean room 120 are jointly called the receiving computer system. User station 100 is. for example, a personal computer (PC), a network computer (C) or a personal digital assistant (Personal Digital Assistant or PDA). The user station 100 is provided with remote corumunication software for implementing the Internet application 110, jointly

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  with the security server 170. This remote communication software can be a

  navigation software or email 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. The second communication network 140 is. for example, a telephone network and, even more particularly a network of mobile telephones or of alphanumeric receivers commonly called "pagers". The second network 140 is called "second" by comparison with the Internet network, which is also called "first" network in the rest 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 telephone, any pager or any receiver.

  The receiver 150 allows the user of the user station 100 to take cognizance of

  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 adapted to

  generate disposable certificates, for example of type conforming to standard X509-V3.

  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 'to the storage memory 130. The user of the user station 100 connects to the server of

  120 security to start 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

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  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 portable the certification process object of the present invention, 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 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 1 10. 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 may 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 contacted at pass. During operation 6, the integrity of the data to be transmitted is checked, in

  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, i.e. it becomes unusable for certifying data.

  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 certificate

  disposable, 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 sccau is generated and transmitted, via the second network 140, to the

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  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. Primarily, the secret seal is calculated on the signature elements of the document. Primarily, 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 calculation of a condensa of the data to be transmitted, for example in the form of a sequence of twenty symbols, of encryption of this condensa by the key the user of user station 100, and extraction

  part of the result of this encryption, for example eight symbols out of twenty.

  The reader can refer to FIG. 4 and / or to patent application PCT / FR98 / 02348 to better know examples of steps implemented during operations 7 and 8. During operation 8 , the common user of the user station and of the receiver 150 enters the secret seal and this secret seal is transmitted to the server of

  security 170 o 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 in substituting a so-called PKI (Public Key Infrastructure) signature for

  the signature made during operations 7 and 8.

  During operation 9, the transmitted data are signed with the key

  privacy 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 of such

  so that they are time-stamped, archived and notarized.

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

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  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 destination 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, together with the security server 170. This remote communication software can be a navigation software or a mail software electronic, by

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 telephone, a pager or any receiver.

  The receiver 250 allows the user of the destination user station 200 to take

  knowledge 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" at the receiving user station 200.

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  At the start of the certification process, it is assumed that data is to be transmitted in a certified and signce manner from the storage memory 130 up to

recipient user extension 200.

  The user of the destination user station 200 initially connects to the first network, for example to consult electronic mails. During the operation 13, the Internet application 110 sends to the destination user station 200 an electronic mail (e-mail) which indicates that

  the information is made available to the user of extension 200.

  During the operation 14, the user accesses the internal application 110 by selecting his Internet address. During operation 15, the Internet application

  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 given sets. It is observed that the application routines downloaded during operations 1 and 15 can 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.

  Operations 16 and 17 correspond to an example of a signature which can be used in combination with 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. Primarily, 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 will be able to refer to the patent application PCT / FR98 / 02348 for better knowing examples of steps implemented during operations 16 and 17. During operation 17,1 '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 sccau 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.

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  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 the operation

18 and 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 have been transmitted to the destination user terminal 200 with integrity, that is to say that the data to

  transmit were not changed after operation 20.

  During operation 24, a trace of the data transmission to the recipient user is certified and stored in the storage memory 130.

  date is associated with the transmitted data and is thus time-stamped, archived and notarisoe.

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

Datas.

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

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  , 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 receiver 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 sets of data 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 server of

  120 security 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 which is the subject of the present invention portable, without slowing down this process in the case where the user successively sets 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

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  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 an e-mail address. ), telephone number or any other type of information making it possible to contact each recipient of the data to be transmitted. During operation 36, the integrity of the data sets to be transmitted is checked, by implementing the key

  disposable generated during operation 32 and condensed.

  It is observed that at the end of operation 36, a copy of the data sets 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 as being 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, i.e. it becomes

  unusable for certifying datasets.

  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 certificate

  disposable, 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. Primarily, the secret seal depends on the data to be transmitted, their number, their content, the date and time of generation of the secret seal, the private key of the data transmitter determined in correspondence with the identifier of the user kansmis 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 calculation of a condensed of data to be transmitted, for example in the form of a sequence of 20 symbols, of encryption of this condensed by the private key of the user of the user station 100 and extraction of a

  part of the result of this encryption.

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

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  of operations 37 and 38. During operation 38, the common user of the user station 100 and of the receiver 150 enters the secret sccau 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, i.e. infrastructure for

  public keys) upon signature during operations 37 and 38.

  During operation 39, the transmitted data sets are signed

  with the private key of the user who transmitted it (known as the "signatory" of the data).

  Finally, during operation 41, the data sets transmitted, certified and signed by private key are transmitted to the storage memory 130 with a

  1 S dates in such a way that they are time-stamped, archived and notarized.

  In an application of the present invention to hand 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 data set 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 addressee after having received a signature from him. An example of a succession of operations implemented for this hand delivery is given in

figure 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

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  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, the O or another network computer, connected to the Internet. The first and third networks can be confused or different. The first and third networks can

so 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. Preferably, the communication devices 401 and 404 have unique addresses on the second and the fourth network of

communication, 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, we consider

  that the receiving computer system 403 retains the means necessary to obtain - a private key and a public key of 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:

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  - the private key and the public key of each user likely to implement the method described in FIG. 4, - a correspondence table between user identifiers and addresses on the second communication medium, and - a means of query 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 computer systems and communication devices are not represented in

figure 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 recipient computer system 405, - a condensa 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

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  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 a

  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 disturbed 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 communication 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 supplies said part of the trace to the computer system 401 transmitter through a

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 system

computer receiver 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 figure 4, an equality between the trace emitted and the trace received. 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 sending user to start again the operations illustrated in figure 4.

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  If there is a match, during a matching operation 420, the receiving computer system 403 matches

  said data with a public key of the user émeKeur.

  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 system

computer receiver 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 corumunication 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 the

  through any user interface.

  During a transmission operation of said confidential information 426, said confidential information is transmitted from the system

  recipient computer 405 to receiver computer system 403.

  During a correspondence verification operation 427, the receiving computer system 403 verifies 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 medium of

  communication and invites it to repeat operations 422 and following.

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  When there is a match, 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.

  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 kansmitted calculated during the operation, and

  - a program for determining said condensa 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 condensa

  said data which was used to generate the trace transmitted during operation 428.

  When the two condensa are equal, the recipient user has the assurance that it is the sending user who transmitted the data to be transmitted and that this data has not

  have 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 figure 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 key

  private of the sending user, is implemented.

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Claims (13)

  1. Signature process, characterized in that it comprises: - a step of attributing a signature to a user, - a step of opening a communication session, on a computer network, between a computer system transmitter and a remote receiving computer system, - a step of authenticating the user of said sending computer system, - a step of transmitting, from the sending computer system to the remote receiving computer system, via the computer network, information representative of data to be signed, - a step of signing, by the remote receiving computer system, with the signature attributed to the user, information representative of the data to be signed, and - when a recipient of the document wishes to verify the authenticity of said data, a step of verifying the signature of the information representative of said data. 2. Method according to claim 1, characterized in that said signature assigned to the user is a private key of a pair of signatures conforming to the key infrastructure public PKI.   3. Method according to any of claims 1 or 2, characterized in that it   includes a step of memorizing, by the remote receiving computer system, of   said signature attributes to the user.   4. Method according to any one of claims 1 to 3, characterized in that   the information representative of the data to be signed is a condensate of said data.   5. Method according to any one of claims 1 to 4, characterized in that the step   transmission of information representative of said data is carried out in encrypted mode.   6. Method according to any one of claims 1 or 5, characterized in that at   at least one step of transmitting the information representative of said data includes a step of transmitting, by the receiving computer system remote to said   IT system issuing an application routine.   7. Method according to any one of claims 1 to 6, characterized in that it   includes, for each data signing step, a step of generating a certificate by the remote receiving computer system, said certifcat being implemented 2 2823930   by the issuing computer system, during the step of transmitting the information representative of the data and a step of revoking said certificate after the step of   transmission of information representative of the data.   8. Method according to any one of claims 1 to 7, characterized in that the step   user authentication comprises a step of transmitting, on a terminal of a telecommunication network, different from the transmitting computer system, of non-predictable information and a step of transmitting non-predictable information,   from the sending computer system to the remote receiving computer system.   9. Method according to any one of claims 1 to 8, characterized in that the step   signature assignment and the signature step are performed on two subsystems   remote computers connected by a computer network.   10. Method according to any one of claims 1 to 9, characterized in that the step   signature includes a step of associating a date and time with the data transmitted, and during the signature verification step, the date of signature is made available to third parties.   8. Certification process according to any one of claims 1 to 7, characterized in what it involves an operation   11. Method according to any one of claims 1 or 10, characterized in that it   includes a step of memorizing each step of signing effectuce by the   remote receiver computer system.   12. Certification method according to any one of claims 1 to 11, characterized   in that the signature step comprises an operation of substitution, for a certificate implemented during the step of transmitting information representative of said data, the signature assigned to the user to sign said information with said signature.   13. Certification process according to any one of claims 1 to 11, characterized   in that, during the signature verification step, the third party implements a public signature attributed to the user of the issuing computer system during