Digital photograph transmitting process for e.g. mobile telephone, involves verifying digital signature associated to received signed digital photograph by digital signature management device

The present invention relates to a method and a system for transmitting a digital photograph from a mobile terminal to communication equipment.

At present, it is possible to send digital photographs from a mobile telephone, in particular equipped with a digital camera, to communication equipment, for example a personal computer or a mobile terminal.

The drawback of this type of transmission lies in the fact that the communication channel between the two devices is not secure. Thus, the photographs can be falsified and the identification of the issuer remains uncertain.

Also, the technical problem to be solved by the object of the present invention is to provide a method and a system for transmitting a digital photograph, which can be carried out in a secure manner.

To this end, the method according to the invention comprises the following steps:

- a) calculation, by the mobile terminal, of an electronic signature relating to the digital photograph,

- b) transmission of the signed digital photograph to an electronic signature management device, via an information transmission means,

- c) verification, by the electronic signature management device, of the signature associated with the signed digital photograph received.

In a preferred embodiment of the method according to the invention, one or other of the following arrangements is used:

- prior to step a), entering a signature code on the mobile terminal,

- prior to step b), transmission of the signed digital photograph to the communication equipment,

- in step b), the signed digital photograph is accompanied by access data to the communication equipment,

- Following step c), transmission of the signed digital photograph to the communication equipment if the verification carried out in step c) proves to be correct.

The system according to the invention comprises for its part:

- a mobile terminal which comprises means for transmitting / receiving data, means for entering data and means for calculating an electronic signature,

an electronic signature management device comprising means for receiving the signed digital photograph and means for verifying the signature associated with the signed digital photograph received.

In a preferred embodiment of the system according to the invention, one or the other of the following arrangements is used:

- the signature management device further comprises means for transmitting the signed digital photograph to the communication equipment,

the mobile terminal comprises storage means in which at least a private key is previously recorded, as well as all the information necessary for calculating a signature using a signature calculation algorithm,

- the signature management device contains beforehand a public key associated with the private key, as well as all the information necessary for the implementation of a signature verification algorithm, in association with access data to the terminal mobile,

- the storage means comprise an authentication module installed in the mobile terminal,

the storage means comprise a memory installed in the mobile terminal.

Other characteristics and advantages of the invention will become apparent from the following description of an embodiment, given by way of non-limiting example, with reference to the appended drawings.

On the drawings:

- Figure 1A shows the general architecture of the transmission system of a digital photograph according to a first embodiment,

- Figure 1B shows the general architecture of the transmission system of a digital photograph according to a second embodiment

First embodiment

A first embodiment of the system according to the present invention will now be described with reference to FIG. 1A.

This system includes:

- a mobile terminal 1 belonging to a user A, transmitter of a digital photograph,

- communication equipment 2 belonging to a user B, recipient of the digital photograph,

- an electronic signature management platform 3,

- a trusted authority 4,

- a communication network RA which allows the exchange of data between the mobile terminal 1 and the communication equipment 2.

In the example shown:

- the mobile terminal 1 is a mobile telephone,

- communication equipment 2 is a server,

- the RA communication network includes:

• a digital cellular radiotelephony network, denoted RRCN in FIG. 1a, for example of the GSM, GPRS, UMTS type, or according to the 802.11b standard called WiFi, ...

• an RI data network, for example of the Internet type, coupled to the RRCN network by a gateway (not shown).

As an alternative, the mobile terminal 1 is a personal digital assistant or the like.

Also as an alternative, the data network RI is of the X25 type.

More specifically, the mobile telephone 1 comprises in particular:

- an authentication module 1a, such as for example a SIM card (Subscriber Identity Module),

a module 1b for transmitting / receiving multimedia type data, in particular MMS (contraction of the English-speaking term Multimedia Message Service), which is intended to communicate with the RRCN network,

- an image memory 1c,

- a 1d keyboard,

- a 1st screen,

- a bus 1f interconnecting the aforementioned modules.

More particularly in the embodiment shown, a software application, intended to produce and send an electronic signature, is recorded in the SIM card 1a.

Such an electronic signature is preferably based on a public key infrastructure (PKI for Public Key Infrastructure) known as such.

For this purpose, a private key S and a signing certificate C associated with a public key K are also previously recorded in the SIM card 1a.

As an alternative, it is not the C certificate which is stored in the SIM card 1a, but a pointer to an Internet address (URL, Uniform Resource Locator) where the C certificate is stored.

Also as an alternative, the aforementioned software application, as well as the private key S and the signing certificate C, are previously recorded in a dedicated memory (not shown) of the mobile telephone 1.

The public key K, as well as all the information necessary for the implementation of a signature verification software application, are recorded beforehand in the platform 3, in association with an identifier of the mobile telephone 1, for example the mobile phone number 1.

As an alternative, the public key K is recorded beforehand in a database (not shown) accessible by the platform 3, via an Internet type network.

In the example shown, server 2 includes:

- a communication interface 2a with the Internet network RI,

- an application server 2b connected to interface 2a,

- a database 2c intended to store the digital photograph received,

- an internal 2d bus connecting the aforementioned modules.

The mobile telephone 1 communicates with a multimedia type message server 9, in particular MMS, belonging to the RRCN mobile communication network, said MMS server 9 being intended, in a manner known as such, to manage the reception and sending of messages. MMS messages.

Finally, platform 3 includes:

- a communication interface 3a with the Internet network RI,

- an application server 3b intended to process the messages coming from the server 2,

- an internal bus 3c connecting the aforementioned modules.

A method of transmitting a digital photograph according to the first embodiment shown in Fig. 1A will now be described.

User A takes a digital photograph using a digital still camera (not shown).

Such a device is either integrated in a conventional manner into the mobile telephone 1, or connected to the latter by a proximity link which can be a radio link of the Bluetooth type, or according to the 802.11b standard called Wifi, or an infrared link. ..

In a manner known as such, the digital photograph is then transferred to the image memory 1c of the mobile telephone 1.

As an alternative, the digital still camera is not necessarily used in the method, a digital photograph may already have been transmitted to the mobile phone 1 by any means, then stored in the image memory 1c.

User A selects the “send a signed digital photograph” function from a menu displayed on the screen 1e of his mobile telephone 1. A “signature code entry” message is then displayed on screen 1e. User A enters a signature code on the keypad 1d of his mobile telephone 1. Firstly, the SIM card 1a verifies this signature code by comparing it with a signature code Z previously stored in the latter.

If the result of the verification is found to be correct, the SIM card 1a signs the digital photograph using the registered private key S.

A message “entering your correspondent's access data” is then displayed on screen 1e.

User A then enters on keypad 1d of his mobile phone 1 the address of server 2.

In the example shown, such an address consists of a short number.

This address could in other examples consist of an e-mail address or a telephone number.

In a manner known as such, the transmission / reception module 1b of the mobile telephone 1 then transmits to the server 2, via the MMS message server 9 of the RRCN communication network and the Internet network RI, a message m1 which contains:

- the multimedia file containing the digital photograph stored in the memory 1c of the mobile phone 1,

- the signature which has just been produced.

The interface 2a of the server 2 receives the message m1 and transmits it to the application server 2b, via the bus 2d. The server 2b then transmits for storage to the database 2c, via the bus 2d, the digital photograph, the associated signature and information identifying the photograph.

In the event that user B wishes to ensure that user A has actually signed the message m1 and that the photograph has not been modified between transmission and reception, the communication interface 2a of the server 2b sends to the platform 3, via the Internet network RI, a message m2 containing the multimedia file and the signature mentioned above, so that the platform 3 verifies this information.

The communication interface 3a receives the message m2 and transmits it, via the bus 3c, to the application server 3b which verifies the signature by means of the software application for verifying the signature and the public key K previously recorded.

If the certificate C has been added to the signature, the platform 3 verifies this certificate with the trusted authority 4. For this purpose, the communication interface 3a is linked to the trusted authority 4 by a secure link LS, for example of the HTTPS type. The platform 3 then sends back to the server 2 a message m3 which contains the result of the verification. In particular, the message m3 contains data which makes it possible to retrieve the message, such as for example a transaction number and a code defining the result of the verification of the signature.

Second embodiment

A second embodiment of the system according to the present invention will now be described with reference to FIG. 1B.

This system includes:

- a mobile terminal T belonging to a user A, transmitter of a digital photograph,

- communication equipment 2 'belonging to a user B, recipient of the digital photograph,

- a 3 'electronic signature management platform,

- a trusted authority 4 ',

- a communication network RA which allows the exchange of data between, on the one hand, the mobile terminal 1 'and the platform 3', and, on the other hand, the platform 3 'and the equipment communication 2 '.

In the example shown:

- the mobile terminal is a mobile phone,

- the communication equipment 2 ′ is a conventional mobile telephone, for example of the GSM, GSM / GPRS or UMTS type,

- the communication network RA 'comprises:

• a digital cellular radiotelephony network, denoted RRCN 'in FIG. 1b, for example of the GSM, GPRS, UMTS type, or according to the 802.11b standard called WiFi, ...

• a data network RI ', for example of the Internet type, coupled to the network RRCN' by a gateway (not shown).

More specifically, the mobile phone includes it in particular:

- an authentication module Ta, such as for example a SIM card (Subscriber Identity Module),

a module 1'b for transmitting / receiving multimedia type data, in particular MMS (contraction of the English-speaking term Multimedia Message Service), which is intended to communicate with the RRCN 'network,

- a 1'c image memory,

- a Td keyboard,

- a 1'e screen,

- A bus 1'f interconnecting the aforementioned modules.

As in the first embodiment, are previously recorded in the SIM card Ta:

- a software application, intended to produce and issue an electronic signature,

a private key S 'and a certificate C' associated with a public key K '.

The public key K ′, as well as all the information necessary for the implementation of a signature verification software application, are also recorded beforehand in the platform 3 ′, in association with an identifier of the mobile telephone 1 ′. , for example the telephone number of the mobile phone Γ.

In the example shown, the mobile telephone 2 'comprises:

a first MMS communication interface 2 ′ a with an MMS message server 9 ′ belonging to the mobile communication network RRCN ′, said MMS server 9 ′ being intended, in a manner known as such, to manage the reception and the sending MMS messages.

- a 2'b image memory,

- a 2'c screen,

- an internal bus 2'd connecting the aforementioned modules.

Finally, the 3 'platform includes:

- a first communication interface 3'a with the Internet network RI ',

- an application server 3'b intended to process Internet messages, - an internal bus 3'c connecting the aforementioned modules.

A method of transmitting a digital photograph according to the second embodiment shown in Fig. 1B will now be described.

User A takes a digital photograph in the same way as in the first embodiment.

In a manner known as such, the digital photograph is then transferred to the image memory 1'c of the mobile telephone Γ.

User A selects, from a menu displayed on the screen 1'e of his mobile telephone Γ, the function “sending a signed digital photograph to signature management platform”. A message “Entering the signature code” is then displayed on the screen 1'e. User A enters a signature code on the keypad 1'd of his mobile phone Γ. Initially, the ίο SIM card Ta verifies this signature code by comparing it with a signature code Z 'previously recorded in the latter.

If the result of the verification is correct, the SIM card Ta signs the digital photograph using the private key S '.

A first message for entering platform access data is then displayed on the screen e.

User A then enters on the keypad the d of his mobile phone at the address of the platform 3 '.

A second message entry of the access data of the final recipient of the signed digital photograph is then displayed on the screen îe.

The user A then enters on the keypad îd of his mobile telephone Γ an identifier of the mobile telephone 2 'intended to be addressed to the platform 3', for example the telephone number of the mobile telephone 2 '.

In the example shown, the address of the platform 3 ′ consists of a short number.

This address could in other examples consist of an e-mail address or a telephone number.

In a manner known as such, the transmission / reception module 1'b of the mobile telephone Γ then transmits in the direction of the platform 3 ', via the MMS server 9' of the network RRCN 'and the Internet network RI' , a message m'1 which contains:

- the multimedia file containing the digital photograph stored in the memory îb of the mobile telephone 1,

- the signature which has just been produced,

- the telephone number of mobile phone 2 '.

The Internet interface 3'a of the platform 3 'receives the message m'1 and transmits it to the application server 3'b, via the bus 3'c. The server 3'b extracts from the message m'1 the signature which has just been produced and verifies the latter by means of the software application for verifying the signature and the public key K 'previously recorded.

If the certificate C has been added to the signature, the platform 3 ′ verifies this certificate with the trusted authority 4 ′. For this purpose, the communication interface 3'a is connected to the trusted authority 4 'by a secure link LS'.

If the result of the check is found to be correct, the Internet interface 3'a sends to the mobile phone 2 ', via the network RI', then RRCN ', an MMS message, m'2, which contains at least:

- the multimedia file containing the digital photograph,

- electronic signature,

- and a code indicating that the signature is valid.

The transmission / reception module 2'b of the mobile telephone 2 'receives the message m'2 and the user B is notified of the receipt of this message by a receipt notice which is for example in the form of a icon displayed on the screen 2'c of his mobile phone 2 '. The signed digital photograph is then transferred to the image memory 2'b, via the bus 2'd.

If the result of the check is incorrect, the Internet interface 3'a sends to the mobile telephone T of user A, via the network RI ', then RRCN', an MMS message, m'3, which contains a code indicating that the signature is not valid.

In the latter case, the Internet interface 3'a does not send any message to the telephone 2 'of user B.

It goes without saying that the two embodiments which have been described above have been given purely as an indication and in no way limiting, and that many modifications can be easily made by those skilled in the art without departing from the scope of invention.

Thus the server 2 of FIG. 1A or the mobile telephone 2 'of FIG. 1B could be replaced, for example, by a personal computer or a personal digital assistant.

This is also how the server 2 could be replaced by a mobile phone. To this end, the mobile phone 1 and the mobile phone 2 would communicate with each other through the RRCN cellular network, while the mobile phone 2 and the platform 3 would communicate with each other through the RRCN cellular network and the RI Internet network.

Also, the message m1 or m'1 sent by user A could be an electronic message instead of a multimedia message. The message received by user B would then be stored in an electronic messaging server 5 to which user B would have access, either by means of his terminal 2 or 2 ', or by means of other communication equipment at his disposal. .