FR3081067A1 - SECURE METHOD AND SYSTEM FOR DELAYED DATA SHARING BETWEEN AT LEAST ONE TRANSMITTER USER AND AT LEAST ONE RECIPIENT USER. - Google Patents

Abstract

File sharing method (2) between at least one user (Ai) sender and at least one user (Bk) recipient, which comprises several phases: - Writing: ○ Create, on request of at least one user (Ai) issuer a container (6) of data associated with the recipient user (Bk); ○ Allow the sending user (Ai) write access to the container (6); - Archiving: ○ At the end of the write phase, encrypt the container (6); ○ During an archiving delay (T2), store the encrypted container (6Bk); - Sharing: decrypt the container (6Bk) to allow access to the recipient user (Bk).

Description

Secure method and system for delayed data sharing between at least one sending user and at least one receiving user

The invention relates to the field of computing, and more specifically to the sharing of computer data files between at least one sending user and at least one receiving user.

The term “user” is used here to designate a communicating device (in English “user device”), typically a smartphone, a tablet, or more generally a computer, for example. a portable or fixed computer or a workstation capable of connecting, via a local computer network (LAN), metropolitan (MAN) or extended (WAN, typically the Internet), to a remote server, the term "server ”Designating here a physical unit or, in a virtualization framework, a computing and / or memory space allocated within a physical unit and on which an operating system or an operating system emulation is running.

However, we understand that a real user (that is to say a natural or legal person) who carries out operations using this device is associated with such an electronic client device.

The use of computer networks is quite widespread today, especially for data sharing.

There are various types of systems for sharing data.

Mailbox-type e-mails, which work asynchronously, allow user A (sender) to address user B (recipient) a message containing information that can be included in the body of the message itself , or as attached files.

In an electronic messaging system, the message delivery time depends essentially on the bandwidth (availability) of the network connecting the sending and receiving users, and on the memory size of the message, including its any attachments.

Quite often, routing takes a few seconds. The recipient can then open and read the message from the sender whenever they want.

At the time of writing, e-mail is limited in size to the messages sent, usually around ten megabytes (MB).

To exchange data of large volume (that is to say of size greater than 10 MB), it has become customary to use specialized platforms, e.g. DropBox (registered trademark).

In principle, these platforms aim to allow permanent access to a private memory space on which files are stored, for any user identified as having the right to it.

Hacking files involves either unauthorized access to this memory space, or the theft of the identity of a user with access rights.

These platforms are easy to use but nevertheless meet limits with regard to data security. In particular, identity theft is very effective in accessing data immediately, and - in general - both read and write.

There therefore remains a need to share computer data files between users, with a higher degree of security, while preserving a certain simplicity of use.

To this end, it is proposed, firstly, a process for sharing computer data files between at least one sending user and at least one receiving user, this process comprising three successive phases:

A writing phase, which includes the operations of:

o Create, at the request of at least one sending user, at least one data container to share, associated with the user (or each user) recipient;

o As long as no end of writing instruction has been taken into account, allow each sending user write access to the container;

An archiving phase, which includes the operations of:

o When taking the end of writing instruction into account, encrypt the or each container to form an encrypted container associated with each recipient;

o Associate the (or each) encrypted container with a predetermined archiving period;

o As long as the archiving period has not expired, store the encrypted container by preventing access to it at least to the recipient user (or to each recipient user);

A sharing phase, which includes the operation of decrypting the container at the end of the archiving period to allow the recipient user (or each user) to access it.

Various additional characteristics can be provided, alone or in combination. So, for example:

It is advantageously provided, during the writing phase, an operation consisting in associating with the container a predetermined writing period at the end of which an end of writing instruction is issued.

The write time can be set by the sending user, or automatically.

The archiving period can be defined by the sending user, or automatically.

The archiving period can be defined separately for each recipient user.

Other objects and advantages of the invention will emerge in the light of the description of an embodiment, given below with reference to the appended drawings in which:

FIG.1 is a synthetic diagram of a computer system illustrating the writing phase of a method according to the invention;

FIG.2 is a diagram similar to FIG.1, illustrating the archiving phase;

FIG.3 is a diagram similar to FIG.1, illustrating the sharing phase;

FIG.4 is a diagram illustrating different stages of the process of the invention.

In FIG. 1 to FIG. 3 is shown a computer system 1, intended to allow the sharing of files 2 of computer data between at least one user Ai transmitter (i an integer such as 1 <i <N; N an integer such than N> 1) and at least one recipient Bk user (k an integer such as 1 <k <P; P an integer such as P> 1).

The term “user” here designates, in concrete terms, an electronic device, such as a smartphone, a computer, a tablet, and provided with a communication interface (wired or wireless) through which this device is capable to connect to a remote server, via a local (LAN), metropolitan (MAN) or wide area network (WIDE, such as the Internet). It is understood, however, that, by extension, the term “user” indirectly designates one (or more) real user (s) (for example a natural or legal person) associated with this device.

The computer system 1 comprises, first of all, a communication server 4, programmed to be able to establish communication sessions (preferably secure) with users (in particular with users Ai and Bk).

The computer system 1 comprises, secondly, a file server 5, on which directories or “containers” 6 of data files to be shared can be created or deposited. In these containers can be created, deposited, copied, pasted, deleted, modified, 2 data files of any type, eg. files from office applications (eg word processing, spreadsheet), sound, image, or video files.

The computer system 1 comprises, thirdly, a profile database 7 which contains profiles PAi, PBk of users in memory. In this case, the database contains at least one PAi profile associated with each sending Ai user, and a PBk profile associated with each receiving Bk user.

Each PAi, PBk user profile includes at least one IDAi, IDBk identifier linked to the respective user Ai, Bk (eg a name, an email address, a telephone number) and at least one respective public cryptographic key ZAi, ZBk .

To this public cryptographic key ZAi, ZBk corresponds a respective private cryptographic key AiZ, BkZ.

The private cryptographic AiZ, BkZ key associated with each user Ai or Bk is stored locally in a memory space thereof.

The computer system 1 comprises, fourthly, a control unit 8, connected to the communication server 4, to the file server 5 and to the database 7. The control unit 8 comprises at least one processor and a programmable memory. The control unit 8 is programmed to control the communication server 4, the file server 5 and to administer the database 7.

The sharing of data between at least one sending user Ai and at least one receiving user Bk comprises three phases.

A first phase, called writing, includes the operations of:

o Create, at the request of at least one sending Ai user, at least one container 6 of data to be shared;

o As long as no end of write instruction has been taken into account, allow each sending user Ai write access to container 6.

The container 6 can be created locally by a sending Ai user, for example when this sending Ai user is unique (N = 1; i = 1), or, as in the example illustrated, on the file server 5, in particular when several transmitting Ai users share this container 6.

During the writing phase, each sending user Ai is authorized to modify the container 6 by adding or subtracting from it data files 2. These data files 2 can come from (or from each) terminal Ai itself, or be downloaded from remote servers via the network 3.

According to a preferred embodiment, a writing delay T1 (shown diagrammatically in the drawings by a first countdown) is advantageously defined by a user A1 master transmitter, or automatically by the control unit 8. The T1 writing delay is advantageously implemented within the IT system 1, e.g. by means of an internal clock controlled by (or integrated into) the control unit 8.

It is at the end of this T1 writing period that the end of writing instruction is issued.

A second phase, called archiving, includes the operations of:

o When taking the write end instruction into account (that is to say, in the example presented above, at the end of the T1 write delay), encrypt the or each container (6) to form an encrypted container (6Bk) associated with each recipient (Bk);

o Associate (or each) encrypted container (6Bk) with a predetermined archiving time (T2);

o As long as the archiving period (T2) has not expired, store the encrypted container (6Bk) by preventing access to it at least to the recipient user (Bk).

According to a preferred embodiment, the encryption is carried out by means of the public key ZBk of the recipient (or of each) user Bk. When several users Bk are designated during the creation of the container 6, the container 6 is advantageously copied in as many copies as there are recipients, each copy being in this case preferably encrypted by means of the public key ZBk of the corresponding user Bk.

The T2 archiving period (shown schematically in the drawings by a second countdown) can be defined by the user A1 master transmitter, or automatically. The T2 archiving period is advantageously implemented within the IT system 1, e.g. by means of an internal clock controlled by (or integrated into) the control unit 8.

The T2 archiving period is advantageously greater than one hour. It is preferably greater than one day. It can reach a month or even one or more years.

The T2 archiving period can be defined separately for each recipient Bk user.

According to a preferred embodiment, the control unit 8 is devoid of instructions for communicating to each recipient user Bk, during the archiving phase, the very existence of a container 6 or a container 6Bk encrypted to its attention, so that the actual users associated with the recipient Bk users are kept in the dark about this existence.

A third phase, known as sharing, includes the operation consisting, at the end of the T2 archiving period, of decrypting the container 6 (or each copy of it) to allow access to the user ( or to each recipient) (Bk).

In practice, the sharing phase consists in allowing each recipient Bk user to download the encrypted 6Bk container in order to decrypt it using their private BkZ key.

Concretely, the control unit 8 is for example. programmed to send to the recipient user Bk (in particular via the communication server 4) a notification of availability of the encrypted container 6Bk. This notification advantageously contains an identifier IDAi associated with at least one sending user Ai, or an identifier IDAi associated with each sending user Ai. The download is then preferably ordered by the recipient user Bk, rather than carried out automatically on command from the control unit 8. Knowledge at least of the profile IDAi of the user (or of each user) Ai sending by the user Bk recipient can constitute for the latter an index of confidence of the origin and / or the harmlessness of the data shared by the Users have transmitters.

Concretely, each encrypted container 6Bk is sent, on command from the control unit 8, to the corresponding recipient user Bk via the network 3. The decryption is carried out locally by the recipient user Bk, using his key Private BkZ stored locally. The recipient user Bk can then read (and if necessary write) the container 6, that is to say the data files 2 which it contains, as deposited at the initiative of the user Has transmitter.

After decryption, the data files 2 can be stored locally by each recipient Bk user.

At the end of the decryption, each recipient Bk user can send (automatically or on external command) to system 1 a decryption notification. This notification is received by the communication server 4.

In this case, it is advantageously provided for the destruction of the (or each) corresponding encrypted container 6Bk on the file server 5 after reception, by the system 1, of the decryption notification.

In this way, memory space is freed up within the file server 5, which facilitates the subsequent creation of new containers 6.

The process which has just been presented offers a certain advantage in terms of safety compared with the known processes (respectively the systems). Indeed, during the archiving phase, the data in files 2 cannot be read - nor a fortiori modified - by the user (or each user) Ai sending or by any of the users Bk recipients. Any impersonation of any of them is ineffective since it is necessary to have the private key of the recipient user Bk to decrypt the container 6Bk.

We even see that the control exerted by the user (or by each user) Ai on the container 6 (that is to say on the data files 2 to be shared) ceases at the expiration of the T1 writing delay , even though its content is not yet accessible to any recipient Bk user. The delay (predetermined) with which the recipient Bk users 10 accesses the files 2 of data shared by the sending Ai users makes any dialogue between them impossible in real time, to the benefit of the parsimony with which the users exchange data with each other. This notably results in an optimization of the bandwidth necessary, in networks, for exchanges between users.

Claims (6)

1. Method for sharing files (2) of computer data between at least one sending user (Ai) (i an integer such as 1 <i <N; N an integer such as N> 1) and at least one user (Bk ) addressee (k an integer such as 1 <k <P; P an integer such as P> 1;), this process being characterized in that it comprises three successive phases: A writing phase, which includes the operations of: o Create, at the request of at least one sending user (Ai), at least one container (6) of data to be shared, associated with the recipient user (or each user) (Bk); o As long as no write end instruction has been taken into account, allow each sending user (Ai) write access to the container (6); An archiving phase, which includes the operations of: o When taking the end of writing instruction into account, encrypt the or each container (6) to form an encrypted container (6Bk) associated with each recipient (Bk); o Associate (or each) encrypted container (6Bk) with a predetermined archiving time (T2); o As long as the archiving period (T2) has not expired, store the encrypted container (6Bk) by prohibiting access to it at least to the recipient user (Bk); A sharing phase, which includes the operation consisting, at the end of the archiving period (T2), of decrypting the container (6) to allow access to the user (or to each user) (Bk ) recipient. 2. Method according to claim 1, which comprises, during the writing phase, an operation consisting in associating with the container (6) a predetermined writing delay (T1) at the end of which an instruction to end writing is issued. 3. Method according to claim 2, in which the writing delay (T1) is defined by a sending user (Ai). 4. The method of claim 2, wherein the writing delay (T1) is automatically defined. 5. Method according to one of claims 1 to 4, wherein the archiving time (T2) is defined by a user (Ai) transmitter. 6. Method according to one of claims 1 to 4, wherein the archiving time (T2) is automatically defined.