EP2452286A1

EP2452286A1 - Making the location of a remote code secure through the recipient's imprint

Info

Publication number: EP2452286A1
Application number: EP10725742A
Authority: EP
Inventors: Jacques Fournier; Laurent Gauteron; Franck Imoucha; Véronique Charpeignet
Original assignee: Gemalto SA
Current assignee: Thales DIS France SA
Priority date: 2009-07-06
Filing date: 2010-06-18
Publication date: 2012-05-16
Also published as: US20120110265A1; JP2012532392A; WO2011003721A1; US9053331B2; JP5546631B2; EP2273407A1

Abstract

Method of securing exchanges between two electronic devices, by using an imprint of at least one of the two devices. This imprint is obtained on the basis of all or some of the electronic components of which this device is composed. This imprint will serve, either to protect the confidentiality of the data exchanged, or to attest to the identity of the device issuing the data.

Description

- Securing the location of a remote code through the fingerprint

of the recipient -

The invention relates to securing the location of a remote code through the recipient's fingerprint.

In particular, the invention relates to securing exchanges between two devices during the execution of a distributed code.

Mobile electronic devices are changing. Indeed, their storage capacity is changing, their computing power per unit size increases as their footprint decreases.

A new generation of such devices has made it possible to develop a new distributed model. These devices, commonly called Intelligent Keys, have the particularity of having a memory, an electronic intelligence, and access to a secure electronic module. In the memory of these Intelligent Keys is stored an executable computer code (one or more software), which is intended to be loaded (through the communication interface of the Intelligent Key, often USB) on another host electronic device said device execution.

This particular code is commonly called CDROM because in most cases, this code is stored as an 'ISO' image on a 'Read Only' partition that emulates a CD-ROM that will be seen as such (ie to the a "compact disc") by the host electronic device (the computer).

In general, when the Smart Key is inserted into a computer, the computer detects it, recognizes it, and activates it. The activation phase involves, among other things, mounting on the operating system the different

'discs' presented by the Intelligent Key, including the one containing the CD-ROM. Once activated, the Key

Smart then sends the contents of the CDROM to the computer that is running the content.

This technology can transport executable code, potentially large, on a non-fixed media, and this through a USB communication interface widely deployed on computers. Indeed, the compact disc, and its subsequent generations, can transport such a computer code, but in a static manner.

Intelligent Keys offer the possibility of developing this computer code, but also a whole set of functionalities related to embedded intelligence and the secure electronic module. These features can for example be related to security.

In addition, these devices make it possible to execute computer applications on a device (called an execution device) without relying on the software resources of this execution device. Indeed, the computer code provided by the Intelligent Key only uses the electronic resources of the execution device.

This makes it possible to use software on a device without having to trust this device, and without leaving a trace because the computer code executed is not not stored on runtime device permanently or persistently.

A major risk of this system lies in the fact that the execution device may include a malicious program type, for example, computer virus or Trojan.

Strictly speaking, a computer virus is a computer program written for the purpose of spreading to other computers by inserting into legitimate programs called "hosts". It can also have the effect, wanted or not, of harming by disrupting more or less seriously the operation of the infected computer.

Trojans are programs that perform damaging actions while presenting themselves to the user as useful applications or files.

Whatever the malicious program ("malware" in English), it is not uncommon to find those whose primary function is to serve as a bridgehead. This expression refers to a program that captures all or part of the events that occurred on the infected computer, and transmits them (usually via the internet) to a so-called attacking computer, and vice versa. This mechanism allows among other things to spy on the infected computer, but also to divert some of these applications.

Indeed, in the context of the use of a program from a smart key on an infected computer, and where the attacking computer has a copy of this program (because it is legally in possession of a key similarly intelligent, or that he obtained the contents of the mass memory by some means), the malware will allow the computer attacker, for example, to use the services of the smart key without the knowledge of its legitimate owner.

Indeed, we defined such a malware as being able to spy on the events that occurred on the infected computer, and to transmit them to the attacking computer, and vice versa.

Thus, it is possible for it to spy on the exchanges between the application that is running on the infected computer and the smart key that is connected to it. Thus, it is possible for it to provide the application running on the attacking computer with the same information as received by the application that is running on the infected computer. This technique is called application synchronization. In return it is also possible for the attacking computer to perform actions on its application, and when it needs the services of the smart key, to send the requests to the malware on the infected computer, which transmits to the smart key by making it believe that it comes from the application on the infected computer.

By this hijacking mechanism, an attacker will use a service or feature, provided by the intelligent key of his victim, without his knowledge.

The present invention proposes to prevent such attacks.

To do this, the invention notably describes a security method, comprising at least a first electronic device called "smart key", able to communicate with at least a second electronic device called "computer", the electronic device "smart key" comprising at least one controller, a mass memory in which is recorded a first executable computer code, also comprising access to a second executable computer code called the Secure Agent, the first executable computer code being intended to be executed by the "computer" device. This method comprises at least the steps of:

• recognition, in which the controller transmits the first Secure Agent executable code to the "computer" device, and orders its execution on the "computer" device,

• collection, in which the Secure Agent code collects information related to all or part of the electronic components that make up the "computer" device,

• creation (or generation, both terms are correct) of a fingerprint of the device "computer" from the collected information,

• securing all or part of the data exchanged between the "computer" and "smart key" devices, using the fingerprint.

In one embodiment, the information related to all or part of the electronic components that make up the "computer" device can be non-modifiable information.

This information can be, for example, serial numbers, or technical characteristics.

According to the embodiments, the fingerprint can be generated by said Secure Agent code, in another embodiment the collected information can be transmitted to the device "Smart Key" which generates the fingerprint, or the information collected can transmitted to a secure electronic device SE that generates the print.

The creation of the imprint may further include the use of non-fixed data, which may be a random number.

According to the embodiments, the method according to the invention can be implemented before executing the first executable code, or during the execution of the first executable code, for example triggered by it.

Other characteristics and advantages of the invention will clearly be apparent from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended drawings in which:

- Figure 1 shows the malicious operation of a malware according to the prior art.

- Figure 2 shows the implementation of the invention.

In Figure i, we can identify a smart key 2, which is connected to an electronic device 1. This device is represented by a computer. In normal operation of the system, the computer i and the key 2 communicate through a communication channel illustrated by the double arrow 4. This channel can be implemented by any computer communication protocol.

These protocols can be filai re such as T-carrier (Tl, T3, etc.), R3232, Ethernet, IDE, ... or wireless such as infrared, wifi, Bluetooth, RFID, ...

In a preferred mode of implementation of the invention, the key and the computer communicate through the TJSB protocol ("Un i ver sa 1 Se ria 1 Bus" in English). The use of this protocol allows key 2 to be easily connected to a personal computer such as the computer 1 of Figure 1, and recognized by him (through low-level software commonly called "drivers" that are present in the majority of operating systems).

The most advanced keys contain a security module 3 such as a smart card.

In order to easily manage the exchanges between the key 2, the computer 1 and possibly the secure module 3, it is common to insert a controller 6 in the smart keys. This controller, illustrated by the box 6 of FIG. 1, implies the presence, in the smart key 2, of at least one calculation component (microprocessor), a working memory (volatile memory), and a nonvolatile memory (eg RAM or ROM).

In addition, the key includes a nonvolatile memory 7, called mass memory, which contains an executable computer code 5 which we will call "application" in the remainder of this document.

When connecting the key 2 to the computer 1, the key receives the energy necessary to start it. Therefore, the controller 6 enters into communication with the computer 1.

During this phase, the controller initiates a communication session, this passes, among other things, by identifying the key by its type of electronic device (mass storage unit, multimedia device, etc.).

Also commits a communication during which the key informs the computer 1 that it contains an application 5, and that this application must be executed on the electronic resources of the computer 1. This communication can be done advantageously by identifying the application as a CDROM from the computer. In fact, when a CDROM is inserted into a computer, it identifies itself as such, and the standard response of the computer (or more precisely of the computer's operating system) is 'run the content, if it allows it (' autorun or autorun in English).

Once the application has been declared to the computer 1, the controller 6 of the key 2 sends the application 5 to the computer 1 which executes it 8.

This computer system allows, among other things, the execution of an application 5 on a computer 1 not having it. In addition the use of the security module 3 allows to restrict the use of the application 5 with the most advanced cryptographic tools. For example, it is possible to associate, with any invasive command for the application, an authent ic ion delegated to the security module (for example through the use of a personal code ("PIN code" in English). ).

In Figure 1, this application 8 esi represented by a telephone because we will illustrate the operation of the invention by taking the example of a sofLphone.

A softphone is a type of software used to make Internet telephony from a computer rather than a phone. In order to ensure an optimal level of security, some softphones work with the help of an external dongle, usually USB.

In the example illustrated by Figure 1, the code of the softphone 5 is contained in a non-volatile memory 7 of the key? .. _s and delivered to the computer 1 through a CD-ROM, The security module 3, In addition, it contains all the elements necessary for the authentication of the user on the telephony network. These Information is confidential: they are critical in the sense that their use entails not only billing for the user, but also his responsibility. Indeed fraudulent actions carried out through a private communication entail the responsibility of its owner.

In Figure 1, the pictogram 911 is shown in the computer i. This virus is in contact with its counterpart 10 on computer 11 of a hacker. The virus can communicate by any means, including infrared, Bluetooth, ..., the most common means being the sending of any internet connection 13.

To carry out its attack, the hacker has on his computer 11 a version 12 of the softphone application. it may be in possession of this version of the application in that it is also in possession of an intelligent key of the same type as the key 2, but whose rights have for example expired, or by 1 ' geti 11 icitede application, through illegal download for example.

In order to be able to function, to call in our example, the application 12, must have access to a key containing valid e 1 emen tio n fo rs, which the hacker does not possess.

The virus 10 will therefore come into contact with the virus 9 in order to exploit the elements contained in the secure module 3 of the de 2.

Indeed, the virus 10 can pass for a key from the softphone 12. Tl will receive the communications for a hypothetical key. This information will be transmitted to virus 9, which goes to in turn, send them to key 2 instead of softphone 8. The information returned by key 2 can go the same way in the opposite direction to be communicated to the softphone 12.

Figure 2 embodies the present invention in this scheme.

Indeed, prior to launching the softphone application 20, the method according to the invention calculates a fingerprint of the computer 21. This fingerprint is based on the computer electronics.

Indeed, an electronic device, such as a computer, is composed of a set of electronic components 22, 23, 24. These components are by definition unique. Indeed, two processors of the same model and the same series are different, for example by their serial numbers, two memories differ by their serial numbers or the arrangement of their addressable space. The invention consists in collecting this type of information, on certain components, in order to obtain a unique imprint of our device 21.

The use of serial numbers is a particularly efficient implementation, but the performance calculation also offers very good results.

The performance calculation is based on the fact that the same (relatively complex) operation entrusted to two components is performed in slightly different times. These times are also signatures of these components.

The invention therefore proposes an executable computer code 25, called a secondary agent, which is responsible for the collection of This Secure Agent is provided by the clp> 26, and executed on the computer 21, which it will analyze the components 22, 23, 24. This secure agent can be stored, either in a non-volatile memory 27 Oe the key 26, either in the security module 28. This secure agent can also be in charge of calculating the footprint 29, from the data collected. According to the embodiments, the secure agent can be transmitted and executed as soon as the intelligent die is initialized, or later, but in any case, before the use of the applications requiring the level of security provided by the invention. .

According to the implementation mode, all the components 22, 23, 24, having characteristic values can be set. As a preferred method of implementation, only certain components are used to define the footprint 29. The choice of these particular components can be made by their nature, or at a minimum, or by a combination of technical and technical factors.

For example, a solution consists in that, during the step of defining the imprint 29, the secure agent 25 collects a list of all or part of the components 22, 23, 24, capable of fu ing a characteristic v er. This list is transmitted to the key 26 which will select a subset of this list, and thus define the components whose values will create the footprint 29.

A particularly effective mode is a regular change of this subset, to guard against spying on communication, and a "reieu". "Replay" attacks are "Man in the middle" attacks that intercept and replay data packets, that is, retransmit them as they are. (without any decryption) to the recipient server.

In accordance with the invention, the calculation of the imprint 29 can be done in the computer 21, by a part of the application 20, in the key 26, or in the module secure 28.

The use of the secure module to generate the fingerprint makes it possible to exploit, during this generation, a turn or p a r t i e s of th e c y e rs p r e p a t i g e s i s e r e s i n e 1 secure module 23.

The generation of the imprint from the values of the selected components is done by the application of at least one mathematical function.

This function must be reproducible, that is, at a set of input parameters, the function matches one and only one result.

It may also be interesting to choose a non-invertible function, that is to say that from the result, it is not possible to return the input parameters,

Particularly effective examples of such functions are for example the "exclusive" function, or the hash functions.

A hash function is a function, which, to an element, is capable of associating a fingerprint (also called a hc) and a key to it.

- It must be impossible, starting from the hash, to find the information which served to σenerate it. It is informally impossible to find two data, whatever they are, which, applied to the same hash, give the same hash.

- From a data and its hash and a hash function, it is impossible to find another data that has the same hash.

The algorithms SHA-I (Secure Hash Algorichm 1: 160 bits), and SHA-2 (SHA-256, SHA-384 or SHA-512 bits of choice), s onτ: hash functions used frequently.

In a preferred embodiment of the invention, the generation of the fingerprint further comprises the use of another value. This value is a non-fixed value, which can be for example a random number.

Once the impression 29 obtained, it must be partacree by the application softphone 20 and the key 26, in order to secure all or part of the exchanged. It is generally the secure module 28 that retains and uses the imprint 29 for the 26,

A particularly interesting example of implementation of the invention, and to prevent the interception of the communication of this fingerprint 29, the Secure Agent 25 is loaded and executed on the computer 21, This secure agent collects the information on all or part of the components 22, z3 _f 24, of the computer 21, and transmits to the key 26.

The key 26, with the help of the secure module 28, selects a subset of this information, and generates a fingerprint 29 as explained above. This fingerprint is integrated in the program 2 Obi s, before it is loaded and executes on the computer 21. Thus, the progr amme 20 is in conn ection with the 2 9 th term, without the need for e 1

Computer 21 and Key 26 Securing exchanges can take many forms. Indeed, it can be one-way or two-way,

One way, it will be effective only for the information for example from the softphone application 20 to the key 26, or vice versa.

In this case, the softphone will use the imprint 29 on its messages, and the key 26 will check that the correct imprint has been used.

Then, security can, protect the exchanges in terms of confidentiality, or not.

If the choice has been made to protect itself in confidentiality, then secure exchanges will take the form of an encryption with a key composed in whole or in part, the print, and a secret key algorithm. If the choice has been made not to secure the exchanges in terms of confidentiality, then the security will take the form of marking the data exchanged to ensure their provenance. Applying the imprint at the end or at the beginning of the data can be a solution in this mode of impiementation. It can also be associated with the data to secure a hash thereof taking into account the footprint 29.

In the case where a piece of data, received by one of the devices of the system, does not have the expected security, this data will, in a preferred mode of impiementation of the invention, be ignored. At the same time, this data can be processed, but information can be saved for later analysis.

Thus, the virus 31, installed on the computer 21 can not relay information from the application 32 to the key 26 because it does not have the hollow 29 needed to ^"ia securing these data.

Claims

1. security method, comprising at least a first electronic device (2), able to communicate with at least one second electronic device (1), said electronic device (2) comprising at least one controller, a mass memory (7) in which is recorded a first executable computer code, access to a second executable computer code called

Secure Agent (25), said executable computer code (5) being intended to be executed by said device (1), characterized in that the method comprises at least the steps of:

Recognition, in which said controller transmits said first Secure Agent executable code (25) to the device (1), and orders its execution on said device (1),

• collection, wherein said Secure Agent code (25) collects information related to all or part of the electronic components (22, 23, 24) that make up said device (1),

Creating a fingerprint of said device (1) from said collected information,

• Securing all or part of the data exchanged between said devices (1) and (2) using said fingerprint.

2. Method according to claim 1, characterized in that said information related to all or part of the electronic components (22, 23, 24) that make up said device (1) are non-modifiable information.

3. Method according to claim 2, characterized in that said information is serial numbers.

4. Method according to claim 2, characterized in that said collected information is technical characteristics.

5. Method according to any one of claims 1 to 4, characterized in that said fingerprint (29) is generated by said Secure Agent code.

6. Method according to any one of claims 1 to 4, characterized in that said information is transmitted to the device (2) which generates said fingerprint (29).

7. Method according to any one of claims 1 to 4, characterized in that said information is transmitted to a secure electronic device SE which creates said fingerprint (29).

8. Method according to any one of claims 5 to 7, characterized in that said creation of the imprint further comprises the use of non-fixed data.

9. The method of claim 8, characterized in that said non-fixed data is a random number.

10. Method according to any one of claims 1 to 9, characterized in that said method is implemented before an execution of said first executable code (5).

11. Method according to any one of claims 1 to 9, characterized in that said method is implemented during the execution of said first executable code (5).

12. The method of claim 11, characterized in that said method is triggered by said first executable code (5).