FR2817107A1 - Method for securing financial calls made through mobile telephones, comprises use of mother and diversified keys located at mobile telephone and server and accessed by personal identification number - Google Patents

Abstract

A WAP server (3) receives a user request and asks a library (4) for a certificate request which is sent to the user mobile (2). An applet in the user SIM card asks for the user identification and if correct unlocks access to a cryptographic key, calculates a dynamic certificate which depends on the message and key and sends it to the server which makes the service available if the certificate is valid

Description

<Desc / Clms Page number 1>

 Electronic signature on the GSM / GPRS and UMTS network.

1) Technical field of intervention This patent application is in secure transactions and in particular in the scope of electronic payment. It relates to electronic signature applications through a mobile terminal of the GSM nature or of assistant personnel if the latter includes a smart card reader.

 Statement of the problem To date, it is perfectly possible to authenticate a person using their smart card, secure tokens, voice or digital fingerprint, but this requires dedicated transactional or banking infrastructure (PC with card reader. chip, payment terminal ..). This requires a special investment.

The objective of the concept is to offer authentication of the general public type through existing GSM mobiles, using the SIM card integrated into the terminal. More than half of Electronic Commerce over the years will go through mobile terminals. To date, there is no simple solution offering strong user authentication.

Although the SIM card is identified by the telecommunications operator for each communication, it is not sufficient in terms of security to enter the new services offered by the Mobile Internet.

The concept of transactional security is established between two points, on the one hand a software machine integrated into the SIM card allows authentication on the fly on several service providers and on the other a recognition server, calculates and compares the signatures received.

The SIM card integrates different applications with security levels adapted to each service.

The originality of this operation is that a smart card can calculate electronic signatures on the fly according to keys of variable length and cohabiting on the same card.

Possible services:

<Desc / Clms Page number 2>

 . Secure access to a range of WAP services (remote banks, stock market orders, reservations, ticketing applications, etc.) Secure access to a voice service (messaging, e-mail, text to speech) Reloading of prepaid cards for services operators, B to B applications, B to C, B to E ....

sécurisation simultanée de multiples applications en assurant néanmoins leurs étanchéités. . Secure access to a corporate service portal (WEB site) Private payments Applications Remote Sales The application meets the need by integrating within the mobile phone, a flexible security solution, independent of the protected application, and supporting the

simultaneous securing of multiple applications while ensuring their watertightness.

It allows strong authentication of the client, ie the certainty that the subscriber who accesses the service is an authentic subscriber, authorized to carry out this access.

dialogue par SMS avec l'applet. To our knowledge, there are no services using these concepts on the market. 2 Description of an application Components of the offer The product offer consists of 1. software (applets), suitable for all active SIM card versions on the market 2. a certification library used by a server allowing the

dialogue by SMS with the applet.

. le calcul sur le téléphone mobile de certificats dynamiques (utilisables une seule fois, donc non re jouables), après saisie par l'usager un code porteur applicatif, . la modification des clés par des fonctions disponibles sur le mobile (fonction Over The Air) a la modification par l'usager de son code porteur application. It allows:

. the calculation on the mobile phone of dynamic certificates (usable only once, therefore not replayable), after entry by the user an application carrier code,. the modification of the keys by functions available on the mobile (Over The Air function) to the modification by the user of his application carrier code.

<Desc / Clms Page number 3>

3 Summary of authentication 3. 1 Analysis of authentication
Numerical references: $ # SIM card = 1 - Mobile terminal or client workstation = 2 # WAP or other information server = 3 # Certification library = 4 a Applets on SIM card = 5. User or end customer = 6. Application = 7 # Personal code = 8 # Control server memory area = 9 # SIM card memory area = 10 Mother key ID = 11 * Diversified key = 12 # GSM / GPRS / UMTS mobile phone network = 13 # Channel SMS or data signaling = 14 Let’s imagine that a WAP (Wireless Application Protocol) or other mobile service is protected by our system.

 The user (6) begins to consult the public pages of the service and requests to access the protected part of the site. The WAP information server (3) detects this request and initiates the authentication procedure: 1. It requests the certification library (4) to calculate a certificate request message intended for the client station (2) having made the request to a secure area. 2. It (3) sends the message obtained in an SMS to the GSM mobile (2), and waits for a response from the latter before satisfying its request.

<Desc / Clms Page number 4>

3. The message is received by the GSM mobile (2) and transmitted to the applet present on the customer's SIM card (l), in a manner transparent to the user (6).

4. The applet (5) is awakened and takes control of the mobile (2). It requests the user (6) to enter the carrier code which will allow him to access the service. The user (6) then enters their carrier code. 5. If the code is correct, it unlocks access to a cryptographic key within the SIM card (1). The applet (5) then calculates a dynamic certificate depending on the message received and the cryptographic key, and returns the certificate obtained in an SMS to the server (3). 6. The server (3) receives this message and provides it to the certification library (4) to be checked. 7. The library (4) indicates whether the received certificate is correct or not. The WAP server (3) can then decide what to do: send the requested page, send an error page, etc. In total, two SMS messages have enabled authentication of the client (6) with from the server (3). The content of the messages exchanged does not provide information to a third party, and above all does not allow re-play. The service is therefore only delivered to customers with the applet (5) and a key, that is to say authentic users (6). 3.2 Key management Key management is an essential element of the system since it allows the applet to be shared between several applications, while ensuring watertightness between them.

3.3 Sharing the system between several applications
The applet (5) manages up to 16 keys, identified by their index (0 to 15). Each key belongs to an application, and each application manages a specific carrier code, different from the CHVI requested when the mobile is powered up (2).

Example:
Application 1
Bearer code 1

<Desc / Clms Page number 5>

Clé 0
Application 2
Code porteur 2
Clé 3
Clé 4 On peut alors gérer plusieurs applications simultanément comme l'accès à un service de banques à distance (Application 1) et l'accès à un Intranet sécurisé (Application 2). L'usager saisit un code porteur différent selon le service auquel il accède, mais il a toujours la possibilité d'attribuer la même valeur à ses deux codes porteurs.

Key 0
Application 2
Bearer code 2
Key 3
Key 4 We can then manage several applications simultaneously such as access to a remote banking service (Application 1) and access to a secure Intranet (Application 2). The user enters a different carrier code depending on the service they are accessing, but they can always assign the same value to their two carrier codes.

An application can hold two keys within the same SIM card (1): the first to manage current certificates, and the second in reserve for future services.

It is then possible to have the certificates calculated with another key.

ont la clé 4.

Another use of multiple keys consists in managing several families of users of the same service, those who have key 3 have for example, more rights than those who

have the key 4.

3.4 Modification of the keys The values of the keys for calculating the certificates can be modified, by the use of a specific key, unique in the card, called the management key, and which is used only for this use. If this key is present on the server (in the certification library 4), it is then possible to change the value of a key with a given index. This key must therefore be held by a particular entity, manager of the system, and guarantor of its proper functioning.

3.5 Typing of keys Keys can be of two types: simple DES (56 bits) or triple DES (112 bits).

The former allow faster calculations but are weaker from a cryptographic point of view. The use of seconds generates slightly higher calculation times but with a higher cryptographic strength.

If the certification keys can be simple DES, it is recommended that the management key be triple DES.

306 Diversification of keys
All users of the same service have different key values. The key 0 of user A is not the same as the key 0 of user B. It is this particularity which makes it possible to be certain when checking a correct certificate that

<Desc / Clms Page number 6>

 the user who returned it is the correct one (if all the users had the same keys, they would all return the same certificate, which would make it difficult to distinguish them therefore to authenticate them).

l'ancien code, puis le nouveau. The keys stored in SIM cards are diversified keys. Only the certification library has the root keys of an application 3.7 Modification of codes
The user can modify their carrier codes via the mobile interface, by entering

the old code, then the new one.

Aujourd'hui, l'applet (5) fonctionne sur SMS, seul canal utilisable pour dialoguer avec une applet (5). 3. 8 Scalability

Today, the applet (5) works on SMS, the only channel that can be used to communicate with an applet (5).

Tomorrow, the use of faster protocols (GPRS) already planned by GSM standards and soon to be integrated into mobiles will allow much higher authentication performance, without jeopardizing the security architecture offered.

3. 9 Integration into an existing environment The heart of server-side security is the certification library (4). Developed in C ANSI it can be integrated into any environment.

It can be provided in several forms: - Source files that can be integrated by the client into their system.

9 Adaptation in another software environment (Windows DLL, Java API, etc ...). With a PC communicating by a proprietary protocol over IP.

Claims (1)

claims

 Electronic signature method using mobile telephony networks (13) of GSM / GPRS and UMTS type; said method being such that: - signatures on the fly are calculated, during a voice or data session, using, via a signaling channel (14) in particular an SMS or data channel, at least one mother key (11) and diversified keys from said mother key (12); said mother key and said diversified keys being respectively recorded:

 'in a memory area (9) of a protected server (3) and' in a memory area (10) of the SIM card (1) of a mobile phone (2); access to said memory area of the SIM card being controlled by a personal identification code (8).