Classifications

• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07F—COIN-FREED OR LIKE APPARATUS
  • G07F7/00—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus
  • G07F7/08—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus by coded identity card or credit card or other personal identification means
  • G07F7/10—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus by coded identity card or credit card or other personal identification means together with a coded signal, e.g. in the form of personal identification information, like personal identification number [PIN] or biometric data
  • G07F7/1008—Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
  • G06Q20/00—Payment architectures, schemes or protocols
  • G06Q20/30—Payment architectures, schemes or protocols characterised by the use of specific devices or networks
  • G06Q20/34—Payment architectures, schemes or protocols characterised by the use of specific devices or networks using cards, e.g. integrated circuit [IC] cards or magnetic cards
  • G06Q20/341—Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
  • G06Q20/00—Payment architectures, schemes or protocols
  • G06Q20/38—Payment protocols; Details thereof
  • G06Q20/40—Authorisation, e.g. identification of payer or payee, verification of customer or shop credentials; Review and approval of payers, e.g. check credit lines or negative lists
  • G06Q20/409—Device specific authentication in transaction processing
  • G06Q20/4097—Device specific authentication in transaction processing using mutual authentication between devices and transaction partners
  • G06Q20/40975—Device specific authentication in transaction processing using mutual authentication between devices and transaction partners using encryption therefor
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07F—COIN-FREED OR LIKE APPARATUS
  • G07F7/00—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus
  • G07F7/08—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus by coded identity card or credit card or other personal identification means
  • G07F7/10—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus by coded identity card or credit card or other personal identification means together with a coded signal, e.g. in the form of personal identification information, like personal identification number [PIN] or biometric data
  • G07F7/1016—Devices or methods for securing the PIN and other transaction-data, e.g. by encryption

Definitions

• the present invention relates to the field of secure security modules comprising at least one central unit and two memory areas.
• This memory is of ROM type, that is to say that it is read only.
• this program will check the second memory area which is of the rewritable type, in general of the EEPROM, NVRAM or Flash type.
• This verification can be done in several ways such as the calculation of a footprint (CRC, Hash) and comparison of this footprint with a value stored in this same area.
• this first boot zone in addition to a read-only memory (ROM) part, includes a rewritable memory part which is subject to the same security conditions.
• ROM read-only memory
• the execution of the verification program can be carried out from the second zone.
• the latter is divided into a verification part and user part.
• the verification of the user program is carried out on the basis of the data of the first zone, namely on the basis of a first key which is generally stored in this first zone and which makes it possible to verify the fingerprint of the data of the second zone.
• the second zone contains data constituting the program and a signature which is encrypted by this first key.
• the verification program which can be either in the first zone or in a verification part of the second zone, calculates a unique fingerprint (Hash, CRC) on the data to be verified.
• CRC unique fingerprint
• the second zone contains the fingerprint encrypted by a key which is initially stored in the first zone.
• This key is used to decrypt the encrypted fingerprint and the result obtained is compared with the calculated fingerprint.
• This key can be in the first zone either in final form (ROM) or in programmed form (EEPROM or Flash).
• ROM final form
• EEPROM or Flash programmed form
• programming is done in the factory or in an authorized center, the program in the first zone accepts this programming provided that no key is already in this memory location.
• This key can be of symmetric type and therefore secret or can be of asymmetric type.
• this key can be in a memory zone other than the first zone because even if a third party were to discover this key, it would not be able to sign a set of modified data because it must necessarily do so using the corresponding private key. This key obviously does not come out of the management center which is in charge of preparing data updates.
• the data in the second memory area can represent either one or more programs, or important data such as rights or decryption keys, or a mixture of the two.
• this third party From knowledge of the content of the second memory area, this third party has the keys used to manage the various rights and access to the services that this processor controls.
• the object of the present invention is to provide a method for restoring the security of such a secure assembly after the content of the second memory area has been read by a third party.
• This object is achieved by a method of generating a security key carried out by a secure module comprising a central unit, a first memory area with conditional access and at least a second memory area containing all or part of the user program, characterized in that it comprises the following stages:
• this new key is generated without the data of the second zone being necessarily verified. If these data have been modified, the root key will simply be false and the future decryption of a transmission key with this key will not give the correct result.
• This root key therefore depends on the one hand on the download or content of the second memory (or data) and on a key stored in a region inaccessible to a third party.
• the factory key is replaced by a secret program stored in the first zone and which calculates, according to a secret algorithm, a fingerprint on all or part of the data of the second zone.
• a secret program stored in the first zone and which calculates, according to a secret algorithm, a fingerprint on all or part of the data of the second zone.
• the manipulation of data (mixture, multiplication, division, EXOR etc.) of the second zone according to a particular algorithm makes it possible to determine the root key.
• the MOD module is a secure processor module. As such, it has at least two memory zones, namely the first zone Z1 and the second zone 'Z2.
• the first zone consists of all or part of the ROM memory, therefore not rewritable.
• a part may include memory places in RAM or EEPROM for variables among others. It is said to be conditional access because it cannot be freely accessible, in particular during the execution of a program in the second zone.
• the second zone Z2 will contain the operating program and the data. This area is made up of non-volatile memory but with the possibility of writing such as EEPROM. Zone Z2 can also contain volatile memory such as RAM. In fact, this area is generally not homogeneous and can include several memories of the ROM, RAM, EEPROM, NVRAM or Flash type.
• zone 2 a first part of zone 2 called the Z2A work zone which will be used for operations relating to the generation of the root key.
• the Z2B user area is a schematic view of the part containing the operating program or programs. Depending on the implementation, it is possible to include variables such as security keys for example.
• the CPU processor is automatically directed to the first zone Zl during an engagement or a restart (reset). This is where the first security operations are carried out.
• the initialization program launched at startup calculates a fingerprint on the agreed part of the data to be checked. This part is defined by pointers which are contained in the second memory area. An illustration of the mechanism of portions of the Z2B user area is contained in Figure 2.
• the data forming the imprint can be taken into account on all or part of the user area. In practice, this imprint will preferably be calculated on the program part and not on the data part (viewing rights for example) because the latter may be modified during the use of the user program.
• the fingerprint determination program initialized at startup calculates this fingerprint on the agreed part of the data to be checked. This part is defined by pointers which are contained in the second memory area, in particular in the DES portion of FIG. 2.
• this imprint is produced by a unidirectional operation which is a mathematical application H from a source set to an object set, in which each element x of the source set is assigned an image H (x).
• H (x) H (x)
• the user area Z2B in Figure 1 is divided into several portions PA, PB and PC. These portions are not contiguous in this example and are separated by PI portions which are not involved in the calculation of the footprint.
• the information describing these different portions is contained in the DES portion which is also part of the user zone Z2B. It contains the indications of memory locations participating in the calculation of the control information. These indications can be either in the form 'start pointer' and 'length' or 'start pointer' and 'end pointer'.
• the I / O block illustrates the means of communication to the outside of the MOD module, means which are essential for using the cryptographic functions and the rights stored in the memory Z2B. It is also through this that data is accidentally extracted from the zone Z2 by a fault as described above.
• Figure 3 the step of generating the root key is shown schematically.
• the DTA data which, according to the example in FIG. 2, consist of the PA, PB and PC portions, are used to calculate by the processor the imprint which is in our case Hash control information.
• To calculate the root key RK we will use this control information H and a factory key MK2 to obtain this root key RK via an encryption module ENC.
• This secret key will be of symmetric type (or use symmetrically by the management center) because otherwise, the resulting root key would not be the same in the management center and in the MOD module.
• the factory key is replaced by a secret algorithm (RTN) which is stored in the first zone Z1. It can be copied from this first zone to the Z2A working zone during the initialization phase if necessary.
• RTN secret algorithm
• This algorithm mixes all or part of the DTA data in a particular mode in order to obtain a single result dependent on this data.
• This mixture can implement different arithmetic operations such as multiplication, Exor etc.
• the place of execution of these process steps is not decisive.
• the program in the boot area can simply copy the factory key to a temporary memory area and the program for generating the root key, called a system program, can be contained in the Z2A work area.
• the important thing is to store this factory key in the first zone Zl in order to make it inaccessible during normal execution of the user program.
• the management center which is in charge of security, is preparing new software in order to remedy a known defect such as a counterfeiter attack aimed at extracting data from the zone Z2.
• This new software is signed, that is to say that the Hash function is calculated on this data and the result is encrypted with the private key MK1.
• the program existing in the Z2B user area processes the incoming data and decrypts the messages using the system transmission key (s).
• the data is then stored in the locations provided for this purpose. Once this download is complete, the processor activates a restart function. This allows it to check all newly stored data.
• This verification generally relates to all of the stored programs and this verification is carried out according to the steps described above. If we consider the hypothesis that a third party has an insecure MOD module, the first memory area Z1 does not exist (or is blank) and the processor immediately starts in the second area Z2. The new program received from the management center is decrypted by the third party and the user area is therefore identical to that of a secure processor with dual memory areas.
• the root key is generated and is used to decrypt the new transmission key.
• the dummy module does not have this root key and cannot decrypt the transmission key. From this moment, the messages exchanged between the management center and the security module are no longer accessible to the fictitious module. If the latter tries to find the root key by an attack such as the one that allowed him to obtain the content of the second zone, this attack no longer works because the purpose of this new software is precisely to remedy this type of flaw .
• the secure module regains the level of security preceding the attack which allowed the data to be extracted.
• access to the first zone Z1 is made when the microprocessor is started or after a verification mechanism.
• the memory area Z1 with conditional access can only be used to provide the secret information necessary for the formation of the root key.
• the program of the use zone Z2 only opens access to the first zone Zl to read the information for the calculation of the root key. During these operations, the duration of visibility of the first zone will be limited to the time necessary to reading then this area will be made inaccessible.
• the factory key is in fact a set of keys. Each time a root key is generated, a factory key is deactivated.
• the selection of the key to be used can be done in different ways, namely: [66] - on command from the management center, that is to say by a descriptor in the DES definition data, [67] - in using the last n bits of the fingerprint (for example 3 bits) which allow to choose among the keys (eg the 8 keys) stored.

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• General Business, Economics & Management (AREA)
• Theoretical Computer Science (AREA)
• Strategic Management (AREA)
• Computer Security & Cryptography (AREA)
• Finance (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Computer Networks & Wireless Communication (AREA)
• Storage Device Security (AREA)

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• 2004
  • 2004-05-19 US US10/848,014 patent/US7725740B2/en active Active
  • 2004-05-27 WO PCT/IB2004/050794 patent/WO2004107283A1/fr active Application Filing
  • 2004-05-27 EP EP04735073A patent/EP1627362A1/de not_active Ceased
  • 2004-05-27 CN CN2004800147231A patent/CN1795471B/zh not_active Expired - Fee Related

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