EP2868032A2

EP2868032A2 - Use of a puf for checking authentication, in particular for protecting against unauthorized access to a function of an ic or a control device

Info

Publication number: EP2868032A2
Application number: EP13753119.0A
Authority: EP
Inventors: Rainer Falk
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2012-10-19
Filing date: 2013-08-13
Publication date: 2015-05-06
Also published as: DE102012219112A1; CN104782076A; WO2014060134A3; WO2014060134A2; US20150269378A1

Abstract

In order to check authentication using a physical unclonable function (6), an authenticator (3) comprises a PUF (6) and an authentication checking function (5). A challenge response pair (4A) comprising an item of challenge information (C) and an item of response information (R) is provided for the authenticator (3). The challenge information (C) is used as an input for the PUF (6) which generates a PUF response (PR) in response to the input of the challenge information (C). The PUF response (PR) and the response (R) are used for a comparison, wherein an enable signal (A) is provided on the basis of a result of the comparison.

Description

description

Use of a PUF for checking an authentication, in particular for protection against unauthorized access to a function of an IC or control unit

This invention relates to the technical field of checking authentication by means of a Physical Unclosable Function (PUF).

Authentication is a basic security mechanism. In general, a user or an object can be authenticated. Depending on this, a functionality may e.g. an IC, a controller, software, or a service reachable via a network can be activated or deactivated, e.g. accessing certain memory areas, a configuration and diagnostic function (e.g., JTAG), or activation of a particular functionality (e.g., battery charging with currents above a threshold).

Authentication can generally take place by means of a password or a cryptographic key or by means of biometric properties of a user (fingerprint,...) Or of a physical object (physical unclonable function). The authenticated points to know a password, a cryptographic key, or to exhibit a certain property. In general, authentication by possession of an object is also known, e.g. by possession of a door key or a badge.

Device authentication, eg of a semiconductor IC: A programmable logic device (in particular an FPGA) functions only or only without restriction if a specific hardware device (security IC) is detected as being present. This prevents simple copying of FPGA bitfiles because a copied bitfile is in a different hardware environment in which no or another security IC is available. is not workable there. An example is http: // www. maxim- ic. com / app-notes / index. mvp / id / 3826

Semiconductor ICs as well as e.g. Controllers have diagnostic interfaces to access internal functions during development, manufacturing, or repair. Access to such functionality must be protected in regular operation if sensitive information is accessible (e.g., reading stored keys). It is known to disable such interfaces when they are no longer needed (by burning a so-called security fuse). It is also known

Protect access to a diagnostic interface using cryptographic techniques (see, for example, (Honeywell: ENCRYPTED JTAG INTERFACE, WO2007005706, as well as US Pat

htt: // catt. poly edu / content / researchreviewl 0 SecurityExtensi onstoJTAG. df).

Physical Unclonable Functions (PUF):

An overview of Physical Unclonable Functions (PUF) can be found in the lecture notes

htt: // www. sec. in . tum. de / assets / teaching / ss 10 / sms / sms-kap6-rfid- 16x.12 pdf) ■

Physical Unclonable Functions are known to reliably identify objects based on their intrinsic physical properties. A physical property of an object (eg a semiconductor IC) is used as an individual "fingerprint." Authentication of an object is based on the fact that, depending on a challenge value, a corresponding response value is returned by a PUF function defined by physical properties Physical Unclonable Functions (PUF) provide a space-saving and thus cost-effective way of authenticating a physical object based on its intrinsic physical properties by adding a corresponding response value to a given challenge value by the PUF, depending on the object-specific physical properties of the object An examiner who selects an object In the case of known ChallengeResponse pairs, a similarity comparison of the present and the response values provided by the authenticated object can identify the object as the original object.

Further applications of a PUF are known, in particular the chip-internal determination of a cryptographic key by means of a PUF. The determined cryptographic key is used within the chip for calculating a cryptographic operation.

The PUF raw data (response) generally still needs to be reworked to compensate for statistical variations in the PUF response to a particular challenge (e.g., by forward error correction or feature extraction, as in conventional fingerprint authentication).

By Yousra M. Alkabani, Farinaz Koushanfar: Active Hardware Metering for Intellectual Property Protection and Security, 16th USENIX Security Symposium, 2007,

http: // www. usenix. org / event / sec07 / tech / full_papers / alkabani / a lkabani.pdf is known to prevent the overbuilding of semiconductor ICs by means of a PUF by modifying the state machine needed to operate the IC to a large number The start state is determined by means of a PUF, ie the IC starts execution in a start state dependent on random, instance-specific properties .Only the designer of the IC, who knows the design specification of the state machine, For example, for a particular IC, it may be practical to determine a path from the random initial state to a start state required for the use of the functionality, and thus to program a fabricated IC.

An advantage of PUFs is that a PUF structure is changed during a physical manipulation and thus tamper protection is achievable. In addition, PUFs also applicable if a device does not have memory to permanently store a cryptographic key (this either requires special manufacturing processes, eg for flash memory, or a backup battery for SRAM memory cells).

Different physical implementations of a Physical Unclonable Function are known. Many PUFs can be implemented easily and space-saving on an IC (digital or analog). There is no need for a permanent keystore and no implementation of cryptographic algorithms.

It is known as PUF replenishment that a PUF authentication server determines challenge-response pairs during operation and stores them for future authentication (check processes) (see http://ip.com/lPCOM/000127000).

Title: CRP replication protocol for PUFs).

It is known to perform a PUF-based authentication, wherein for the first time challenge-response pairs of another, trustworthy entity are used to acquire reference data for further challenge-response pairs that can be used for later authentications (see FIG

US20090083833, especially sections 6 and 15).

In the case of authentication, there is generally an authenticator (also called examiner or authenticator) and an authentication object (also called an authenticator, examinee, or supplicant). It is known in the art that the authenticator uses a PUF to authenticate himself.

FIG. 1 shows an authentication system 80 according to the prior art. The authentication check function 85 of a tester 83 selects a challenge c in the prior art and transmits it to the test object 82. The test object 82 receives the challenge c and uses a PUF 86 of the test object 82 to determine a response value r. The response value r becomes provided to the examiner 83. It determines here, by means of a list 87 of stored challenge-response pairs (CR pairs), whether the response r provided by the test object 82 is valid. This can be done, for example, by a similarity comparison of the response value r provided by the test object 82 with a reference response value stored for the challenge value c used. For example, identical response values and response values with a Hamming distance of max. 2 are accepted as valid (ie a maximum of 2 bits may be different). If the response r provided by the device under test 82 is accepted as valid, an Accept signal a is provided, ie the device under test 82 is accepted as valid. It can, for example, an RFID tag, a battery or similar. be recognized as valid (original product). However, a disadvantage of this system is that the examiner is costly

Memory components needed and attack surface for reading the CR pairs offers, which then allow attacks on the system protected by the examiner. There is a need for authentication that is sufficiently attack-resistant and cost-effective and easy to use. The present invention has for its object to meet this need. This object is achieved by the solutions described in the independent claims.

Advantageous embodiments of the invention are specified in further claims.

According to a first aspect of the invention is a

A method for checking an authentication of an authentication object by means of an authenticator is disclosed. The authenticator comprises a physical unclonable function, referred to below as PUF, and an authentication check function. The authenticator is provided with a challenge-response pair. The challenge-response pair comprises a challenge information, also called a challenge below, and a Response information, also called response below. The response is provided to the authenticator by the authentication object. The challenge information is used as input to the PUF. The PUF generates a PUF response to the input of the challenge information. The PUF response and response are used for comparison. Depending on a result of the comparison, a release signal is provided. According to a further aspect, the invention relates to an authentication device for authenticating an authentication object. The authenticator comprises a PUF, an authentication check function and a detection means for detecting a challenge-response pair. The challenge-response pair comprises a challenge information and a response

Information. The detection means is configured and / or adapted to receive the response information from the authentication object. The authenticator is configured and / or adapted to transfer the response to the authentication check function, to use the challenge information sent by the authentication object as input for the PUF, and also to send a PUF response generated by the PUF to the authentication check function to hand over. The authentication check function is configured and / or adapted to use the PUF response and the response for a comparison. The comparison provides an enabling signal depending on the result of the comparison.

According to a further aspect, the invention also relates to an authentication system which comprises the above-described authenticator and an authentication object, wherein the authentication object is configured and / or adapted to make the response available to the authenticator. The invention will be explained in more detail with reference to the drawing, for example. Showing: 1 shows a system for authenticating an authentication object according to the prior art; and

Figure 2 is a system for authenticating an authentication object based on its preferred embodiments of the invention will be explained below.

FIG. 2 shows an authentication system 1, which comprises an authentication object 2 and an electronic part 9. The electronic part 9 comprises an authenticator 3, and the authentication object 2 comprises a memory area 7. In the memory area 7, challenge-response pairs 4A, 4B, 4C are stored. Each of the challenge-response pairs 4A, 4B, 4C comprises a challenge information C, C2, C3, hereinafter also called challenge value C, C2, C3, or simply challenge C, C2, C3, and one to one of the Challenge associated response information R, R2, R3, hereinafter also Ronse value R, R2, R3, or Response R, R2, R3, called. The authenticator 3 comprises an authentication check function 5, a physical unclonable function 6, also referred to below as PUF 6, and a detection means 10 for detecting challenge-response pairs 4A, 4B, 4C. In order to verify the authenticity or the authorization of the authentication object 2, a challenge-response pair 4A is made available to the authenticator. In the preferred exemplary embodiment illustrated in FIG. 2, the challenge-response pair 4A is sent to the authenticator 3 by the authentication object 2. The authenticator 3 uses the challenge information C as an input for the PUF 6, which generates a PUF response PR on the input of the challenge information C. The PUF response PR and the response R are used for a comparison, wherein a release signal A is provided depending on the result of the comparison.

However, according to further preferred embodiments of the invention, it is not necessary for the authentication object to be 2 stores the challenge-response pairs 4A, 4B, 4C. It can query these from a database, or calculate them by means of a calculation model of the PUF 6. Likewise, it is not necessary for the authentication object to provide the entire challenge / response pair 4A of the PUF. It is sufficient if the response R is provided by the authentication object 2 to the authenticator 3. The challenge information C can also be selected by the authenticator 3 or by a third instance.

According to the preferred embodiment, a match measure is determined in the context of the comparison. The match score is compared to a threshold. Preferably, the enable signal A is provided if the determined measure of conformity reaches or exceeds the threshold value.

In the context of the comparison, for example, it can be checked whether:

a) the response R sufficiently matches the PUF response PR; or

b) for repeated input of the challenge information C into the PUF 6, the PUF responses generated by the PUF 6 PRi sufficiently agree with the response R; or

c) for inputs of different Challenge Information C, C2, C3 into the PUF 6, the PUF responses generated by the PUF 6 PR, PR2, PR3 sufficient with the corresponding Challenges C, C2, C3 Responses R, R2, R3 to match .

The Authentisierungsobj ect 2 is therefore preferably designed and / or adapted to provide the authenticator 3 multiple Responses R, R2, R3 or Challenge-Response pairs 4A, 4B, 4C.

According to a further embodiment, the electronic part 9 is designed and / or adapted to be either in an open or in a restricted state. the. In the restricted state, a function of the electronic part is not or only partially usable. However, the enable signal A does not necessarily serve to limit a function of the electronic part 9, it can also be used to limit external functions, ie to limit the functions of other systems or components.

According to the preferred embodiment, the authentication object 2 also provides PUF correction data that the authenticator 3 uses to verify the provided response R, R2, R3 and the PUF response PR, PR2, PR3, PRi generated by means of the PUF 6. For this purpose, the detection means 10 is also designed and / or adapted to receive the PUF correction data from the authentication object (2).

Preferably, when the challenge-response pair 4A or the challenge-response pairs 4A, 4B, 4C is detected by the authenticator 3, identification information of the authentication object 2 is determined and dependent thereon is a cryptographic key for the encrypted transmission of responses R. , R2, R3, or for the encrypted transmission of challenge-response pairs 4A, 4B, 4C between the authenticator and the Authentisierungsobj ect or see between an unlockable function and the authentication object 2 determines. The communication could also take place between the unlockable function and the authenticated object (additional variant). Here, the authenticator 3 would determine a cryptographic key and provide the unlockable function.

According to a further preferred embodiment, depending on the challenge-response pair 4A provided to the authenticator 3 or depending on the challenge-response pairs 4A, 4B, 4C provided to the authenticator 3, the authenticator 3 generates a cryptographic key for the encrypted transmission of responses R, R2, R3, or for the encrypted transmission of challenge-response Pairs 4A, 4B, 4C between the authenticator 3 and the thentisierungsobj ect 2 or between an unlockable function and the Authentisierungsobj ect 2 determines. The challenge values C, C2, C3 or the challenge-response pairs 4A, 4B, 4C are thus used directly to determine a key. The identification information of the authentication object 2 can thus also be given by the challenge value or values C, C2, C3 or the challenge-response pair 4A, 4B, 4C (in addition to the customary variant that a user Name, a serial number or network address is used).

In order to determine the cryptographic key (s), the authenticator 3 comprises a cryptographic means 11.

In accordance with a further preferred embodiment, the authenticator 3 comprises a provisioning means 12 which is designed and / or adapted to provide further challenge-response pairs for future authentication after accepting the authentication object 2.

According to a further preferred embodiment, the inventive method comprises providing the Authentisierungsobj ectes 2 and 3 of the authenticator.

In accordance with a preferred embodiment of the invention, associated response values can be determined by means of the physical unclonable function PUF for selectable challenge values. For a given challenge value, in general, only several, but not bit-wise, identical response values are determined for several runs. A PUF may be illustratively considered the "fingerprint" of a hardware object Hitherto, according to the prior art, a PUF may be used to identify the object by its "fuzzy" fingerprint. It is also known internally to determine a cryptographic key from PUF responses using error correction methods and stored correction data. According to a preferred embodiment of the invention, a physical unclonable function PUF of an object is now not used as in the prior art for calculating a response provided to an external entity for examination in the context of an object authentication but for checking a received response or a challenge Response pair through the object. As a result, a PUF of an object (for example of a semiconductor IC such as a memory module, an FPGA or ASIC, or a so-called system on chip SoC) can not only be used as previously for authenticating the object by an outsider, but conversely, the object itself can the PUF of the object to authenticate an outsider and depending on a certain function unlock (eg memory access to a specific memory area, execution / start of a realized by the IC control algorithm or a functionality, test / diagnostic interface of the ICs (eg JTAG interface) Challenge-response pairs of a chip for future authentication processes can be detectable, for example, as long as the chip is in an open mode (eg security fuse not burned), so that they can be read out by an authorized user and stored in a database, for example - chert be, or it may possibly be determined a chip model, m with which the valid responses can be calculated for any challenge. Thereafter, the chip can be "lured", eg by burning a fuse, after which access to protected functionality is only possible after a valid response value has been provided. After granting access, the PUF can be used in one variant, In other words, according to a preferred embodiment, the PUF 6 is used in a dual fashion, namely by the authenticator 3. The PUF 6 does not realize an authentication function in the role of the device under test here . but an authentication verification in the role of the examiner. This makes it possible to use a simple and inexpensive realizable PUF 6 now for a whole new purpose.

According to the preferred embodiment, the PUF 6 is now used to test a provided Response R. In the example shown in FIG. 2, the test object 2 provides a charge-response pair C, R. The response value R is stored here. If authentication is successful, the authentication check function 5 provides an Accept signal A. This may enable a function of the tester 3 (e.g., diagnostic interface, configuration mode, feature enable). In a variant (not shown) the test specimen 2 can be provided by the examiner 3 with a message about the success or failure.

A comparator 7 of the authenticator 3 checks the response R provided by the authenticated 2 and the (expected) response PR determined by the PUF 6 of the authenticator 3 for consistency (sufficient similarity). Optionally, the internal PUF 6 of the authenticator 3 may be polled multiple times for the same challenge information C to obtain multiple PUF responses PRi for a particular challenge information C. As a result, a higher recognition rate can be achieved (response information PRi of the PUF 6 for a fixed batch value is not exactly identical to the bit, but only statistically similar). The challenge value C can be selected by the authenticating object 2 (test object), by the authenticator 3 (examiner) or by a third party. It is possible to use an identical challenge information C, but preferably a plurality of changing challenge information C, C2, C3.

In a variant, the test object 2 provides PUF correction data (helper data / fuzzy extractor parameters, eg parameters forward error correction) which the checker 3 uses to verify the provided response R and the response value PR determined by means of the physical PUF 6. In the initial acquisition of challenge-response pairs (hereinafter also referred to as CR pairs), the examiner 3 sets aside CR-

Pair or the response R associated with a specific challenge information C additionally provides correction data. In one variant, the correction data has a selectable parameter (e.g., a PIN or a password). This has the advantage that an authentication by means of a password,

PIN or similar is possible, wherein the password or the PIN is checked by means of a PUF and the correction data. The auditor 3 therefore does not have to store any check information, but instead can check a provided password by means of a PUF and provided data. During the initial detection of CR pairs, the tester 3 additionally provides correction data in addition to the CR pair or the response value R assigned to a specific challenge value C, wherein the response value R or the correction data is selected by a selectable parameter (PIN , Password) provided to the verifier 3. The examinee 2 then stores only a CR pair or correction data, but not the password or the PIN. In order to successfully perform an authentication, the password or PIN first has to be provided to the device under test 2, eg by a user via an input option, so that the authentication data required for successful authentication can be available to the device under test 2 and thus made available to the tester 3. The test object 2 can store CR pairs 4A, 4B, 4C of the authenticator 3, query from a database, or calculate the PUF 6 by means of a calculation model. For this purpose, the (physical) PUF 6 is measured in an initialization phase in order to determine the model parameters. In both cases (CR pairs, model parameters), this data has been collected and stored at an earlier point in time, eg during the manufacture of the authenticator. If the examinee 2 interrogates a CR pair from a database, then in a preferred variant, this query via a communication connection, eg via an IP / http connection. This can be protected by IPsec or SSL / TLS, for example. The examinee 2 authenticates itself, for example, by means of a password or a cryptographic key with respect to the database server. Only if the device under test 2 is authorized to release a functionality on an examiner component, a CR pair is provided to it for activating the functionality of the database server.

After a successful locking process of the authenticator 3, it can be used in a restricted operating mode. Thus, e.g. a diagnostic interface (JTAG, RS232, USB) may be disabled, certain functionality (e.g., access to a memory area, use of a stored key) may be inhibited. Only after provision of a C-R pair that can be successfully verified by means of the PUF 6, this functionality is unlocked. It can remain unlocked until a lock command is received, power is interrupted, or rebooted.

The described authentication can also be performed with further authentication methods, e.g. a conventional password check or a cryptographic challenge response

Authentication can be combined. Depending on the authentication variant used, a different functionality can be enabled. In another variant, several authentication must be passed successfully in order to enable a functionality of the auditor 3.

In one variant, the CR pair 4A or the response value R, which is transmitted to the verifier 3, is cryptographically encrypted. In this case, the verifier 3 uses a stored cryptographic key to decrypt the received C-R pair 4A and the received response R, respectively. The decrypted value is provided to the PUF 6 internally for review. When detecting CR pairs 4A, 4B, 4C for later use, an identification information of the device under test 2 can be determined by the tester 3 and dependent thereon a cryptographic key for encryption of CR

Pairs 4A, 4B, 4C or responses R, R2, R3. A given examinee 2 is thereby provided with C-R pairs 4A, 4B, 4C for later authentications tied to its identity. Another candidate with a different identity can not use these C-R pairs. This prevents easy copying of C-R pairs 4A, 4B, 4C and use by another device under test. In a later authentication of the test specimen by the examiner first his identity is detected and dependent on the key reconstructed in order to decrypt thus received by him C-R pairs or Responses.

The determination of the specimen-specific key may e.g. using a cryptographic Key Derivation Function (KDF), a cryptographic hash function. A DUT-specific key is derived from an unbound key (i.e., calculated by a one-way function). The original key used can be fixed, configurable, or it can be determined from a PUF (identical or different to the authentication verification PUU).

According to a preferred embodiment of the invention, an alternative to a password check is provided. For a password check the password or a password of the

Password dependent test parameters are stored. No memory is required, making it suitable for ICs that do not have the ability to store data permanently. Otherwise a memory would have to be provided (for example production-technically problematic) or

flammable fuses (which also represent a memory), an SRAM backup battery can be provided (battery problematic), or an external EEPROM memory can be used (cost, interface vulnerable to EEPROM).

Also, no crypto algorithm (cryptographic hash function or the like) must be provided to perform a cryptographic challenge-response protocol (chip area, power consumption).

Furthermore, no possibly readable password is present on the block (for example, not stored in clear text in the memory), where it could be readable by attacks.

Claims

claims

Method for checking an authentication of an authentication object (2) by means of an authenticator (3) comprising a Physical Unclonable Function (6), hereinafter called PUF (6), and an authentication check function (5), comprising the method the process steps:

Providing a challenge-response pair (4A) for the authenticator (3), wherein the challenge-response pair (4A) a challenge information (C), hereinafter also called challenge (C), and a response information ( R), also referred to below as the response (R), and wherein the response (R) is provided by the authentication object (2) to the authenticator (3);

Using the challenge information (C) as input to the PUF (6), which generates a PUF response (PR) upon entry of the challenge information (C);

Using the PUF response (PR) and the response (R) for a comparison, a release signal (A) being provided depending on a result of the comparison.

2. The method according to claim 1, wherein in the context of the comparison, a match measure is determined, which is compared with a threshold value, and wherein the enable signal (A) is preferably provided if the determined match score reaches or exceeds the threshold value.

3. The method according to any one of the preceding claims, wherein is checked in the context of the comparison whether:

a) the response (R) matches the PUF response (PR) sufficiently; or

b) for repeated input of the challenge information (C, C2, C3) into the PUF (6) the PUF responses (PRi) thus generated by the PUF (6) sufficiently coincide with the response (R); or

c) for inputs of different Challenge Information (C, C2, C3) into the PUF (6) which are thereby generated by the PUF (6). PUF responses (PR, PR2, PR3) sufficiently agree with the corresponding to the respective challenges (C, C2, C3) Responses (R, R2, R3).

4. The method according to any one of the preceding claims, wherein the Authentisierungsobj ect (2) in addition to the response (R) and the Challenge (C) the authenticator (3) provides.

5. The method according to any one of the preceding claims, wherein the Authentisierungsobj ect (2) comprises a chip with a memory area (7) in which the challenge-response pair (4A) is stored and / or the challenge-response pairs (4A , 4B, 4C) are stored.

6. The method according to any one of the preceding claims, wherein the Authentisierungsobj ect (2) provides a plurality of challenge-response pairs (4A, 4B, 4C) and / or stores them in the memory area (7).

7. Method according to one of the preceding claims, wherein the authenticator (3) is constituted by an electronic part (9), e.g. an integrated circuit or a controller is included, wherein the electronic part (9) is designed and / or adapted to be either in an open or in a restricted state, and wherein in the restricted state, a function of the electronic part is not limited or is usable.

8. The method according to any one of the preceding claims, wherein the Authentisierungsobj ect (2) PUF correction data provides that the authenticator (3) for verification of the provided response (R) and the PUF (6) generated by the PUF response (PR) used.

9. Method according to one of the preceding claims, wherein the authentication object (2) stores the challenge-response pair (4A) or the challenge-response pairs (4A, 4B, 4C). chert, queried from a database, or calculated by means of a calculation model of the PUF (6).

10. The method according to any one of the preceding claims, wherein when providing the challenge-response pair (4A) or the challenge-response pairs (4A, 4B, 4C) of the authenticator (3) identifies identification information of the Authentisierungsob- jektes (2) and preferably dependent thereon, a cryptographic key for the encrypted transmission of responses (R, R2, R3), or for the encrypted transmission of challenge-response pairs (4A, 4B, 4C) between the authenticator (3) and the authentication object (2 ) or between an unlockable function and the Authentisierungsobj ect (2).

11. Method according to one of the preceding claims, wherein, depending on the challenge-response pair (4A) provided to the authenticator or on the challenge-response pairs (4A, 4B, 4C) provided to the authenticator, the authenticator ( 3) a cryptographic key for the encrypted transmission of responses (R, R2, R3), or for the encrypted transmission of challenge-response pairs (4A, 4B, 4C) between the authenticator (3) and the Authentisierungsobj ect (2) or between an unlockable function and the Authentisierungsobj ect (2) is determined.

12. The method according to any one of the preceding claims, wherein the authenticator (3) after acceptance of the authentication object ejec (2) provides further challenge-response pairs for future authentication.

13. Authenticator (3) for authenticating a Authentisierungsobj ectes (2), comprising:

a Physical Unclonable Function (6), hereinafter PUF

(6) called;

an authentication check function (5); and a detection means (10) for detecting a challenge-response pair (4A), wherein the challenge-response pair (4A) a challenge information (C), hereinafter also called Challenge (C), and a response information ( R), hereinafter also referred to as response (R), and wherein the detection means (10) is designed and / or adapted to receive the response (R) from the authentication object (2); wherein the authenticator (3) is designed and / or adapted to transfer the response (R) to the authentication check function (5), and the challenge information (C) sent by the authentication object (2) is input to the PUF (6 ) and also to pass a PUF response (PR) generated thereon to the authentication check function (5); and

the authentication check function (5) is designed and / or adapted to use the PUF response (PR) and the response (R) for a comparison, a release signal (A) being provided depending on a result of the comparison.

14. Authenticator (3) according to claim 13, wherein the authentication check function (5) is configured and / or adapted to determine a match measure in the context of the comparison, which is compared with a threshold value, and preferably the authenticator (3) and / or is adapted to provide the enabling signal if the determined measure of conformity reaches or exceeds the threshold value.

15. Authenticator (3) according to claim 13 or 14, wherein the authentication check function (5) is designed and / or adapted to check in the context of the comparison whether:

a) the response (R) matches the PUF response (PR) sufficiently; or

b) for repeated input of the challenge information (C) into the PUF (6) the PUF responses (PRi) thus generated by the PUF (6) sufficiently coincide with the response (R); or c) for inputs of changing challenge information (C, C2, C3) into the PUF (6) the PUF responses (PR, PR2, PR3) thus generated by the PUF (6) are sufficiently provided with the responses (R, R2, 3) to match.

The authenticator (3) according to any one of claims 13-15, wherein the detection means (10) is further configured and / or adapted to receive the challenge (C) from the authentication object (2).

17. Authenticator (3) according to any one of claims 13-16, wherein the detection means (10) is also designed and / or adapted to receive from the Authentisierungsobj ect (2) PUF correction data, and these for verification of the provided response (R ) and the PUF response (PR) determined by the PUF (6).

18. Authenticator (3) according to any one of claims 13-17, wherein the authenticator 3 is configured and / or adapted, due to the detection of the challenge-response pair (4A) or due to a plurality of detected by the detection means Challenge-response pairs ( 4A, 4B, 4C) identify identification information of the Authentisierungsobj ectes (2) and preferably dependent on a cryptographic key for the encrypted transmission of responses, or for the encrypted transmission of challenge-response pairs between the authenticator (3) and the Authentisierungsobj ect ( 2) or between an unlockable function and the Authentisierungsobj ect (2) to determine.

19. Authenticator (3) according to any one of claims 13-18, comprising a crypto-agent 11, which is designed and / or adapted, depending on the detected challenge-response pair (4A) or depending on the detected challenge-response pairs ( 4A, 4B, 4C) a cryptographic key for the encrypted transmission of responses (R, R2, R3), or for the encrypted transmission of challenge-response pairs (4A, 4B, 4C) between the authenticator (3) and the Authentisierungsobj ect (2) or between a freely switchable function and the Authentisierungsobj ect (2) to determine.

20. Authenticator (3) according to any one of claims 13-19, comprising a provisioning means (12) which is designed and / or adapted to provide after accepting the Authentisierungsobj ectes (2) further challenge-response pairs for future authentication.

An authenticator (3) according to any one of claims 13-20, wherein the authenticator (3) is constituted by an electronic part (9), e.g. an IC or a control device is included, wherein the part is designed and / or adapted to be either in an open or in a restricted state, and wherein in the restricted state, a function of the electronic part is not or only partially usable.

22. Authentication system (1) comprising an authenticator (3) according to one of claims 12-19 and an authentication object (2) which is designed and / or adapted to provide the response (R) to the authenticator (3).

23. Authentication system (1) according to claim 22, wherein the authentication object (2) comprises a chip with a memory area (7) in which the challenge-response pair (4A) is stored.

24. Authentication system (1) according to claim 22 or 23, wherein the Authentisierungsobj ect (2) is configured and / or adapted to provide a plurality of challenge-response pairs (4A, 4B, 4C), or these in the memory area (7 ) save.

25. Authentication system (1) according to one of claims 22-24, wherein the authentication object (2) stores the challenge-response pair (s) (4A, 4B, 4C) from a data queries or calculated by means of a calculation model of the PUF.