Abstract: A method of verifying that a first device and a second device are physically interconnected is disclosed. The method is performed by a verifier and includes sending a challenge R1 to the first device, for use as basis for input to a first physical unclonable function, PUF, —part of the first device, receiving, a response, RES1, from the second device, the response RES1 being based on an output of a second PUF part of the second device, and verifying that the first device and the second device are interconnected for the case that the received response, RES1, and an expected response fulfills a matching criterion. A method in a first device and a method in a second device and corresponding devices, computer programs and computer program products are also disclosed.

Abstract: A method (40) is provided for performing a trustworthiness test on a random number generator, RNG, (20) comprising a physical unclonable function, PUF-module (21). The trustworthiness test is implemented as a known answer test, KAT, and the method (40) comprises: receiving (41), in the PUF-module (21), an input based on test data, T, received from a verifier (11) provided with at least one test data-test result pair, (T, R), providing (42) an output from the PUF-module (21), determining (43) a test result, R?, based on the output from the PUF-module (21), and providing (44) the test result, R?, to the verifier (11). A random number generator (20), computer program and computer program products and a method performed by or in a verifier are also provided.

Abstract: A method performed by a device for protecting data is provided. The method comprises inputting, to a Physically Unclonable Function, PUF, of the device, a challenge; obtaining, from the PUF, a response; and protecting the data by using the response. A device, a method in an encryption unit, computer program and computer program product are also provided.

Abstract: A method (40) of generating a pseudonym associated with a communication device (11) is disclosed. The method (40) is performed in a network node (13) of a communications system (10) and comprises generating (41) a pseudonym embryo based on one or more elements of a sequence (S1, S2, . . . , Sn), obtaining (42) the pseudonym as output of a masking operation applied to the pseudonym embryo, wherein the masking operation comprises a one-to-one mapping, and transmitting (43) the pseudonym to the communication device (11). A corresponding network node (13), computer program and computer program product are also disclosed.

Abstract: The disclosure relates to a method (20) for a serving device (3) of establishing a computational puzzle for use in communication between a client device (2) and the serving device (3). The method (20) comprises establishing (21), in the serving device (3), the computational puzzle (p) based on a key shared by the client device (2) and the serving device (3) and on a solution (s?, s?) to the computational puzzle (p). Further method (30) in a serving device is provided, methods (60, 70) for client devices (2), serving devices (3), client devices (2), computer programs and computer program products.

Abstract: A method (400) of generating a cryptographic checksum for a message M(x) is provided. The method is performed by a communication device, such as a sender or a receiver, and comprises calculating (405) the cryptographic checksum as a first function g of a division of a second function of M(x), ƒ(M(x)), modulo a generator polynomial p(x) of degree n, g(ƒ(M(x))mod p(x)). The generator polynomial is calculated (403) as p(x)=(1?x)·P1(x), and P1(x) is a primitive polynomial of degree n?1. The primitive polynomial is selected (402), based on a first cryptographic key, from the set of primitive polynomials of degree n?1 over a Galois Field. By replacing a standard checksum with a cryptographic checksum, an efficient message authentication is provided. The proposed cryptographic checksum may be used for providing integrity assurance on the message, i.e., for detecting random and intentional message changes, with a known level of security.

Abstract: A method of verifying that a first device and a second device are physically interconnected is disclosed. The method is performed by a verifier and includes sending a challenge R1 to the first device, for use as basis for input to a first physical unclonable function, PUF,—part of the first device, receiving, a response, RES1, from the second device, the response RES1 being based on an output of a second PUF part of the second device, and verifying that the first device and the second device are interconnected for the case that the received response, RES1, and an expected response fulfills a matching criterion. A method in a first device and a method in a second device and corresponding devices, computer programs and computer program products are also disclosed.

Abstract: A method (40) is provided for performing a trustworthiness test on a random number generator, RNG, (20) comprising a physical unclonable function, PUF,-module (21). The trustworthiness test is implemented as a known answer test, KAT, and the method (40) comprises: receiving (41), in the PUF-module (21), an input based on test data, T, received from a verifier (11) provided with at least one test data-test result pair, (T, R), providing (42) an output from the PUF-module (21), determining (43) a test result, R?, based on the output from the PUF-module (21), and providing (44) the test result, R?, to the verifier (11). A random number generator (20), computer program and computer program products and a method performed by or in a verifier are also provided.

Abstract: The disclosure relates to a method (30) for a network node (6, 7, 8) of a wireless network (1) of providing a device (5, 9) access to the wireless network (1). The method (30) comprises receiving (31), from a device (5, 9), an access request comprising a preamble; establishing (32), in response to the access request, a computational puzzle based on the received preamble; and sending (33) the computational puzzle to the device (5, 9). A corresponding method in a device is also disclosed, as are a network node (6, 7, 8), device (5, 9), computer programs and computer program products.

Abstract: A method (20) performed by a device (1) for protecting data is provided. The method (20) comprises inputting (21), to a Physically Unclonable Function, PUF, (3), of the device (1), a challenge; obtaining (22), from the PUF (3), a response; and protecting (23) the data by using the response. A device (1), a method in an encryption unit, computer program and computer program product are also provided.

Abstract: A technique for generating a keystream (128) for ciphering or deciphering a data stream (122) is provided. As to a method aspect of the technique, a nonlinear feedback shift register, NLFSR (112), including n register stages implemented in a Galois configuration is operated. At least one register stage of the implemented n register stages is representable by at least one register stage of a linear feedback shift register, LFSR. A first subset of the implemented n register stages is representable by a second subset of a second NLFSR. A number of register stages receiving a nonlinear feedback in the second NLFSR is greater than one and less than a number of register stages receiving a nonlinear feedback in the implemented NLFSR. The keystream (128) is outputted from a nonlinear output function (118). An input of the nonlinear output function (118) is coupled to at least two of the implemented n register stages of the NLFSR (112).

Abstract: A method and arrangements for enabling authentication of a communication device is suggested, where a network node, capable of operating as an authentication server does not have to store all state related information relevant for a roundtrip of an authentication session. Instead of storing all this information, at least a part of it is provided to the authenticator or the communication unit, for later retrieval in a subsequent response. Based on the state related information provided in the response, the network node is capable of reproducing a state associated with a respective roundtrip. By repeating the mentioned process for a required number of roundtrips, an authentication session can be executed, where less state related information need to be stored at the mentioned network node.

Abstract: A method (500) of generating a cryptographic checksum for a message M(x) is provided. The method comprises pseudo-randomly selecting (502) at least two irreducible polynomials pi(x). Each irreducible polynomial pi(x) is selected based on a first cryptographic key from the set of irreducible polynomials of degree ni over a Galois Field. The method further comprises calculating (503) a generator polynomial p(x) of degree n=formula (I) as a product of the N irreducible polynomials formula (II), and calculating (505) the cryptographic checksum as a first function g of a division of a second function of M(x), ƒ(M(x)), modulo p(x), i.e., g(ƒ(M(x)) mod p(x)). By replacing a standard checksum, such as a Cyclic Redundancy Check (CRC), with a cryptographic checksum, an efficient message authentication is provided. The proposed cryptographic checksum may be used for providing integrity assurance on the message, i.e., for detecting random and intentional message changes, with a known level of security.

Abstract: A method (500) of generating a cryptographic checksum for a message M(x) is provided. The method comprises pseudo-randomly selecting (502) a generator polynomial p(x) from the set of polynomials of degree n over a Galois Field and calculating (504) the cryptographic checksum as a first function g of a division of a second function of M(x), ƒ(M(x)), modulo p(x), g(ƒ(M(x))mod p(x)). The generator polynomial p(x) is pseudo-randomly selected based on a first cryptographic key. By replacing a standard checksum, such as a Cyclic Redundancy Check (CRC), with a cryptographic checksum, an efficient message authentication is provided. The proposed cryptographic checksum may be used for providing integrity assurance on the message, i.e., for detecting random and intentional message changes, with a known level of security. Further, a corresponding computer program, a corresponding computer program product, and a checksum generator for generating a cryptographic checksum, are provided.

Abstract: A method and arrangements for enabling authentication of a communication device is suggested, where a network node, capable of operating as an authentication server does not have to store all state related information relevant for a roundtrip of an authentication session. Instead of storing all this information, at least a part of it is provided to the authenticator or the communication unit, for later retrieval in a subsequent response. Based on the state related information provided in the response, the network node is capable of reproducing a state associated with a respective roundtrip. By repeating the mentioned process for a required number of roundtrips, an authentication session can be executed, where less state related information need to be stored at the mentioned network node.

Abstract: A method (40) of generating a pseudonym associated with a communication device (11) is disclosed. The method (40) is performed in a network node (13) of a communications system (10) and comprises generating (41) a pseudonym embryo based on one or more elements of a sequence (S1, S2, . . . , Sn), obtaining (42) the pseudonym as output of a masking operation applied to the pseudonym embryo, wherein the masking operation comprises a one-to-one mapping, and transmitting (43) the pseudonym to the communication device (11). A corresponding network node (13), computer program and computer program product are also disclosed.

Abstract: A method and arrangements for enabling authentication of a communication device is suggested, where a network node, capable of operating as an authentication server does not have to store all state related information relevant for a roundtrip of an authentication session. Instead of storing all this information, at least a part of it is provided to the authenticator or the communication unit, for later retrieval in a subsequent response. Based on the state related information provided in the response, the network node is capable of reproducing a state associated with a respective roundtrip. By repeating the mentioned process for a required number of roundtrips, an authentication session can be executed, where less state related information need to be stored at the mentioned network node.

Abstract: A method of authorizing a message received at a node in a wireless network is disclosed. The message from a sender device is formed by a plurality of symbols and includes a first message integrity indicator located at a predetermined distance from the start of the message such that further symbols of the message are included after the first message integrity indicator. The position of the first message integrity indicator in the message is determined, and a cryptographic operation is performed on at least some of the symbols of the message before the first message integrity indicator so as to generate a second message integrity indicator before the first message integrity indicator is received. The first and second message integrity indicators are compared, and an indication that the message is not authorized is provided if the second message integrity indicator does not match the first message integrity indicator.

Abstract: The disclosure relates to a method (20) for a serving device (3) of establishing a computational puzzle for use in communication between a client device (2) and the serving device (3). The method (20) comprises establishing (21), in the serving device (3), the computational puzzle (p) based on a key shared by the client device (2) and the serving device (3) and on a solution (s?, s?) to the computational puzzle (p). Further method (30) in a serving device is provided, methods (60, 70) for client devices (2), serving devices (3), client devices (2), computer programs and computer program products.

Abstract: Electronic devices (320) are provided which comprise a digital logic circuit (101) and a test module (322) adapted to receive test parameters from a remote test management device (310), generate test patterns based on the test parameters, apply the test patterns to the digital logic circuit, receive test responses from the digital logic circuit, compact the test responses into a test signature, and either transmit the test signature to the remote test management device or determine a test result based on a comparison of an expected signature received from the remote test management device with the test signature.