Abstract:
A method is provided for authenticating a first entity and a second entity at a third entity. The first and third entities share a first secret key, and the second and third entities share a second secret key. The method includes steps of: dispatching by the third entity to the first entity of a challenge, calculation by the first entity, using the first secret key, of an authentication value; dispatching by the first entity to the second entity the authentication value, calculation by the second entity, using the second secret key, of an authentication response; dispatching by the second entity to the third entity of the authentication response; calculation by the third entity of an expected authentication response; and comparison of the authentication response received with the expected calculated authentication response.
Abstract:
A method is provided for authenticating a first entity and a second entity at a third entity. The first and third entities share a first secret key, and the second and third entities share a second secret key. The method includes steps of: dispatching by the third entity to the first entity of a challenge, calculation by the first entity, using the first secret key, of an authentication value; dispatching by the first entity to the second entity the authentication value, calculation by the second entity, using the second secret key, of an authentication response; dispatching by the second entity to the third entity of the authentication response; calculation by the third entity of an expected authentication response; and comparison of the authentication response received with the expected calculated authentication response.
Abstract:
A system, method, and data structure provide for securely synchronizing passwords and/or other information between systems. The password-related information is stored in the systems in a secure manner, and a user or some other, external agent participates actively in the transmission of a new password between systems. A password update file is communicated or shared between systems to synchronize passwords.
Abstract:
A system and a method for cryptographic reduced-coupon reloading are provided, where a coupon includes a pseudo-random number ri=PRFK(i), where i is an index for labeling the coupon, PRF is a predetermined pseudo-random function and K is a regeneration key, and a “reduced-coupon” xi=ƒ(ri), where ƒ is a predetermined one-way function, where: a candidate device and a second device acquire a common value of a token T, the candidate device transmits a verification value vT to the second device, the second device verifies whether the verification value is equal to PRF′Q(T), where PRF′ is a predetermined keyed pseudo-random function identical to, or derived from, the pseudo-random function PRF, where Q is an authentication key owned by the second device and known to the candidate device provided the candidate device is a legitimate reloading device, and if the verification is positive, one or several reduced-coupon(s) provided by the candidate device are stored in the second device.
Abstract:
A method and apparatus are provided for identifying and authenticating a radio tag by a radio reader. The tag forms part of a set of tags in a radio range of the reader and has selected a time slot from a set of available time slots. The method includes: a step of the reader sending a query message during the selected time slot; and a step of the reader receiving a reply message from the tag that selected the time slot. The reply message includes a random value selected by the tag. The tag stores authentication coupons and the reply from the tag received by the reader during the time slot contains, as a random value selected by the tag, a value that is a function of one of the coupons.
Abstract:
A system and a method for cryptographic coupon reloading are provided for, wherein a coupon comprises, on one hand, a pseudo-random number ri=PRFK(i), where i is an index for labeling the coupon, PRF is a predetermined pseudo-random function and K is a regeneration key, and, on the other hand, a “reduced-coupon” xi such that xi=ƒ(ri), where ƒ is a predetermined one-way function, characterized in that it comprises the following steps: a candidate device (1) and a second device (2) acquire a common value of a token T, said candidate device (1) transmits a verification value vT to the second device (2), the second device (2) verifies whether said verification value vT is given by vT=PRF′Q(T), where PRF′ is a predetermined keyed pseudo-random function identical to, or derived from, said pseudo-random function PRF, and where Q is an authentication key owned by the second device (2) and known to the candidate device (1) provided the candidate device (1) is a legitimate reloading device (1), and if the verification is positive, one or several reduced-coupon(s) provided by the reloading device (1) are stored in the second device (2). Application to second devices contained in RFID tags.
Abstract:
A method and apparatus are provided for identifying and authenticating a radio tag by a radio reader. The tag forms part of a set of tags in a radio range of the reader and has selected a time slot from a set of available time slots. The method includes: a step of the reader sending a query message during the selected time slot; and a step of the reader receiving a reply message from the tag that selected the time slot. The reply message includes a random value selected by the tag. The tag stores authentication coupons and the reply from the tag received by the reader during the time slot contains, as a random value selected by the tag, a value that is a function of one of the coupons.
Abstract:
An authentication method of a prover device by a verifier device using cryptographic coupons is provided, where a coupon includes a pseudo-random number ri, where i is an index for labeling the coupon, and a reduced-coupon xi such that xi=ƒ(ri), where ƒ is a predetermined one-way function, the method including the following steps: the verifier device sends a challenge consisting of a random value c to the prover device; the prover device sends to the verifier device a response y calculated by using the pseudo-random number ri, the challenge c, and a secret key s belonging to the prover device; and the verifier device checks the validity of the response y based on the challenge c, the reduced-coupon xi corresponding to the pseudo-random number ri, and a public key V corresponding to the secret key s, the reduced-coupon xi being received by the verifier device from a source external to the prover device.
Abstract:
A method of implementing a block cipher algorithm by a device storing a fixed initialization datum includes determining, before execution of a first iteration of the algorithm in the course of a session, a modified initialization datum by way of a determined function supplied as input with the fixed initialization datum and a state value specific to the session. The state value may be stored in the device. The modified initialization datum may be used to implement the first iteration of the algorithm.
Abstract:
A method of authenticating an entity by a verification entity, said entities sharing a pair of secret keys X and Y. According to the invention said secret keys X and Y are n×m (n, m>1) binary matrices, said method comprising steps repeated r times (r≧1) of: the entity (1) to be authenticated and the verification entity (2) exchanging binary vectors a and b of n bits respectively drawn at random by the verification entity (2) and the entity (1) to be authenticated and the entity (1) to be authenticated drawing at random a noise binary vector c of m bits, each of said m bits being equal to 1 with a probability η less than ½, and calculating and sending to the verification entity (2) a response vector z of m bits equal to z=aX⊕bY⊕c; the verification entity calculating the Hamming weight (220′) of an error vector e=z⊕aX⊕bY; and then accepting (240′) the authentication if the Hamming weights of the r error vectors e satisfy a relationship of comparison (230′) to a parameter (T, t) that is a function of the probability η. Application to cryptographic protocols for authenticating electronic chips of very low cost.