Abstract: Some embodiments are directed to a server device (100) and a client device (200) arranged to authenticating a user of client device (200). The user has access to an authentication string. Server device (100) is configured to encrypt a set of character/position data according to a homomorphic encryption algorithm. The client device allows the user to select a subset from the encrypted set from which a verification number is computed using the homomorphic operation.

Abstract: A cryptographic device (100) arranged to compute a target block cipher (Bt) on an input message (110), the device comprising a first and second block cipher unit (121, 122) arranged to compute the target block cipher (Bt) on the input message, and a first control unit (130) arranged to take the first block cipher result and the second block cipher result as input, and to produces the first block cipher result only if the block cipher results are equal.

Abstract: Some embodiments are directed to a keyed message authentication code (MAC) device (100) for computing a keyed MAC for an input message using encoded representations. The keyed MAC device may be configured to apply a sequence of compressions functions, at least one of which takes a state as input in an encoded representation.

Abstract: A cryptographic device is configured to compute a target block cipher (Bt) on an input message and includes a control unit, and first and second block cipher units for computing the target block cipher (Bt) on the input message. The control unit is configured to take the first block cipher result and the second block cipher result as input, and to produce the first block cipher result only when the first and second block cipher results are equal.

Abstract: Some embodiments are directed to a cryptographic device (100) arranged to compute a block cipher on an input message (110). The device computes a plurality of intermediate block cipher results by computing and re-computing a first intermediate block cipher result (151) of the plurality of intermediate block cipher results by applying the plurality of block cipher rounds sequentially to the input message followed by one or more additional block cipher rounds. A plurality of averaging functions are applied to the plurality of intermediate block cipher results, the results of which are added, after which the inverse of the one or more additional block cipher rounds is applied.

Abstract: A computation device (200) arranged to evaluate a data function (S) mapping a number (n) of input variables to a number of output variables (m). The computation device comprises selection mechanism (220) receiving as input selection variables and an evaluation mechanism (210) arranged to receive the one or more evaluation variables and to evaluate the evaluation functions for the received evaluation variables, an evaluation function receiving as input the evaluation variables.

Abstract: Some embodiments are directed to an electronic computation device (100) arranged for obfuscated execution of a multiplication. The device comprises a storage (120) arranged for storing multiple variables used in the execution of an arithmetic operation, a variable (x: y; 2) of the multiple variables being represented as multiple multiplicative shares (X=(x0, x1, . . . , xm?1); Y=(y0, y1, . . . , ym?1); 20), said multiplicative shares being represented in the storage as multiple additive shares (xi=(xi,0,xi,1, . . . , xi,n?1); Yi=(yi,0,yi,1, . . . , yi,n?1); 210, 220).

Abstract: Some embodiments are directed to an electronic cryptographic device arranged to perform a cryptographic operation on input data obtaining output data. The cryptographic device stores an internal state as sets of shares. Fourier coefficients corresponding to the sets of shares satisfy a predetermined relationship among them. The cryptographic operation is performed by repeatedly updating the internal state.

Abstract: An electronic calculating device (100; 200) arranged to calculate the product of integers, the device comprising a storage (110) configured to store integers (210, 220) in a multi-layer residue number system (RNS) representation, the multi-layer RNS representation having at least an upper layer RNS and a lower layer RNS, the upper layer RNS being a residue number system for a sequence of multiple upper moduli (Mi), the lower layer RNS being a residue number system for a sequence of multiple lower moduli (mi), an integer (x) being represented in the storage by a sequence of multiple upper residues (xi=(x)Mi; 211, 221) modulo the sequence of upper moduli (Mi), upper residues (xj; 210.2, 220.

Abstract: Some embodiments are directed to a cryptographic device (100) arranged to compute a block cipher on an input message (110). The device computes a plurality of intermediate block cipher results by computing and re-computing a first intermediate block cipher result (151) of the plurality of intermediate block cipher results by applying the plurality of block cipher rounds sequentially to the input message followed by one or more additional block cipher rounds. A plurality of averaging functions are applied to the plurality of intermediate block cipher results, the results of which are added, after which the inverse of the one or more additional block cipher rounds is applied.

Abstract: A cryptographic device (200) is provided to compute a key dependent cryptographic function for an input message. The cryptographic device has a data store arranged to store multiple variables (w) on which the cryptographic device acts to compute the cryptographic function, a variable (w) being distributed over multiple shares (wj) and represented in the data store as multiple encoded shares (xj), an encoded share being an encoding (xj=Encj (wj, sj)) of a share (wj) together with a state (sj), the multiple states (sj) corresponding to the same variable (w) having a relationship with the input message (M) so that there exists an injective mapping (?) from the input message (M) to the multiple states (?(M)=(s0, . . . , sn?1)).

Abstract: An electronic calculating device (100) arranged to convert an input number (y) represented ((y1, y2, . . . , yk)) m a residue number system (RNS) to an output number represented in a radix representation ((e0, e1, . . . es?1)), the calculating device comprising an input interface (110) arranged to receive the input number (y) represented in the residue number system, and a processor circuit (120) configured to iteratively update an intermediate number (?) represented in the residue number system, wherein iterations produce the digits (e0, e1, . . . es?1) in the radix representation with respect to the bases (b0, b1, . . . , bs?1), at least one iteration comprises computing the intermediate number modulo a base (bt) of the radix representation to obtain a digit (et=(?)bt) of the radix representation, updating the intermediate number (??(??et+F)/bt) by subtracting the digit from the intermediate number, adding an obfuscating number (F; Ft), and dividing by the base (bt).

Abstract: A cryptographic device (200) is provided to compute a key dependent cryptographic function for an input message. The cryptographic device has a data store arranged to store multiple variables (w) on which the cryptographic device acts to compute the cryptographic function, a variable (w) being distributed over multiple shares (wj) and represented in the data store as multiple encoded shares (xj), an encoded share being an encoding (xj=Encj (wj, sj)) of a share (wj) together with a state (sj), the multiple states (sj) corresponding to the same variable (w) having a relationship with the input message (M) so that there exists an injective mapping (?) from the input message (M) to the multiple states (?(M)=(s0, . . . , sn?1)).

Abstract: A cryptographic device (100) arranged to compute a target block cipher (Bt) on an input message (110), the device comprising a first and second block cipher unit (121, 122) arranged to compute the target block cipher (Bt) on the input message, and a first control unit (130) arranged to take the first block cipher result and the second block cipher result as input, and to produces the first block cipher result only if the block cipher results are equal.