Described herein are systems and methods that prevent against fault injection attacks. In various embodiments this is accomplished by taking advantage of the fact that an attacker cannot utilize a result that has been faulted to recover a secret. By using infective computation, an error is propagated in a loop such that the faulted value will provide to the attacker no useful information or information from which useful information may be extracted. Faults from a fault attack will be so large that a relatively large number of bits will change. As a result, practically no secret information can be extracted by restoring bits.

There is provided a device of protecting an Integrated Circuit from perturbation attacks. The device includes a sensing unit configured to detect a perturbation attack, the sensing unit comprising a set of digital sensors comprising at least two sensors, the sensors being arranged in parallel. Each digital sensor provides a digitized bit output having a binary value, in response to input data, the sensing unit being configured to deliver at least one binary vector comprising a multi-bit value, the multi-bit value comprising at least two bit outputs provided by the set of digital sensors. The sensing device further comprising an analysis unit, the analysis unit being configured to receive at least one binary vector provided by the sensing unit, the analysis unit being configured to detect a perturbation attack from the at least one binary vector.

According to one aspect, a method for compiling by a compilation tool a source code into a computer-executable code comprises receiving the source code as input of the compilation tool, translating the source code into an object code comprising machine instructions executable by a processor, then introducing, between machine instructions of the object code, additional instructions selected from illegal instructions and no-operation instructions so as to obtain the executable code, then delivering the executable code as output of the compilation tool.

The disclosure concerns a method of protecting a calculation on a first number and a second number, including the steps of: generating a third number including at least the bits of the second number, the number of bits of the third number being an integer multiple of a fourth number; dividing the third number into blocks each having the size of the fourth number; successively, for each block of the third number: performing a first operation with a first operator on the contents of a first register and of a second register, and then on the obtained intermediate result and the first number, and placing the result in a third register; and for each bit of the current block, performing a second operation by submitting the content of the third register to a second operator with a function of the rank of the current bit of the third number, and then to the first operator with the content of the first or of the second register according to state 0 or 1 of said bit, and placing the result in the first or second register.

A calculation is performed on a first number and a second number. For each bit of the second number a first function is performed. The first function inputs include contents of a first register, contents of a second register and the first number. A result of the first function is placed in a third register. For each bit of the second number, a second function is performed which has as inputs contents of the third register and the contents of a selected one of the first and the second register according to a state of a current bit of the second number. A result of the second function is stored in the selected one of the first and second register.

In a method for determining the modular inverse of a number, successive iterations are applied to two pairs each including a first variable and a second variable, such that at the end of each iteration and for each pair, the product of the second variable and of the number is equal to the first variable modulo a given module. Each iteration includes at least one division by two of the first variable of a first pair or of a second pair, or a combination of the first variable of the first pair and of the first variable of the second pair by addition or subtraction. At least some of the iterations including a combination by addition or subtraction include a step of storing the result of the combination in the first variable of a pair determined randomly from among the first pair and the second pair. An associated cryptographic processing device is also described.

A system with fault injection attack detection can include a circuit block; at least one independent power network; a detector coupled to the at least one independent power network to detect a change in a power characteristic of the independent power network; and sensors coupled to the at least one independent power network and located in an active layer of a chip with the circuit block. The sensors are responsive to at least one type of fault injection attack. In some cases, the sensors can be inverters.

Various embodiments relate to a data processing system comprising instructions embodied in a non-transitory computer readable medium, the instructions for a cryptographic operation including matrix multiplication for lattice-based cryptography in a processor, the instructions, including: applying a first function to the rows of a matrix of polynomials to generate first outputs, wherein the first function excludes the identity function; adding an additional row to the matrix of polynomials to produce a modified matrix, wherein each element in the additional row is generated by a second function applied to a column of outputs associated with each element in the additional row; multiplying the modified matrix with a vector of polynomials to produce an output vector of polynomials; applying a verification function to the output vector that produces an indication of whether a fault occurred in the multiplication of the modified matrix with the vector of polynomials; and carrying out a cryptographic operation using output vector when the verification function indicates that no fault occurred in the multiplication of the modified matrix with the vector of polynomials.

Some embodiments are directed to a circuit compiling device for compiling a function into a binary circuit and a function evaluation device for evaluating a function using such a binary circuit. The binary circuit comprises conjunction subcircuits each computing a conjunction of function input bits and XOR subcircuits each computing a function output bit. Each function output bit may be represented as a sum of interpolation terms, the plurality of function input bits and the interpolation terms of the one or more function output bits together forming a plurality of interpolation terms. A conjunction subcircuit computes an interpolation term as a conjunction of two interpolation terms. A XOR subcircuit computes a function output bit as a XOR of interpolation terms. Thereby, the first interpolation term and second interpolation term are also used in XOR subcircuits, hence the binary circuit has a smaller number or likelihood of ineffective faults.

There is provided a device or a method for executing an operation of a cryptographic scheme, the operation being applied to a given state of a data block of original data, the operation being defined in a basis ring corresponding to the quotient of a starting ring by a basis ideal generated by at least one element of the starting ring. The operation is executed from a state derived from the current state of the data block, in at least one reference ring, which provides a reference value for each reference ring, each reference ring being the quotient of the starting ring by a reference ideal. The operation is executed from the state derived from the current state of the data block in at least one extended ring corresponding to one or more reference rings, which provides at least one extension value for each extended ring, each extended ring corresponding to one or more reference ring being the quotient of the starting ring by the product of the basis ideal and of the reference ideals of the one or more corresponding reference rings.