Abstract: Various embodiments relate to a method for masked decoding of a polynomial a using an arithmetic sharing a to perform a cryptographic operation in a data processing system using a modulus q, the method for use in a processor of the data processing system, including: subtracting an offset ? from each coefficient of the polynomial a; applying an arithmetic to Boolean (A2B) function on the arithmetic shares of each coefficient ai of the polynomial a to produce Boolean shares âi that encode the same secret value ai; and performing in parallel for all coefficients a shared binary search to determine which of coefficients ai are greater than a threshold t to produce a Boolean sharing value {circumflex over (b)} of the bitstring b where each bit of b decodes a coefficient of the polynomial a.

Abstract: Various embodiments relate to a method for securely comparing a first polynomial represented by a plurality of arithmetic shares and a second compressed polynomial represented by a bitstring where the bits in the bitstring correspond to coefficients of the second polynomial, including: performing a first masked shift of the shares of the coefficients of the first polynomial based upon the start of the interval corresponding to the compressed coefficient of the second polynomial and a modulus value; performing a second masked shift of the shares of the coefficients of the first polynomial based upon the end of the interval corresponding to the compressed coefficient of the second polynomial; bitslicing the most significant bit of the first masked shift of the shares coefficients of the first polynomial; bitslicing the most significant bit of the second masked shift of the shares coefficients of the first polynomial; and combining the first bitsliced bits and the second bitsliced bits using an AND function to p

Abstract: Various embodiments relate to a method for securely comparing a first polynomial represented by a plurality of arithmetic shares and a second compressed polynomial represented by a bitstring where the bits in the bitstring correspond to coefficients of the second polynomial, including: performing a first masked shift of the shares of the coefficients of the first polynomial based upon the start of the interval corresponding to the compressed coefficient of the second polynomial and a modulus value; performing a second masked shift of the shares of the coefficients of the first polynomial based upon the end of the interval corresponding to the compressed coefficient of the second polynomial; bitslicing the most significant bit of the first masked shift of the shares coefficients of the first polynomial; bitslicing the most significant bit of the second masked shift of the shares coefficients of the first polynomial; and combining the first bitsliced bits and the second bitsliced bits using an AND function to p

Abstract: Various embodiments relate to a method for masked decoding of a polynomial a using an arithmetic sharing a to perform a cryptographic operation in a data processing system using a modulus q, the method for use in a processor of the data processing system, including: subtracting an offset ? from each coefficient of the polynomial a; applying an arithmetic to Boolean (A2B) function on the arithmetic shares of each coefficient ai of the polynomial a to produce Boolean shares âi that encode the same secret value ai; and performing in parallel for all coefficients a shared binary search to determine which of coefficients ai are greater than a threshold t to produce a Boolean sharing value {circumflex over (b)} of the bitstring b where each bit of b decodes a coefficient of the polynomial a.