Solinas primes of small weight for fixed sizes
We give a list of the Solinas prime numbers of the form $f(2^k)=2^m - 2^n \pm 1$, $m \leq 2000$, with small modular reduction weight $wt < 15$, and $k=8,16,32,64$, i.e., $k$ is a multiple of the computer integer arithmetic word size. These can be useful in the construction of cryptographic protocols.
On differences of quadratic residues
Factoring an integer is equivalent to express the integer as the difference of two squares. We test that for any odd modulus, in the corresponding ring of remainders, any element can be realized as the difference of two quadratic residues, and also that, for a fixed remainder value, the map assigning to each modulus the number of ways to express the remainder as difference of quadratic residues is non-decreasing with respect to the divisibility ordering in the odd numbers. The reduction to remainders rings of the problem to express a remainder as the difference of two quadratic residues does not diminish the complexity of the factorization problem.
Parallel Itoh-Tsujii Multiplicative Inversion Algorithm for a Special Class of Trinomials
In this contribution, we derive a novel parallel formulation of the standard Itoh-Tsujii algorithm for multiplicative inverse computation over GF($2^m$). The main building blocks used by our algorithm are: field multiplication, field squaring and field square root operators. It achieves its best performance when using a special class of irreducible trinomials, namely, $P(X) = X^m + X^k + 1$, with $m$ and $k$ odd numbers and when implemented in hardware platforms. Under these conditions, our experimental results show that our parallel version of the Itoh-Tsujii algorithm yields a speedup of about 30% when compared with the standard version of it. Implemented in a Virtex 3200E FPGA device, our design is able to compute multiplicative inversion over GF($2^193$) after 20 clock cycles in about $0.94\mu$S.
Counting Prime Numbers with Short Binary Signed Representation
Modular arithmetic with prime moduli has been crucial in present day cryptography. The primes of Mersenne, Solinas, Crandall and the so called IKE-MODP have been extensively used in efficient implementations. In this paper we study the density of primes with binary signed representation involving a small number of non-zero $\pm 1$-digits.
Low Complexity Bit-Parallel Square Root Computation over GF($2^m$) for all Trinomials
In this contribution we introduce a low-complexity bit-parallel algorithm for computing square roots over binary extension fields. Our proposed method can be applied for any type of irreducible polynomials. We derive explicit formulae for the space and time complexities associated to the square root operator when working with binary extension fields generated using irreducible trinomials. We show that for those finite fields, it is possible to compute the square root of an arbitrary field element with equal or better hardware efficiency than the one associated to the field squaring operation. Furthermore, a practical application of the square root operator in the domain of field exponentiation computation is presented. It is shown that by using as building blocks squarers, multipliers and square root blocks, a parallel version of the classical square-and-multiply exponentiation algorithm can be obtained. A hardware implementation of that parallel version may provide a speedup of up to 50\% percent when compared with the traditional version.