On Using RSA/ECC Coprocessor for Ideal Lattice-Based Key Exchange

Polynomial multiplication is one of the most costly operations ideal lattice-based cryptosystems. In this work, we study its optimizations when operands has coefficients close to 0. We focus on structure since it at core Key Encapsulation Mechanisms submitted NIST call for post-quantum cryptography. particular, propose optimization operation embedded devices by using a RSA/ECC coprocessor that provides efficient and secure large-integer arithmetic. context, compare Kronecker Substitution, already studied in [], with two specific algorithms introduce: KSV, variant substitution, an adaptation schoolbook multiplication, denoted Shift&Add. All these rely transformation polynomial Then, thanks algorithms, existing coprocessors dedicated can be re-purposed order speed-up schemes. The efficiency depends component specifications cryptosystem parameters set. Thus, establish methodology determine which algorithm use, given component, only implementing basic operations. Moreover, three are assessed chip ensuring theoretical matches practical results.