Abstract: Provided is a method for threshold secret sharing and reconstruction for multi-compartment, and more particularly, to a method for creating a share and reconstructing a secret in a system constituted by a plurality of compartments. The method for threshold secret sharing for multi-compartments may include: an operation of creating, when at least one second compartment is related toward a first compartment in one direction, an encrypted secret value by using an external share which does not belong to the first compartment, but belongs to the at least one second compartment; an operation of creating a first polynomial for defining the first compartment by using the encrypted secret value; and an operation of creating an internal share of the first compartment by using the first polynomial.

Abstract: Provided is a share hardening method for multi-factor threshold secret sharing which includes an arbitrary share predetermined by a user and is capable of guaranteeing a security. The share hardening method for multi-factor threshold secret sharing may include an operation of accepting at least one predetermined first share value, an operation of randomly generating at least one second share value corresponding to the at least one predetermined first share value, an operation of determining an aggregate share using the at least one predetermined first share value and the at least one second share value, an operation of generating a polynomial for threshold secret sharing based on the determined aggregate share, and an operation of generating the remaining full shares based on the generated polynomial.