METHOD OF ENCRYPTING DATA USING HOMOMORPHIC ENCRYPTION AND COMPUTING DEVICE PERFORMING THE METHOD

摘要

The present invention relates to a method to perform encryption using a homomorphic encryption algorithm in a computing device comprising: (A) a step of generating at least one ciphertext (Esk′(m_i)) by respectively encrypting at least one normal text (m_i, where 1<=i<=n, i and n are integer) using a symmetric key (sk′); (B) a step of generating an encrypted symmetric key (ck)(where, ck=Epk(sk′)) by encrypting the symmetric key (sk′) using a public key (pk) received by the computing device from an external device; and (C) a step of performing key switching each of the at least one ciphertext (Esk′(m_i)) to a ciphertext (Epk(m_i)) encrypted using the public key (pk) by a fully homomorphic or a semi homomorphic algorithm.