APPARATUS AND METHOD FOR ORDER-REVEALING ENCRYPTION IN MULTI-CLIENT ENVIRONMENT WITHOUT TRUSTED AUTHORITY

摘要

An apparatus and method for sequence exposure encryption is disclosed. A method for encrypting sequence exposure according to an embodiment of the present invention includes: encrypting a first plaintext using a first user's secret key and encrypting a second plaintext using a second user's secret key Obtaining a second ciphertext; Providing identification information of the first user and identification information of the second user to a first client device used by the first user and a second client device used by the second user; Receiving a first comparison key element generated using the first user's identification information, the second user's identification information, and the first user's secret key from the first client device, and from the second client device Receiving a second comparison key element generated using the identification information of the first user, the identification information of the second user, and the secret key of the second user; And comparing the first ciphertext and the second ciphertext in an encrypted state using a comparison key including the first comparison key element and the second comparison key element, and based on the comparison result, the first plaintext and And determining the size between the second plain text.