Patent ID: 8688985

Claim:
A data security method using a characteristic preserving encryption performed in a data security apparatus disposed separately from a user terminal and a database server, the data security method comprising: receiving by the data security apparatus a source data transferred from the user terminal; generating by the data security apparatus a reference data with a random data, wherein a length and a format of the reference data are the same as a length and a format of the source data, generating by the data security apparatus a mapping table in which the reference data and the source data are mapped, encrypting by the data security apparatus the mapping table to perform a characteristic preserving encryption for the source data; storing by the data security apparatus the encrypted mapping table in the data security apparatus; saving a use authority information having at least one of generator information and reader information, wherein the use authority information is information on a use authority for using an encrypted data, the generator information is information on a user requesting the encryption, and the reader information is information on a user being allowed to read the source data; transmitting by the data security apparatus the reference data to the user terminal so that the user terminal transmits the reference data to the database server, or directly to the database server so that the database server saves the reference data in the database server; and storing by the database server the reference data in the database server.