Patent ID: 8689014

Claim:
A data encryption device comprising: at least one processor coupled via a bus to a memory, the processor being programmed to control one or more of: a key generating application configured to generate key information for encrypting and decrypting data; a table generation application configured to generate table information including pre-conversion data input before conversion processing and post-conversion data output after conversion processing; a determination application configured to determine whether first data for invalidating data is input or second data is input; a conversion application configured to perform conversion processing by converting input data, wherein in a case where the first data for invalidating data is input, the first data is converted into the second data, and in a case where the second data is input, the second data is converted into the first data; and an encryption application configured to search whether encrypted data is contained in the pre-conversion data in the table information and, when encrypted data is not contained in the pre-conversion data in the table information, output the encrypted data to a storage unit, and, when encrypted data is contained in the pre-conversion data in the table information the conversion application converts the encrypted data and the encryption application outputs the converted data to the storage unit; wherein, the second data is data obtained by decrypting the first data by an encryption algorithm of the encryption application such that in a case where the first data for invalidating data is input in the conversion application, the first data is output to the storage unit even after the conversion by the conversion application and the encryption by the encryption application are performed, and wherein, in a case where third data different from the first data and the second data is input, the conversion application outputs the third data to the encryption application without converting the third data.