Abstract: A tag decides a response based on a plurality of queries received from a reader, determines whether to transmit the response, transmits the response to the reader according to the results of the determination, and transmits a message authentication code including communication content to the reader. The reader calculates a consumed time period which is the time difference between a transmission time at which the queries are transmitted and a reception time at which the response is received, calculates an average consumed time period of the consumed time period, and measures a distance to the tag based on the average consumed time period. Accordingly, it is possible to check an attacker's intervention with a high probability, thereby improving distance measurement performance. Also, the tag may efficiently perform computing and communication.

Abstract: A multi-user searchable encryption system includes a key generation center to issue a private secret key to a user and trace information regarding a user who has generated an index, and a user terminal device to generate an index for searching for a database using the private secret key. The multi-user searchable encryption system includes a database (DB) server that verifies the index generated by the user terminal device and searches for corresponding data to the verified index.

Abstract: Proposed is a data visualizing apparatus for visualizing data as effectual information using a correlation between forensic data collected from various sources. The proposed data visualizing apparatus may visualize, as effectual information, single-source single-data, single-source multi-data, and multi-source multi-data.

Abstract: An order-preserving encryption apparatus includes an initializer for setting a total space of a ciphertext with respect to a total space of a plaintext by considering security of the ciphertext, and setting a secret key for encryption and a pseudo-random number generator for generation of a pivot. Further, the order-preserving encryption apparatus includes a pivot generator for applying the secret key to the established pseudo-random number generator to generate a pivot for the plaintext to be encrypted. Further, the order-preserving encryption apparatus includes a ciphertext generator for generating information about size of a bit constituting the ciphertext by comparing the generated pivot and the plaintext; and a plaintext adjusting unit for adjusting a magnitude of the total plaintext space and a magnitude of the plaintext according to the ciphertext.

Abstract: Disclosed is a method for searchable symmetric encryption. The method for performing searchable encryption and searching for encrypted data includes: setting all necessary variables and preparing a secret key necessary for encryption; encrypting a data using the secret key and a given data and generating an index to be used for later search, to store the encrypted data and the index; generating a trapdoor to be used to search the encrypted data by using the secret key and a keyword to be used for the searching; and searching a desired data using the generated trapdoor and the stored index.

Abstract: Provided is a forensic index method by distributed processing, including: generating data to be divided by dividing data to be indexed according to predetermined division setting for distributed processing; allocating the generated data to be divided to a plurality of data processing units according to the predetermined division setting, extracting an index by filtering the allocated data to be divided in the plurality of data processing units, and generating divided index data including the extracted index; and generating an index database by merging the generated divided index data.

Abstract: There are provided an apparatus and a method for privacy protection in association rule mining among data mining technologies. An apparatus for privacy protection in association rule mining according to an embodiment of the present invention comprises: a fake transaction inserter that generates fake transactions of a predetermined number each having a predetermined length and inserts the fake transactions between a plurality of transactions comprised in an original data set to generate a first virtual data set; and a distortion transaction generator that generates a second virtual data set by converting data of the transaction of the first virtual data set with a predetermined probability.

Abstract: A method of user-authenticated quantum key distribution according to the present invention shares a position having the same basis without making public basis information using previously shared secret keys and authenticates a quantum channel by confirming whether there is the same measured outcome at that position, in order to secure unconditional security of BB84 quantum key distribution (QKD) protocols vulnerable to man-in-the-middle attack.

Abstract: A system and method for data analysis and digital forensics is provided. The system for data analysis and digital forensics may include: an online data forensic server for collecting and analyzing usage history information from an object device, which is subject to data collection, downloading and collecting data on the Internet based on the usage history information, requesting issuance of a timestamp token for the collected data, and receiving the issued timestamp token; a timestamp token issuing server for issuing the timestamp token for the collected data in response to the request for issuance of the timestamp token and proving the issued timestamp token to the online data forensic server; and a storage device for storing the collected data.

Abstract: Proposed is a data visualizing apparatus for visualizing data as effectual information using a correlation between forensic data collected from various sources. The proposed data visualizing apparatus may visualize, as effectual information, single-source single-data, single-source multi-data, and multi-source multi-data.

Abstract: Provided is a forensic index method by distributed processing, including: generating data to be divided by dividing data to be indexed according to predetermined division setting for distributed processing; allocating the generated data to be divided to a plurality of data processing units according to the predetermined division setting, extracting an index by filtering the allocated data to be divided in the plurality of data processing units, and generating divided index data including the extracted index; and generating an index database by merging the generated divided index data.

Abstract: A mobility technology for strengthening safety for an invasion of privacy caused by leakage of contact information is provided. A privacy protection system may include an acquisition attempt detecting unit to detect an external communication terminal that attempts to acquire contact information included in the profile, and an access controller to provide the detected external communication terminal with a right to use the contact information, and to determine whether the contact information is to be provided.

Abstract: Provided are methods of storing and searching for data in encrypted form. The method of storing data in encrypted form includes: encrypting desired data from among data stored in a database; dividing an entire region of the stored data into a plurality of bucket regions and allocating an index to each of the bucket regions; identifying order information in a bucket region to which the encrypted data belongs; and storing the encrypted data, index information of the bucket region to which the encrypted data belongs, and the identified order information in an external server. When a database containing important data of at least one user is stored in an external server using the above storing method, the security and efficiency of the database can be increased.

Abstract: An apparatus for creating a data table of a forensic data, includes a data parser configured to create primary data tables including unique attributes of the predetermined keywords by parsing the raw data having different formats for each forensics tool, each attribute having a unique standardized format. The apparatus further includes a data filter filtering specific fields or attributes from the primary data tables to newly create secondary data table. The apparatus further includes a data relation analyzer analyzing a relation between the data within the primary data tables to newly create secondary data tables.

Abstract: An order-preserving encryption apparatus includes an initializer for setting a total space of a ciphertext with respect to a total space of a plaintext by considering security of the ciphertext, and setting a secret key for encryption and a pseudo-random number generator for generation of a pivot. Further, the order-preserving encryption apparatus includes a pivot generator for applying the secret key to the established pseudo-random number generator to generate a pivot for the plaintext to be encrypted. Further, the order-preserving encryption apparatus includes a ciphertext generator for generating information about size of a bit constituting the ciphertext by comparing the generated pivot and the plaintext; and a plaintext adjusting unit for adjusting a magnitude of the total plaintext space and a magnitude of the plaintext according to the ciphertext.

Abstract: A lattice-based ring signature method includes generating a dimension, a bound, a length of a hashed message, a Gaussian parameter and an open parameter, which are parameters necessary for a ring signature. Further, the lattice-based ring signature method includes generating a signature key and a verifying key for a user who construct a ring by using the parameter necessary for the ring signature. Furthermore, the lattice-based ring signature method generating a signature for a message and the ring by using the signature key and the verifying key.

Abstract: A data management apparatus includes an index generation unit configured to subdivide an entire interval of data into bucket intervals, allocate indices for the respective bucket intervals, transform the bucket intervals having the allocated indices into bucket intervals of specific lengths, and generate bucket-based indices for pieces of data included in the bucket intervals of the specific lengths. The data management apparatus further includes a data management unit configured to transmit the encrypted data and the bucket-based indices to a server-side data management apparatus in order to store the encrypted data, transmit a user query to the server-side data management apparatus in order to search for a desired encrypted data, and decrypt encrypted data corresponding to the user query from the server-side data management apparatus. The user query includes the index of first bucket interval and the index of second bucket interval neighboring to the first bucket interval.

Abstract: A digital forensic apparatus for analyzing user activities includes: a collection unit for collecting analysis information related to user activities from a device as an investigation target for analyzing the user activities; and an analysis unit for analyzing the analysis information collected by the collection unit to determine activity information of a user from each type of the analysis information, and for causing the activity information to be arranged and displayed in temporal order.

Abstract: A system and method for data analysis and digital forensics is provided. The system for data analysis and digital forensics may include: an online data forensic server for collecting and analyzing usage history information from an object device, which is subject to data collection, downloading and collecting data on the Internet based on the usage history information, requesting issuance of a timestamp token for the collected data, and receiving the issued timestamp token; a timestamp token issuing server for issuing the timestamp token for the collected data in response to the request for issuance of the timestamp token and proving the issued timestamp token to the online data forensic server; and a storage device for storing the collected data.

Abstract: A ring authentication method for a concurrency environment, the method capable of providing unforgeability, sender anonymity, and deniability in the concurrency environment, in which, when a receiver receiving a message requests a sender of the message to certify the message, the sender requested to certify the message sends a message certification value certifying that the sender is one of a plurality of users {P1, . . . , Pn} and authenticates the message m to the receiver, and the receiver verifies the sent message certification value and authenticates that the message is sent from the one of the plurality of users {P1, . . . , Pn}.