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: 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 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: 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: 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 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}.

Abstract: A remote forensics system based on a network is provided to allow for accessing a forensics analysis center from a remote area to perform forensic analysis. The network-based remote forensic system includes: one or more remote terminals performing forensic analysis on an evidence device in a remote area, through a virtual forensic tool when the evidence device is connected thereto; and an investigation center system connected to the remote terminals via a wide area network to provide the virtual forensic tool, processing a requirement of the remote terminals, and providing requirement processing results to the remote terminals.

Abstract: An apparatus for collecting evidence data includes: an online data collection unit for collecting online data from a location designated by a user; a screen capture unit for capturing shots viewed on a computer screen, as they are; a time stamping unit for calculating a message digest for the collected online data to generate a time stamp including date and time when the message digest has been generated and a signature of the time stamping unit itself; and an image generation unit for generating a forensic image for the collected online data and generating a message digest for the collected online data.

Abstract: Provided are an apparatus and a method for deciphering a password. The password deciphering apparatus includes a host control unit and at least two graphic processing units. The host control unit generates candidate passwords for detection of a password of a ciphered document file, and allocates the generated candidate passwords to at least two graphic processing units in a non-overlapping manner. The graphic processing units output password detection information when detecting the password of the document file by searching the allocated candidate passwords. Herein, upon receiving the password detection information from one of the graphic processing units, the host control unit uses the password detection information to detect the password.

Abstract: Provided are a key establishment method and system using commutative linear functions. In the method, a server defines a set of linear functions that use elements of a first finite field as coefficients and satisfy a commutative rule, selects a first linear function from the set, and selects a predetermined element from a second finite field. Next, the server selects a second linear function corresponding to each of nodes from the set, generates a predetermined combination function based on the first and second linear functions, generates a value of the second linear function using the selected element as a factor, and transmits the combination function and the value of the second linear function to a corresponding node. Each node receives the value of the second linear function from a server, exchanges the received values with the other nodes, computes a value using the exchanged value as a factor of the combination function, and establishes the computed value as a shared key between the nodes.