Abstract: An apparatus and method for controlling a packet transfer period of key resynchronization information in an encryption communication system are provided. The encryption communication apparatus includes a receiving means that computes a packet loss ratio and a network transfer delay time through a received packet when the packet is received and generates network status report information for a packet size and a packet transfer period of key resynchronization information using the packet loss ratio and the network transfer delay time, and a transmitting means that transmits a packet of the key resynchronization information in the transfer period by controlling the packet size and the packet transfer period of the key resynchronization information according to the network status report information received from the receiving means when data is input.

Abstract: A random number generation apparatus and method using input time information is provided. The random number generation apparatus using input time information includes an information obtainment unit for obtaining input time information from input means. An initial value calculation unit calculates an initial value for random number generation using the input time information. A random number generation unit generates a random number using the initial value for random number generation.

Abstract: A device for protecting data stored in a static random access memory (SRAM) is provided. More particularly, a device for protecting SRAM data including an SRAM data erasing circuit, which erases memory stored in an SRAM at once when illegal separation from a system is detected. The device for protecting SRAM data includes: a power switching circuit for outputting electrical power supplied from an external power supply or a back-up battery power supply depending on whether the external power supply is supplying the electrical power or not; and an SRAM data erasing circuit for supplying the electrical power output from the power switching circuit to a power input terminal of a SRAM or grounding the power input terminal of the SRAM, in response to a connecter connection signal. The device can prevent illegal leakage of SRAM data by erasing the data stored in the SRAM when the SRAM is illegally separated from a system according to the switch setting of the SRAM data erasing circuit.

Abstract: A tamper detection method and a data storage device using the same are provided. The tamper detection method includes sensing a value of pressure applied to a data storage device using a pressure sensor, comparing the sensed pressure value with an initial pressure value sensed at an initial operation time of the data storage device, and detecting malicious tamper by comparing a threshold pressure value varying with the number of loads applied to the data storage device when the sensed pressure value is smaller than the initial pressure value.

Abstract: An apparatus and method for controlling a packet transfer period of key resynchronization information in an encryption communication system are provided. The encryption communication apparatus includes a receiving means that computes a packet loss ratio and a network transfer delay time through a received packet when the packet is received and generates network status report information for a packet size and a packet transfer period of key resynchronization information using the packet loss ratio and the network transfer delay time, and a transmitting means that transmits a packet of the key resynchronization information in the transfer period by controlling the packet size and the packet transfer period of the key resynchronization information according to the network status report information received from the receiving means when data is input.

Abstract: Provided are a system and method for distributing a group key for a video conference using a one-time password in a video conference system. The method includes: when a video terminal is required to participate in a video conference, generating a challenge value and a response value corresponding to the video terminal; encrypting a group key corresponding to the video conference with the response value, and transmitting the encrypted group key and the challenge value to the video terminal; and causing the video terminal to participate in the video conference in response to an acknowledgement message from the video terminal. This results in high user friendliness and high-level security.

Abstract: A device for protecting data stored in a static random access memory (SRAM) is provided. More particularly, a device for protecting SRAM data including an SRAM data erasing circuit, which erases memory stored in an SRAM at once when illegal separation from a system is detected. The device for protecting SRAM data includes: a power switching circuit for outputting electrical power supplied from an external power supply or a back-up battery power supply depending on whether the external power supply is supplying the electrical power or not; and an SRAM data erasing circuit for supplying the electrical power output from the power switching circuit to a power input terminal of a SRAM or grounding the power input terminal of the SRAM, in response to a connecter connection signal. The device can prevent illegal leakage of SRAM data by erasing the data stored in the SRAM when the SRAM is illegally separated from a system according to the switch setting of the SRAM data erasing circuit.

Abstract: Provided are an apparatus and method for synchronizing time information of both transmitting and receiving side using a key re-synchronization frame in encryption communications that require algorithm synchronization.

Abstract: Provided are an apparatus and method for estimating a voice data value corresponding to a silent period produced in a key resynchronization process using the sine waveform characteristic of voice when encrypted digital voice data is transmitted in one-way wireless communication environment. The apparatus includes a transmitter that generates a key resynchronization frame containing key resynchronization information and vector information on voice data inserted thereinto and transmits the key resynchronization frame, and a receiver that receives the key resynchronization frame from the transmitter, extracts the vector information inserted in the key resynchronization frame, and estimates a voice data value corresponding to the key resynchronization period. Based on change ratio between slopes calculated using received voice data, it is possible to estimate the voice data corresponding to a silent period, which improves communication quality.

Abstract: Disclosed are a method of inserting vector information for estimating voice data in a key re-synchronization period, a method of transmitting vector information, and a method of estimating voice data in a key re-synchronization period using vector information, capable of estimating the voice data that corresponds to a silent period occurring in a key re-synchronization process when an encrypted digital voice is transmitted in a unidirectional wireless communication environment. A transmitter side inserts accumulation information (i.e., vector information) of a voice change direction of the transmitted previous frame in a key re-synchronization frame, using a voice feature that draws a sine wave, when making the key re-synchronization frame for the re-synchronization, and transmits the key re-synchronization frame with the vector information inserted thereto. A receiver side estimates the voice data value in the key re-synchronization period using the accumulation information (i.e.

Abstract: An individual information protecting card is formed by multiple image frequency transformation of the invention is a system utilizing a simplicity of bar cade and an image property of hologram in complexity which is a frequency card being simple in construction. Data to be recorded to the protecting card utilizes an image-based system different from existing numeric cipher code-based system. The image to be used can use not only use a binary image for letters, but also can use continuous grey level as photograph. However, the difference is not in the frequency card exposed externally. Accordingly, expansion to image protecting form is possible and application to a system for managing an information by allocating special image information by individual and by article list is possible. Output of card construction system is made by a reading card possessed by a system operator, a resolution card for increasing of resolution, and user's card being a protecting card.