Patent application number | Description | Published |
20080247547 | Data transmitting apparatus and data receiving apparatus - A data communication apparatus which improves security against eavesdropping is provided for secret communication using Y-00 protocol. In a data transmitting apparatus | 10-09-2008 |
20090103721 | DATA TRANSMITTING APPARATUS, DATA RECEIVING APPARATUS AND DATA COMMUNICATION APPARATUS - Provided is a data communication apparatus which is highly concealable and significantly increases time necessary for an eavesdropper to analyze cipher text. A multi-level code generation section ( | 04-23-2009 |
20090175631 | Pulse signal demodulation device - In an optical transmission system in which a pulse signal is converted into an optical signal before transmission, a pulse signal demodulation device capable of correctly demodulating the pulse signal is provided. An optical-to-electrical conversion section ( | 07-09-2009 |
20090323852 | DATA RECEIVING APPARATUS - To provide a receiving apparatus which is capable of demodulating information data from a multi-level modulated signal, which is generated by using a Y-00 protocol, without using high-performance component parts. In the receiving apparatus, the soft decision section | 12-31-2009 |
20090323955 | DATA TRANSMITTING APPARATUS AND DATA RECEIVING APPARATUS - In secret communication using a Y-00 protocol, provided is a data communication apparatus which realizes reduction in a random number generation speed by using a plurality of random number generators, and which also ensures security. The data communication apparatus includes: a plurality of random number generation sections | 12-31-2009 |
20100158249 | DATA TRANSMITTING APPARATUS AND DATA RECEIVING APPARATUS - Provided is a data communication apparatus which significantly increases time necessary for an eavesdropper to analyze cipher text and which is superior in concealability based on astronomical computational complexity. A multi-level signal, which is generated by using data and key information, has a minor amplitude modulation, which is based on a random number signal generated on a transmission side, overlapped thereon, and is then transmitted. On a receiving side, instead of data decision, three types of decision, i.e., “1”, “0” and “decision impossible”, are performed on a random number signal by using two threshold values whose interval is significantly wider than a modulation amplitude based on random numbers. Information of a bit whose decision is performed successively is returned to the transmission side, and the bit is used commonly as a new key. Accordingly, in a single transmitting/receiving apparatus, cipher text transmission and key distribution can be realized simultaneously. | 06-24-2010 |
20100266124 | DATA COMMUNICATION APPARATUS - A data communication apparatus wherein the stealthiness has been enhanced by significantly increasing the time required for a wiretapper to decrypt an encrypted text. The data communication apparatus is constituted by connecting a data transmitting apparatus and a data receiving apparatus via a transmission path. The data transmitting apparatus receives a first predetermined initial value (key information) and information data, generates a multi-valued signal the level of which varies substantially like a random number, and converts the multi-valued signal to a modulated signal of a predetermined modulation format for transmission. The data receiving apparatus demodulates the modulated signal to output the multi-valued signal, and then reproduces the information data from the multi-valued signal and a second predetermined initial value (key information) that is received. | 10-21-2010 |
20100303234 | DATA COMMUNICATION APPARATUS - A data communication apparatus wherein the stealthiness has been enhanced by significantly increasing the time required for a wiretapper to decrypt an encrypted text. The data communication apparatus is constituted by connecting a data transmitting apparatus and a data receiving apparatus via a transmission path. The data transmitting apparatus receives a first predetermined initial value (key information) and information data, generates a multi-valued signal the level of which varies substantially like a random number, and converts the multi-valued signal to a modulated signal of a predetermined modulation format for transmission. The data receiving apparatus demodulates the modulated signal to output the multi-valued signal, and then reproduces the information data from the multi-valued signal and a second predetermined initial value (key information) that is received. | 12-02-2010 |
20120328304 | OPTICAL TRANSMISSION SYSTEM - An optical transmission system for optically transmitting information between apparatuses via an optical transmission path. The system includes: a sending unit that emits, to the optical transmission path, excitation light for detecting an inter-apparatus connection via the path; a responding unit that receives the excitation light from the path and emits detection light to the path using light energy of the excitation light; a response receiving unit that receives the detection light from the path and outputs a detection light current; a detecting unit that detects presence/absence of the inter-apparatus connection based on the detection light current; a light signal transmitting unit that emits, to the path, a light signal for optically transmitting the information based on the detection result by the detecting unit; and a light signal receiving unit that receives the light signal from the path. | 12-27-2012 |
20130251017 | PROXIMITY CONTACTLESS COMMUNICATION APPARATUS CAPABLE OF SELECTING APPROPRIATE ENCODING METHOD ACCORDING TO BANDWIDTH BETWEEN ANTENNAS - A comparator circuit compares a test pattern generated by a test pattern generator circuit, with a test pattern transmitted to a memory card and returned from the memory card. A control circuit determines a bandwidth corresponding to frequency components correctly transmitted between a host apparatus and the memory card, based on the returned test pattern, and selects an encoding method requiring a maximum available bandwidth. The control circuit generates a notification message indicating the selected encoding method, and encodes the notification message using the selected encoding method, and transmit the encoded notification message to the memory card. The control circuit establishes communication between the host apparatus and the memory card, when receiving a response message including an acknowledgement to the notification message, from the memory card. | 09-26-2013 |
20130251060 | MULTILEVEL AMPLITUDE MODULATION DEVICE, MULTILEVEL AMPLITUDE DEMODULATION DEVICE, TRANSMISSION SYSTEM INCLUDING THESE, MULTILEVEL AMPLITUDE MODULATION METHOD, AND MULTILEVEL AMPLITUDE DEMODULATION METHOD - A multilevel amplitude modulation device for generating, from digital data, a multilevel amplitude modulation signal having four or more signal levels and outputting the generated signal, including: an average level calculator that selects one of a plurality of preliminarily prepared different candidates for a code word building method such that average level of a symbol array, obtained by adding a symbol for a code word of digital data to be transmitted to one or more already outputted symbols included in a multilevel amplitude modulation signal already outputted, is most approximate to voltage center of the four or more signal levels, and outputs a selection signal indicating the selected method; a signal converter that forms a codeword of the digital data in accordance with the method indicated by the selection signal; and a multilevel modulator that generates a multilevel amplitude modulation signal using the codeword and outputs the generated signal. | 09-26-2013 |