Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Nippon Telegraph and Telephone Corporation

Matsushita Electric Co., Ltd.

Masaru Fuse

Satoshi Furusawa

Tsuyoshi Ikushima

Tomokazu Sada

Toru Shiozaki

Kuniaki Utsumi

Hiroyuki Sasai

Tomoaki Ohira

Jun Ohya

Katsuyuki Fujito

Seiichiro Kawashima

Toshihiko Yasue

Susumu Morikura

Kouichi Masuda

Hiroaki Nakata

Koji Kikushima

Hiroaki Yamamoto

Yosuke Matsushita

Hiroshi Yokota

Keisuke Kinoshita

Katsumi Iwatsuki

Mitsuhiro Teshima

Tsutomu Tanaka

Shigeru Kuwano

Yoshikazu Ishii

Kazuki Maeda

Tsutomu Niiho

Hiroaki Asano

Satoru Takagishi

Osamu Hirota

Masaki Souma

Fumio Fujisaki

Kuniharu Itakura

Hitoshi Uematsu

A terminal device includes a connection environment check unit, a determination purpose port mapping command unit which issues a port mapping command to a lower layer NAT device, and a determination packet generation unit which generates a determination packet which is source-routed. Additionally, a determination packet transmitting unit transmits the determination packet, a determination packet receiving unit receives the determination packet transmitted from the determination packet transmitting unit, passing through the upper layer NAT device a and the lower layer NAT device a and arriving at the terminal device a, and a port number obtainment unit obtains a WAN-side port number of the lower layer NAT device a indicated in the received determination packet.

Communication device, communication method, integrated circuit, and program

A data communication apparatus is highly concealable and significantly increases time necessary for an eavesdropper to analyze cipher text. A multi-level code generation section generates, by using predetermined key information, a multi-level code sequence in which a signal level changes so as to be random numbers. The multi-level processing section combines a multi-level code sequence and information data, and generates a multi-level signal having a level corresponding to a combination of the multi-level code sequence and the information data. In the multi-level code generation section, a random number sequence generation section generates a binary random number sequence by using the predetermined key information. A multi-level conversion section generates a multi-level code sequence from the binary random number sequence in accordance with a predetermined encoding rule.

Data transmitting apparatus, data receiving apparatus and data communication apparatus

A data communication apparatus wherein stealthiness is 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 in a random number manner, 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 received second predetermined initial value (key information).

Data communication apparatus

A data communication apparatus, performing a secret communication, is provided to reduce a random number generation speed using a plurality of random number generators. The data communication apparatus includes random number generation sections generating random numbers, which are each a multi-level pseudo random number, using predetermined key information includes a multi-level signal modulation section selecting a level, from among multi-levels previously prepared, selected level corresponding to information data and a multi-level sequence, which is composed of a combination of values of the random numbers and generating a multi-level modulated signal including a noise having a predetermined noise level using the selected level. Levels of a multi-level signal are in a range of the noise level, and a signal point allocation is set such that all values which are possibly taken by each of the random numbers are allocated to the plurality of levels of the multi-level signal.

Data transmitting apparatus and data receiving apparatus

An optical transmitting circuit () modulates multimode oscillation light using an information signal, subjects at least one oscillation-mode light beam of the multimode oscillation light to a predetermined operation, and outputting the result to an optical transmission channel. An optical receiving circuit () receives an optical signal transmitted through the optical transmission channel, subjects the received optical signal to an operation reverse to the predetermined operation to recover an optical signal as it was before being subjected to the predetermined operation, and converting the recovered optical signal into an electrical signal, thereby reproducing the information signal.

Multimode optical transmission device

A data transmitting apparatus has improved security against eavesdropping for secret communication using Y-00 protocol. The multi-level code generation section generates, based on key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers. The multi-level processing section generates a multi-level signal having a level which corresponds to a combination between information data and the multi-level code sequence. The error signal generation section generates an error signal which changes randomly. The accumulation section accumulates the error signal, and outputs an accumulated error signal. The adding section adds the accumulated error signal to the multi-level signal, and outputs a variable multi-level signal. The modulator section modulates the variable multi-level signal, and outputs a modulated signal.

Data transmitting 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 sectionperforms soft decision on the multi-level signal, in which a fixed decision level is used. A converted data identification sectionperforms logical decision on a value of the converted information datain accordance with a highest-order bit of a multi-level code sequenceand a decision resultof the soft decision. A data reproduction sectionperforms an XOR operation between the converted information dataand a lowest-order bit of the multi-level code sequence, and outputs a resultant thereof as information data. Accordingly, the receiving apparatus identifies the information databy using only some of the bits of the multi-level code sequence, whereby precision requirements for the component parts to be used can be eased.

Data receiving apparatus

A data transmitting apparatus generates, by using predetermined first key information and information data, a multi-level signal in which a signal level changes so as to be approximately random numbers, and converts the multi-level signal into a modulated signal, in a predetermined modulation method and transfer the same. A data receiving apparatus demodulates the modulated signal so as to be converted into a multi-level signal, and reproduces information data from the multi-level signal, using second key information which has the same content as first key information used by the data transmitting apparatus.

Data transmission apparatus, data receiving apparatus and method executed thereof

A data communication system that enhances concealment by significantly increasing the time required for a wiretapper to decrypt a cipher text. The data communication system is constituted by connecting a data transmitting apparatus () to a data receiving apparatus () via a transmission path (). In the data transmitting apparatus (), a multilevel encoding part () receives a predetermined first initial value (key information) and information data and generates a multilevel signal that varies in level substantially in a random number manner. A dummy signal superimposing part () superimposes a dummy signal on the multilevel signal. A modulating part () converts the multilevel signal to a modulated signal of a predetermined modulation form and transmits the modulated signal. The data receiving apparatus () demodulates the modulated signal to output the multilevel signal, and receives a predetermined second initial value (key information) and the multilevel signal to reproduce the information data.

Data communication system

A data communication apparatus which improves security against eavesdropping is provided for secret communication using Y-00 protocol. In a data transmitting apparatus, a multi-level code generation sectiongenerates, based on key information, a multi-level code sequencein which a signal level changes so as to be approximately random numbers. A multi-level processing sectiongenerates a multi-level signalhaving a plurality of levels each corresponding to a combination between information dataand the multi-level code sequence. A level conversion sectiondivides the plurality of levels of the multi-level signalinto several groups, and allocates one level of a converted multi-level signalto a plurality of levels included in each of the several groups in an overlapped manner. The level conversion sectionthen converts the multi-level signalinto the converted multi-level signal. A modulator sectionmodulates the converted multi-level signaland outputs a modulated signal

A dynamic range of intensity modulation is set to range from a maximum intensity Smax to a minimum intensity Smin. A difference &#x394;(=Smax&#x2212;Smin) between the maximum intensity Smax and the minimum intensity Smin is divided by the number 2M of multilevel signals. Thus, a distance (an intensity difference) between adjacent signals is [&#x394;/2M]. The number 2M of multilevel signals is selected such that the distance [&#x394;/2M] between adjacent multilevel signals (between an intensity Sand an intensity S) is sufficiently buried within a range of quantum fluctuations obtained when heterodyne measurements are made or buried within a range of quantum shot noise obtained when a direct detection is made. Bases of a basis group are each positioned for intensity signals so as to have a high intensity and a low intensity between which a distance is set to be a certain value smaller than a middle point intensity [&#x394;/2]. Note that adjacent bases are set to have an intensity signal transmitting a logical value '1' of transmission data and an intensity signal transmitting a logical value '0' of transmission data in an inverted manner.

Optical transmitter and transmitting method for transmitting cryptogram

A data communication apparatus improves security against eavesdropping for secret communication by using Y-00 protocol. A multi-level code generation section generates, based on key information, a multi-level code sequence in which a signal level changes so as to be approximately random numbers. A level conversion section irreversibly converts the multi-level code sequence such that a converted multi-level code sequence does not constitute a mapping of the multi-level code sequence. A multi-level processing section generates a multi-level signal having a plurality of levels each corresponding to a combination between the information data and the multi-level code sequence. A modulator section modulates a multi-level signal in a predetermined modulation method and outputs a modulated signal.

Data communication apparatus and data communication method

A highly concealable data communication apparatus based on an astronomical complexity and causing an eavesdropper to take a significantly increased time to analyze a cipher text, is provided. In a multi-level code generation section, a random number sequence generation sectiongenerates, based on predetermined key informationa plurality of modulation pseudo-random number sequences. The plurality of modulation pseudo-random number sequences is inputted to a multi-level conversion sectionas a part of an input bit sequence which is converted into a multi-level code sequenceA multi-level processing sectioncombines the multi-level code sequenceand information dataand generates a multi-level signalhaving a plurality of levels corresponding to a combination of the multi-level code sequenceand the information data

Encrypting of communications using a transmitting/receiving apparatus via key information based on a multi-level code signal and a pseudo-random number sequence for modulation with an information signal

A data communication apparatus which causes the eavesdropper to take a significantly increased time to analyze a cipher text and provides high concealability is provided. A multi-level code generation sectiongenerates, based on predetermined key information, a multi-level code sequencein which a signal level changes so as to be approximately random numbers. A multi-level processing sectioncombines the multi-level code sequenceand information data, and generates a multi-level signalhaving a plurality of levels corresponding to the combination of the multi-level code sequenceand the information data. A modulator sectiontreats the multi-level signal a predetermined modulating processing and generates a modulated signal. The multi-level code generation sectiongenerates the multi-level code sequencein accordance with a changed random number sequence which results from changing a bit series of a binary random number sequence generated based on the predetermined key information.

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Osaka, Japan

Masaru Fuse