Abstract: The present invention provides a password authentication system in which a high security level can be maintained using a password with small number of digits. According to the invention, an operation result with a large number of digits is generated by logically operating using a user password memorized in the user's brain and a unique code which is secretly stored on the terminal device and is set for each website. The authentication processing is performed by using the operation result as an authentication password. Therefore, the user simply remembers the password with a small number of digits in his brain, and the authentication processing is performed using the complex password with a large number of digits. Furthermore, a different authentication password is outputted for each website just using one user password. As the result of this, the problem of the users forgetting their password is solved and the security level of the password authentication can be significantly improved.

Abstract: The present invention realizes an electronic signature system with high security level in which abuse of a signature key by a system administrator is prevented. A user sets an authentication information conceived by the user himself to his/her own signature key stored in the tamper resistant device (5) via the terminal device (2). When digitally signing an electronic document, the user transmits his/her own encrypted authentication information to the tamper resistant device (5) through the terminal device (2) and asks for permission to use his/her signature key. The tamper resistant device (5) decodes the inputted authentication information, verifies the decoded authentication information, and allows the digital signing only if the correct authentication information is entered. As a result, the electronic signature system in which only a user having valid use authority for the signature key can digitally sign is built.

Abstract: The present invention realizes an electronic signature system with high security level in which abuse of a signature key by a system administrator is prevented. A user sets an authentication information conceived by the user himself to his/her own signature key stored in the tamper resistant device (5) via the terminal device (2). When digitally signing an electronic document, the user transmits his/her own encrypted authentication information to the tamper resistant device (5) through the terminal device (2) and asks for permission to use his/her signature key. The tamper resistant device (5) decodes the inputted authentication information, verifies the decoded authentication information, and allows the digital signing only if the correct authentication information is entered. As a result, the electronic signature system in which only a user having valid use authority for the signature key can digitally sign is built.

Abstract: A controller of an air-fuel-ratio sensor according to an embodiment includes a current supplying unit, a sweep processing unit, and an abnormality detecting unit. The current supplying unit supplies a current to the pump cell through a first terminal connected with the pump cell so as to control the pump cell. The sweep processing unit executes a sweeping process in which a predetermined voltage or a predetermined current is applied to the detection cell through a second terminal connected with the detection cell so as to change a voltage and a current of the detection cell. The abnormality detecting unit detects a short-circuited state between the first terminal and the second terminal on the basis of a fluctuation in a voltage or a current, generated by the sweeping process, of the first terminal.

Abstract: A controller of an air-fuel-ratio sensor includes a control unit, a voltage-abnormality detecting unit, and a short-circuit-abnormality detecting unit. The control unit controls a current and a voltage of a gas sensor element through a plurality of terminals connected with the gas sensor element. The voltage-abnormality detecting unit changes, when at least one of voltages of the plurality of terminals is out of a predetermined range, a voltage level of an output voltage. The short-circuit-abnormality detecting unit causes, when the voltage level of the output voltage changes from a first voltage into a second voltage, a control unit to perform for a predetermined time a protective operation that suppresses currents from the control unit to the plurality of terminals, and detects, when the voltage level of the output voltage is the second voltage after the protective operation is released, a short-circuit abnormality.

Abstract: There is provided an abnormality detecting circuit. A clamp unit is configured to clamp an output voltage which is output from another device, such that the upper limit of the output voltage becomes a first clamp voltage which is generated on the basis of a constant voltage generated from a power supply voltage, or a second clamp voltage which is generated on the basis of the power supply voltage and which varies depending on the power supply voltage. A short-to-power detection unit is configured to compare the output voltage clamped by the clamp unit, with a predetermined threshold value which is generated on the basis of the power supply voltage, thereby detecting occurrence of a short to power.

Abstract: A controller of an air-fuel-ratio sensor according to an embodiment includes a current supplying unit, a sweep processing unit, and an abnormality detecting unit. The current supplying unit supplies a current to the pump cell through a first terminal connected with the pump cell so as to control the pump cell. The sweep processing unit executes a sweeping process in which a predetermined voltage or a predetermined current is applied to the detection cell through a second terminal connected with the detection cell so as to change a voltage and a current of the detection cell. The abnormality detecting unit detects a short-circuited state between the first terminal and the second terminal on the basis of a fluctuation in a voltage or a current, generated by the sweeping process, of the first terminal.

Abstract: A controller of an air-fuel-ratio sensor includes a control unit, a voltage-abnormality detecting unit, and a short-circuit-abnormality detecting unit. The control unit controls a current and a voltage of a gas sensor element through a plurality of terminals connected with the gas sensor element. The voltage-abnormality detecting unit changes, when at least one of voltages of the plurality of terminals is out of a predetermined range, a voltage level of an output voltage. The short-circuit-abnormality detecting unit causes, when the voltage level of the output voltage changes from a first voltage into a second voltage, a control unit to perform for a predetermined time a protective operation that suppresses currents from the control unit to the plurality of terminals, and detects, when the voltage level of the output voltage is the second voltage after the protective operation is released, a short-circuit abnormality.

Abstract: There is provided an abnormality detecting circuit. A clamp unit is configured to clamp an output voltage which is output from another device, such that the upper limit of the output voltage becomes a first clamp voltage which is generated on the basis of a constant voltage generated from a power supply voltage, or a second clamp voltage which is generated on the basis of the power supply voltage and which varies depending on the power supply voltage. A short-to-power detection unit is configured to compare the output voltage clamped by the clamp unit, with a predetermined threshold value which is generated on the basis of the power supply voltage, thereby detecting occurrence of a short to power.

Abstract: A server certificate issuing system in which existence of a Web server for which a certificate is to be issued can be confirmed and security is further improved is realized, wherein the user authentication is carried out using a test certificate having the SSL certificate format. Servers transmit server certificate request to the registration server which transmits the test certificate request to the test certificate issuing authority. The test certificate issuing server transmits the generated test certificate to the registration server which transmits the test certificate to the corresponding server and requests to install the test certificate. Then, the registration server accesses with SSL protocol to the server and verifies whether or not the session of the SSL protocol has been established. The registration server transmits the CSR to the certificate issuing server only when the SSL protocol has been established.

Abstract: In a server certificate issuing system according to the invention, the Web server includes a control panel which configures and manages a Web and a mail. The control panel is loaded with an entry screen generator to input application items for an issuance of a server certificate, password generator for generating a password which is used to encrypt, and a verification page generator to indicate intention of requesting the issuance of the certificate. On the verification page, the generated password is indicated as verification information for example. The registration server retrieves the password from the received server certificate request and accesses the Web server to read out the verification information indicated on the verification page, and compares the read verification information with the password.

Abstract: An overcurrent protection apparatus includes two overcurrent protection circuits. The first overcurrent protection circuit compares an electric potential on the downstream side of a first resistance element with a reference potential produced by a second resistance element by a comparator and determines that overcurrent has been caused and intercepts current flowing through a first series regulator when the electric potential on the downstream side of the first resistance element is lower than the reference potential. When the resistance value of the second resistance element is larger than the resistance value of a fourth resistance element of the second overcurrent protection circuit, e.g., 1.2 times the resistance value of the fourth resistance element, the first overcurrent protection circuit intercepts the current flowing through the first series regulator at a current value of 1.2 times a current at which a downstream second series regulator is intercepted by the second overcurrent protection circuit.

Abstract: An input terminal is electrically connected to a contact point. An anti-corrosion current supplying section is operable to supply an anti-corrosion current to the contact point through the input terminal so as to remove corrosion in the contact point. A series resistor is electrically interposed between the input terminal of the signal processing circuit and the contact point. The anti-corrosion current is supplied to the contact point through the series resistor.

Abstract: A server certificate issuing system in which existence of a Web server for which a certificate is to be issued can be confirmed and security is further improved is realized, wherein the user authentication is carried out using a test certificate having the SSL certificate format. Servers transmit server certificate request to the registration server which transmits the test certificate request to the test certificate issuing authority. The test certificate issuing server transmits the generated test certificate to the registration server which transmits the test certificate to the corresponding server and requests to install the test certificate. Then, the registration server accesses with SSL protocol to the server and verifies whether or not the session of the SSL protocol has been established. The registration server transmits the CSR to the certificate issuing server only when the SSL protocol has been established.

Abstract: In a server certificate issuing system according to the invention, the Web server includes a control panel which configures and manages a Web and a mail. The control panel is loaded with an entry screen generator to input application items for an issuance of a server certificate, password generator for generating a password which is used to encrypt, and a verification page generator to indicate intention of requesting the issuance of the certificate. On the verification page, the generated password is indicated as verification information for example. The registration server retrieves the password from the received server certificate request and accesses the Web server to read out the verification information indicated on the verification page, and compares the read verification information with the password.

Abstract: A server certificate issuing system confirms existence of a Web server for which a certificate is to be issued. The web server includes means for generating an entry screen to input application matters for an issuance of a server certificate, means for generating a key pair a public key and a private key, means for generating a certificate signing request file (CSR) containing the generated public key, and means for generating a verification page indicating intention of requesting the issuance of the certificate. A registration server retrieves the CSR from a received server certificate request and accesses the Web server to read the verification information, and compares the read verification information with the CSR. If the verification information read from the Web server is identical to the CSR, it is determined that the Web server for which the server certificate is to be issued exists.

Abstract: An overcurrent protection apparatus includes two overcurrent protection circuits. The first overcurrent protection circuit compares an electric potential on the downstream side of a first resistance element with a reference potential produced by a second resistance element by a comparator and determines that overcurrent has been caused and intercepts current flowing through a first series regulator when the electric potential on the downstream side of the first resistance element is lower than the reference potential. When the resistance value of the second resistance element is larger than the resistance value of a fourth resistance element of the second overcurrent protection circuit, e.g., 1.2 times the resistance value of the fourth resistance element, the first overcurrent protection circuit intercepts the current flowing through the first series regulator at a current value of 1.2 times a current at which a downstream second series regulator is intercepted by the second overcurrent protection circuit.

Abstract: A circuit for preventing corrosion of a contact, includes an input terminal, a signal line, a switch, an impedance element, and a comparator. The input terminal is to be connected to the contact, which is outside the circuit. The signal line is connected to the input terminal. The switch is connected to the signal line. The impedance element is connected to the signal line in parallel to the switch. An impedance of the switching section is smaller than that of the impedance element. The comparator compares a potential of the signal line with a predetermined potential. The switch is turned on based on a comparison result output from the comparator.

Abstract: A server certificate issuing system confirms existence of a Web server for which a certificate is to be issued. The web server includes means for generating an entry screen to input application matters for an issuance of a server certificate, means for generating a key pair of a public key and a private key, means for generating a certificate signing request file (CSR) containing the generated public key, and means for generating a verification page indicating intention of requesting the issuance of the certificate. A registration server retrieves the CSR from a received server certificate request and accesses the Web server to read the verification information, and compares the read verification information with the CSR. If the verification information read from the Web server is identical to the CSR, it is determined that the Web server for which the server certificate is to be issued exists.

Abstract: A method for preventing corrosion of a contact, includes comparing a potential of a signal line connected to the contact with a predetermined potential corresponding to the corrosion of the contact; flowing a corrosion-prevention current into the contact when a result of the comparing shows that the contact is corroded; inputting into the signal line a signal used for judging a logical value of a connection state of the contact; and in the magnitude relation, setting the predetermined potential on another side of a threshold level used in the judging of the logical value of the connection state of the contact.