Abstract: A proactive threshold secret sharing cryptosystem using a set of servers. The cryptosystem is a threshold cryptosystem, in the sense that service is maintained if at least (k+1) out of n servers are active and honest. The secret signature key is compromised only if the adversary breaks into at least (k+1) servers. It is robust in the sense that the honest servers detect faulty ones and the service is not disrupted. It is recoverable, because if the adversary erases all the local information on the server it compromised, the information can be restored as soon as the server comes back to performing the correct protocol. The method and system has proactiveness, which means that in order to learn the secret, the adversary has to break into (k+1) servers during the same round of the algorithm because the shares of the secret are periodically redistributed and rerandomized. The present invention uses a verifiable secret sharing mechanism to get the security requirements during the update between two rounds.

Abstract: The invention relates to a process for generating digital signatures from portable apparatuses (A1, A2, . . . Ai . . . An) of the microprocessor-based card type, including means for computation, communication and retention of data, which means comprise at least one electrically programmable non-volatile memory, consisting in preparing enciphered data constituting coupons and loading these coupons into the non-volatile memories so as later to use these coupons in order to sign a message sent by a verifier device. According to the process, the preparation of the coupons is carried out by a certified central authority B or by the card itself.

Abstract: The present invention concerns a method of controlling the mode of access to wanted signals, such as picture signals (IMAGE), whereby the user selects an access mode to a wanted signal remotely. A first access mode consists in supplying the user with the original wanted signal (IMAGE), and second access mode consists in transmitting to the user alternately and periodically the wanted signal and a jamming signal (MIRE, IT) into a jammed signal. This jammed signal remains intelligible so that the user can determine the content of the wanted signal and, if necessary, select the first access mode. The two access modes are billed differently. Hardware implementations of the method are described for switching grids of switching nodes in a centralized architecture, and for digital distribution networks with a more futuristic distributed type architecture.

Abstract: In a light-wave distance meter based on light pulses, a light pulse radiation device radiates light pulses emitted by a light source device to a target of measurement, a light reception device receives reflected light pulses from the target, a sampling device samples reception signals, a timing device applies a dither of a certain range to the light pulse emission timing and sampling timing, a cumulative memory device stores sampled signals at a certain interval cumulatively, and a computation device calculates the distance to the target. The distance meter is capable of measuring the position of received light pulses at a resolution higher than the sampling timing.

Abstract: An improved method of storing or retrieving electronic records. An image identification code and time data provided by a trusted source, as well as a password, are combined to generate a key. The image identification code and time data are stored in a public directory associated with the image data stream. Further, attributes of the image stream, such as its size and a hash of at least a segment of the image data, are determined. The attributes are then used to generated a verification code. The verification code is placed in a private area associated with the data image stream, and the private area is encrypted with the previously generated key.

Abstract: A system for determining the shape and dimensions of a surface of an object includes a projector for projecting onto the object a spatially coded pattern of radiation, e.g., light. The system also includes a receiving device capable of imaging the reflected pattern, and a discriminator for determining which portion of the reflected pattern corresponds to which portion of the projected pattern. By this means, a received signal representing less than the complete reflection from the projected pattern can be correlated with a discrete portion of the scanned object. The procedure is repeated to obtain enough reliable data to generate a reasonably reliable surface profile. The resulting set of received signals and correlations are used to calculate the shape and dimensions of the object.

Abstract: A multi-component system for linking a user to a product or service provider includes a user processing device, a storage device, and a provider device. The storage device stores provider-specific application software, user-specific data, and a file management program. The storage device and the processing device are coupled to each other to form a user device which communicates with the provider device. Under direction of the file management program, the processing device carries out a recognition methodology which determines whether the processing device and the storage device are authorized to operate with each other. This aspect of the system makes it possible to render the storage device operable only with a specific user processing device, referred to as the principal processing device. This, in turn, reduces the possibility of fraud since the storage device cannot be used without the principal processing device.

Abstract: A probe which directs a light beam through a vapor plume in a first direction at a first angle ranging from greater than 0.degree. to less than 90.degree., reflecting the light beam back through the vapor plume at a 90.degree. angle, and then reflecting the light beam through the vapor plume a third time at a second angle equal to the first angle, using a series of mirrors to deflect the light beam while protecting the mirrors from the vapor plume with shields. The velocity, density, temperature and flow direction of the vapor plume may be determined by a comparison of the energy from a reference portion of the beam with the energy of the beam after it has passed through the vapor plume.

Abstract: The method for preventing monitoring of postage indicia data which is sent from a postage metering vault to a remotely located digital printer over a communication link between the meter vault and the digital printer. The meter is provided with an encryption engine for encrypting postage indicia data utilizing a encryption key. The digital printer includes a decryption engine for decrypting postage data received from said meter utilizing the same encryption key and then prints a postage indicia pursuant to the decrypted postage indicia data. The postage meter also includes a key manager for generating new encryption key pursuant to a token which is either randomly generated or generated pursuant to an algorithm by a similar encryption key manager located in the digital printer which token is also used to generate the decryption key for the decryption engine. As a result, the encryption keys are the same.

Abstract: A data communications system is described in which messages are processed using public key cryptography with a private key unique to one or more users (150) under the control of a portable security device (120), such as a smart card, held by each user, the system comprising: a server (130) for performing public key processing using the private key. The server (130) stores, or has access to, the private key for the, or each, user in encrypted form only. The private key is encrypted with a key encrypting key and each security device (120) comprises means for storing or generating the key encrypting key and providing the key encrypting key to the server (130). The server comprises secure means (360) to retrieve the encrypted private key for the user, decrypt the private key using the key encrypting key, perform the public key processing using the decrypted private key, and delete the decrypted private key after use.

Abstract: A system and method for establishing secured communications pathways across an open unsecured network, without compromising the security of any parties to the communication, involves establishing secured gateways or firewalls between the Internet and any party which desires protection by 1.) using a smart card to distribute shared secret keys between a computer which serves as the above-mentioned firewall and a client node on the Internet; 2.) using the shared private keys to establish mutual authentication between the gateway and the smartcard; 3.) generating a session or temporary secret key for use in further communications between the gateway and the client node once communications have been established; and 4.) encrypting further communications using the session key.

Abstract: A floppy disk, having a microprocessor and battery power supply, a magnetic field sensor, and an on switch on the central hub. A plurality of magnetic fields are placed on the disk housing, in a circular pattern around the disk's axis of rotation, and are detected using a magnetic field sensor located on the hub. When the floppy disk is placed into the computer's drive bay, the computer disk drive motor does an initial series of operating and idle time increments. The floppy disk magnetic field sensor detects the number of revolutions of the disk, and stores the revolutions per time increment. The computer then communicates with the floppy disk, using disk motor operation and idle times. The floppy disk communicates information to the computer, via the user who reads information on a LCD readout, located on the floppy disk, and types in the information on the computer keyboard. The floppy disk is used as a personalized key, for both installing and updating programs for continued use.

Abstract: A super password is a one time use password that is issued to a user for the singular purpose of reinitializing the user password system for a meter. When the meter is manufactured, the meter and the Data Center share secret data such that they can execute a predefined and identical algorithm for secure communication. Through such secure communications, the Data Center can authenticate a metering system, and the metering system can accept a predefined command from the Data Center securely. Counters are used as data to encrypt. One counter is used for the one way communication from the meter to the data center and counts the number of times that the meter issues a one time authentication code. Another counter is used for the one way communication from the Data Center to the meter and counts the number of times that the Data Center issues a one time super password. The counters are used for two purposes: as data to be encrypted and to confirm the delivery of secure codes between the Data Center and the meter.

Abstract: A digital conditional access module for a subscriber terminal comprises a decryption device including at least one PID register and an associated countdown register. The decryption device is enabled for decrypting received product packets having a PID matching a PID stored in the PID register so long as the associated countdown register is characterized by a non-zero value. Decryption of a product packet results in the countdown register being decremented by a selected factor, the countdown register being prevented from assuming a zero value by setting its contents to a selected value in response to a received conditional access packet containing a PID matching the PID stored in the PID register. The selected value to which the countdown register is set may also be contained within the received conditional access packet.

Abstract: A computer system includes a Key Certification Agency (KCA) (12), a host computer (16), and a number of remote terminals (14). The KCA (12) uses incompatible encryption processes (96, 98) to encrypt session control data and to store the data as various messages (44, 46, 48) in a user token (26). The token (26) may be removably installed in any remote terminal (14). To set up a communication session, the token uncovers one of the messages (48) using a crypto-uncovering agent which is known to the user. This message includes a remote traffic key after deciphering, but the key is never transmitted to the host. The host (16) deciphers the other messages (44, 46) and constructs a host traffic key in response to data contained therein. No plain text is transmitted during the setup or the session.

Abstract: According to the present invention, there is provided an optical radar in which a beam intensity-changed with a preset waveform and having a two-dimensional spread is irradiated on a target measurement object, an optical image of light reflected by the target measurement object is formed on the light-receiving surface of an image pickup element having a sensitivity modulation function and is photoelectrically converted, the sensitivity of the image pickup element is modulated with the preset waveform using the sensitivity modulation function of the image pickup element, distances to respective points of the target measurement object are obtained from light amount signals from the respective points of the target measurement object, which signals are output from the image pickup element, thereby measuring the shape of the target measurement object, wherein distances to the respective points of the target measurement object are obtained from the plurality of light amount values of the respective points of the ta

Abstract: The invention provides a public-key cryptographic apparatus which does not leak information regarding a plaintext and can prevent an increase in block length. A quadratic residue calculation circuit calculates a residue when the square of the lower n-1 bits of the plaintext of n bits is divided by public-key, and an exclusive OR circuit calculates an exclusive OR of the least significant bit of a result of the calculation and the most significant bit of the plaintext. Then, public-key encipherment such as the RSA cryptosystem or a modified Rabin cryptosystem is performed twice repetitively for totaling n bits of the output of exclusive OR circuit and the lower n-1 bits of plaintext by public-key enciphering circuits so as to make it impossible to estimate the most significant bit of the plaintext from the ciphertext.

Abstract: A phase difference detection type rangefinder is provided which calculates a distance value of each subject of two or more subjects at different distances.

Abstract: An apparatus and a method for measuring a distance optically using a phase variation. The apparatus comprises a light emitting circuit for emitting a high-power intermittent pulse light beam to an object, a light receiving circuit for receiving a light beam reflected from the object, a signal generation/phase difference detection circuit for generating first and second pseudo intermittent pulse signals in response to a drive signal from the light emitting circuit and an output signal from the light receiving circuit, respectively, detecting a phase difference between the generated first and second pseudo intermittent pulse signals and measuring a phase-delayed time on the basis of the detected phase difference, and a controller for performing a control operation in response to an output signal from the signal generation/phase difference detection circuit.

Abstract: Blind access (100, 300, 400) to a desired encryption key of a predetermined first group member is provided to a second group. The first group encrypts a plurality of first group member encryption keys using a predetermined algorithm and transfers to the second group, the encrypted plurality of first group member encryption keys with corresponding unencrypted first group member identification fields, IDs, and a list of IDs corresponding to the first group members. The desired ID-free encryption key is selected and encrypted by the second group using a predetermined algorithm. The doubly encrypted key is transferred to the first group, decrypted by the first group and transferred to the second group for decryption. Thus, the encryption key is provided without knowledge to the first group of which member's encryption key is being examined and with knowledge to the second group of only the desired encryption key.