Abstract: A method and apparatus for generating a conformance test data sequence of minimal length to verify that a device conforms to a protocol entity which can be characterized by a simplified extended finite state machine. The method generates an expanded directed graph of the protocol wherein each state is represented by a state vertex and a dummy vertex which are connected to other similar state and dummy vertices by directed edges in a configuration corresponding to the operation of the machine. The directed edges are then assigned traversal numbers corresponding to the minimum number of times a respective directed edge need be traversed in order to test values in a predetermined test data set. The traversal numbers of the expanded directed graph are balanced to form a symmetric expanded directed graph. An Euler tour and a corresponding unique input-output sequence of the last state of the Euler tour are generated to form the conformance test data sequence.

Abstract: A forward error correction system adaptively changes the number of parity bits, bytes or packets transmitted to a receiver, based on previous error patterns experienced recently in the reception of original and parity bits, bytes or packets by that receiver.

Abstract: A wireless communications system is arranged to provide data communications services, including error recovery, between at least one wireless end-user device and at least one one base station. The wireless end user device(s) receives(s) from the base station(s) unsolicited messages indicative of the status of data packets received by the base station(s). The wireless end-user device(s) transmit acknowledgement and request for retransmission messages only upon request, or when all the packets within a block of such packets have been received.

Abstract: A method of network multicasting using transport layer protocols, suitable for use in ATM networks, is disclosed. The protocols advantageously combine the acknowledgments of individual destinations along the underlying multicast tree to prevent acknowledgement implosion. The inventive method also prevents unnecessary retransmission by performing local multicasts.

Abstract: A method for protecting electronically published documents involves operating a computer system and network for electronic publication of documents, and includes the steps of receiving requests for documents from users having computers with display devices or printers, including with the requests unique user identification for each of the user; authenticating the requests with a copyright server; using the copyright server to direct a document server to act upon proper authentication of each request; using the document server to create uniquely encoded, compressed and encrypted documents for each authenticated request, where the documents have unique encoding corresponding to each of the users, and forwarding the documents to each authenticated request user through the network to corresponding agents of each authenticated request user, with each of the agents being selected from display agents and printer agents; and decrypting and uncompressing the documents at each of the agents and making the documents ava

Abstract: Techniques for performing credit-card transactions without disclosing the subject matter of the transaction to the institution providing the credit card. The techniques include the use of a communications exchange so that information and funds may be transferred without the destination for the transfer knowing the source of the information or funds and the use of public key encryption so that each party to the transaction and the communications exchange can read only the information the party or the exchange needs for its role in the transaction. Also disclosed are techniques for authenticating a card holder by receiving personal information from the card holder, using the information to ask the card holder one or more questions, and using the answers to authenticate the card holder.