Abstract: A method of establishing a secure channel between a human user and a computer application is described. A secret unique identifier (“PIN”) is shared between a user and an application. When the user makes a request that involves utilizing the PIN for authentication purposes, the application renders a randomly selected identifier. The randomly selected identifier is in a format that is recognizable to a human but is not readily recognizable by an automated agent. The randomly selected identifier is then presented to the human user. The user identifies the relationship between the randomly selected identifier and the PIN. If the user's input reflects the fact that the user knows the PIN, then the user is authenticated.

Abstract: Systems and methods are provided for authentication by combining a Reverse Turing Test (RTT) with password-based user authentication protocols to provide improved resistance to brute force attacks. In accordance with one embodiment of the invention, a method is provided for user authentication, the method including receiving a username/password pair associated with a user; requesting one or more responses to a first Reverse Turing Test (RTT); and granting access to the user if a valid response to the first RTT is received and the username/password pair is valid.

Abstract: A method and system for preserving the integrity of a negotiation that includes providing an architecture which includes a center A, and a plurality of users B.sub.1, B.sub.2, . . . , B.sub.n. each user B.sub.i generates an input X.sub.i, which is input to the center A. The center A computes and publishes a function F(X.sub.1, X.sub.2, . . . , X.sub.n) based on the input messages it receives. Each user B.sub.i (1<=i<=n) communicates with the center A, exclusively. Center A publishes additional information which lets each of the users verify that F was computed correctly, and prevents a coalition of any one subset of the users from learning anything which cannot be computed just from the output of the function, F(X.sub.1, . . . ,X.sub.n), and from their own inputs, or information about the inputs of other users.

Abstract: Systems and methods are provided for managing the transfer of electronic files. In one embodiment, a sender transfers an encrypted version of a file (such as a digitally encoded audio track, movie, document, or the like) to someone who wishes to receive it. The receiver computes a hash of the encrypted file, and sends it to a trusted third party. The trusted third party compares the hash that was computed by the receiver with another hash computed by the sender. If the two hashes match, the third party sends the file decryption key to the receiver. In some embodiments, the receiver may also send the third party payment information so that the sender, the content owner, and/or the third party can be paid for their role in the transaction. In a preferred embodiment, the payment information is only sent to, and/or used by, the third party once the third party has confirmed to the satisfaction of the receiver that the encrypted file in the receiver's possession will decrypt correctly.

Abstract: A system and method for confidentially keyword searching information residing in a remote server processing system are disclosed. Briefly described, one embodiment is a method comprising receiving from a client system a keyword search request having at least one searchword; mapping a plurality of items to at least one of L bins using a function (H), the items residing in a dataset and comprised of item pairs (xi, pi), such that the item pairs are mapped to the bin H(xi); for the bins, defining at least one polynomial as a function of the items mapped into the bins; evaluating at least one of the polynomials at the searchword using an oblivious polynomial evaluation (OPE) protocol; and determining presence of at least one match between the searchword and one of the xi based upon the evaluation.

Abstract: A method of establishing a secure channel between a human user and a computer application is described. A secret unique identifier (“PIN”) is shared between a user and an application. When the user makes a request that involves utilizing the PIN for authentication purposes, the application renders a randomly selected identifier. The randomly selected identifier is in a format that is recognizable to a human but is not readily recognizable by an automated agent. The randomly selected identifier is then presented to the human user. The user identifies the relationship between the randomly selected identifier and the PIN. If the user's input reflects the fact that the user knows the PIN, then the user is authenticated.

Abstract: Systems and methods are provided for managing the transfer of electronic files. In one embodiment, a sender transfers an encrypted version of a file (such as a digitally encoded audio track, movie, document, or the like) to someone who wishes to receive it. The receiver computes a hash of the encrypted file, and sends it to a trusted third party. The trusted third party compares the hash that was computed by the receiver with another hash computed by the sender. If the two hashes match, the third party sends the file decryption key to the receiver. In some embodiments, the receiver may also send the third party payment information so that the sender, the content owner, and/or the third party can be paid for their role in the transaction. In a preferred embodiment, the payment information is only sent to, and/or used by, the third party once the third party has confirmed to the satisfaction of the receiver that the encrypted file in the receiver's possession will decrypt correctly.

Abstract: A system and method for confidentially matching information among parties are disclosed. Briefly described, one embodiment is a method comprising receiving from a first party a list of items, determining an encrypted polynomial P(y) from the first party's list of items, communicating the encrypted polynomial P(y) to a second party, receiving from the second party a list of second items, evaluating the encrypted polynomial P(y) at points defined by the second party's list of items, such that an output is determined, determining an encrypted output, the encrypted output corresponding to the output, communicating the encrypted output to the first party, decrypting the received encrypted output and determining an intersection between the first list of items and the second list of items based upon decryption of the received encrypted output.

Abstract: A system and method is disclosed for determining a value of an element, having a k-th rank. The method discloses: calculating a total number of elements in a first and second dataset; prohibiting parties from accessing each other's dataset; ranking the elements within each dataset; computing a total number of elements in the datasets each having a value less than a test value; computing a total number of elements in the datasets each having a value greater than the test value; and setting the value of the element, having the k-th rank, equal to the test value, if the total number of elements having values less than the test value is ? the k-th rank minus one, and the total number of elements having values greater than the test value is ? the total number of elements minus the k-th rank. The system discloses means for practicing the method.

Abstract: An authentication system and method for anonymous authentication of a data processing system from a group of data processing systems by a service provider are disclosed. A group key (110) is assigned to each data processing system (100) of the group of data processing systems. A service provider (120) is arranged to provide an encrypted authenticator (140) that is decryptable using the group key (110) to one of the data processing systems (100) to be authenticated and positively authenticate the data processing system upon receipt of data associated with the decrypted authenticator (130). Upon revocation of authentication rights of one of the data processing systems of the group, a new group key is distributed to the other data processing systems of the group using broadcast encryption.

Abstract: A method for secure multi-party function evaluation with a non-limiting application to the holding of auctions. The outcome of an auction can be determined by an auctioneer without learning any information about the bids, except for the bid which determines the clearing price, and without learning any information about the bidders, except for the winning bidder. The security of this information is maintained even after the conclusion of the auction. Moreover, the bidders can individually and privately verify that the auction was conducted correctly, thereby establishing a mechanism for trust. The method is well-suited to the holding of privacy-protected auctions over computer networks because of its high efficiency, requiring only a single round of interactive communication without any communication among the bidders. Furthermore, the bulk of the computation and data communication or the protocol can be done in advance of the auction itself, and is adaptable to distribution via stored media.

Abstract: A method of establishing a secure channel between a human user and a computer application is described. A secret unique identifier (“PIN”) is shared between a user and an application. When the user makes a request that involves utilizing the PIN for authentication purposes, the application renders a randomly selected identifier. The randomly selected identifier is in a format that is recognizable to a human but is not readily recognizable by an automated agent. The randomly selected identifier is then presented to the human user. The user identifies the relationship between the randomly selected identifier and the PIN. If the user's input reflects the fact that the user knows the PIN, then the user is authenticated.

Abstract: Systems and methods are provided for authentication by combining a Reverse Turing Test (RTT) with password-based user authentication protocols to provide improved resistance to brute force attacks. In accordance with one embodiment of the invention, a method is provided for user authentication, the method including receiving a username/password pair associated with a user; requesting one or more responses to a first Reverse Turing Test (RTT); and granting access to the user if a valid response to the first RTT is received and the username/password pair is valid.

Abstract: A computerized server selectively accepts service requests from clients connected to it by a communications network. In accordance with the present invention the permission to use a service is contingent on the requesting client performing a task which is easy to perform a limited number of times but is very costly to perform a large number of times. The server receives a service request from a client. The server also receives identifying information of that client, for example caller id information of a telephone number from which the client is further asked to call the server. The server examines data about previous service requests and the corresponding identifying information of clients. The request is approved if the requests with the same identifying information as the current request match a decision criterion for granting the request, for example if the number of these requests is below a predefined threshold.

Abstract: Systems and methods are provided for managing the transfer of electronic files. In one embodiment, a sender transfers an encrypted version of a file (such as a digitally encoded audio track, movie, document, or the like) to someone who wishes to receive it. The receiver computes a hash of the encrypted file, and sends it to a trusted third party. The trusted third party compares the hash that was computed by the receiver with another hash computed by the sender. If the two hashes match, the third party sends the file decryption key to the receiver. In some embodiments, the receiver may also send the third party payment information so that the sender, the content owner, and/or the third party can be paid for their role in the transaction. In a preferred embodiment, the payment information is only sent to, and/or used by, the third party once the third party has confirmed to the satisfaction of the receiver that the encrypted file in the receiver's possession will decrypt correctly.

Abstract: A method for secure accounting and auditing of a communications network operates in an environment in which many servers serve an even larger number of clients (e.g. the web), and are required to meter the interaction between servers and clients (e.g. counting the number of clients that were served by a server). The method (metering process) is very efficient and does not require extensive usage of any new communication channels. The metering is secure against fraud attempts by servers which inflate the number of their clients and against clients that attempt to disrupt the metering process. Several secure and efficient constructions of this method are based on efficient cryptographic techniques, are also very accurate, and preserver the privacy of the clients.