Abstract: There is disclosed a method for use in credential recovery. In one exemplary embodiment, the method comprises determining a policy that requires at least one trusted entity to verify the identity of a first entity in order to facilitate credential recovery. The method also comprises receiving at least one communication that confirms verification of the identity of the first entity by at least one trusted entity. The method further comprises permitting credential recovery based on the received verification.

Abstract: Methods and apparatus are provided for signing data transactions using one-time authentication passcodes. User authentication passcodes are generated by generating a time-based user authentication passcode based on a forward-secure pseudorandom number, wherein the generated time-based user authentication passcode is used for authentication of the user; and generating an event-based user authentication passcode based on a forward-secure pseudorandom number, wherein the generated event-based user authentication passcode is used to sign one or more data transactions. The generation of an event-based user authentication passcode can be performed on-demand. The generation of the event-based user authentication passcode can optionally be performed substantially simultaneously with the generation of the time-based user authentication passcode.

Abstract: Methods and apparatus are provided for secure transmission of alert messages over a message locking channel. An alert message is transmitted from a Security Alerting System indicating a potential compromise of a protected resource by obtaining the alert message from the Security Alerting System; authenticating the alert message using a secret key known by a server, wherein the secret key evolves in a forward-secure manner; storing the authenticated alert message in a buffer; and transmitting the buffer to the server. The alert message is authenticated by digitally signing the alert message or applying a message authentication code and is possibly encrypted using a secret key known by a server, wherein the secret key evolves in a forward-secure manner. The authenticated alert message can be maintained in the buffer after the transmitting step. The buffer optionally has a fixed-size and alert messages can be stored in a round-robin manner, for example, from a random position.

Abstract: An improved search engine technique allows a user to ensure that an untrusted search engine provides complete and correct search results without requiring large proofs for large data collections. Thus techniques are presented for a trusted crawler to index a distributed collection of documents and create an authenticated search structure that allows an untrusted search server to return reliably complete and correct search results.

Abstract: There is disclosed a method for use in credential recovery. In one exemplary embodiment, the method comprises determining a policy that requires at least one trusted entity to verify the identity of a first entity in order to facilitate credential recovery. The method also comprises receiving at least one communication that confirms verification of the identity of the first entity by at least one trusted entity. The method further comprises permitting credential recovery based on the received verification.

Abstract: Methods and apparatus are provided for authenticating a user using multi-server one-time passcode verification. A user is authenticated by receiving authentication information from the user; and authenticating the user based on the received authentication information using at least two authentication servers, wherein the received authentication information is based on a secret shared between a security token associated with the user and an authentication authority that provides the at least two authentication servers. For example, the authentication information can comprise a passcode comprised of a tokencode from the security token and a password from the user. The user can be authenticated only if, for example, all of the at least two authentication servers authenticate the received authentication information.

Abstract: In one exemplary embodiment, an apparatus includes a memory storing data and a processor performing operations. The apparatus generates or maintains an accumulation tree for the stored data—an ordered tree structure with a root node, leaf nodes and internal nodes. Each leaf node corresponds to a portion of the data. A depth of the tree remains constant. A bound on a degree of each internal node is a function of a number of leaf nodes of a subtree rooted at the internal node. Each node of the tree has an accumulation value. Accumulation values of the root and internal nodes are determined by hierarchically employing an accumulator over the accumulation values of the nodes lying one level below the node in question. The accumulation value of the root node is a digest for the tree.

Abstract: Methods and apparatus are provided for generation of forward secure pseudorandom numbers that are resilient to such forward clock attacks. A forward secure pseudorandom number is generated by obtaining a first state si corresponding to a current leaf node ?i in a hierarchical tree, wherein the current leaf ?i produces a first pseudorandom number ri?1; updating the first state si to a second state si+t corresponding to a second leaf node ?i+t; and computing a second pseudorandom number ri+t?1 corresponding to the second leaf node ?i+t, wherein the second pseudorandom number ri+t?1 is based on a forward clock reset index that identifies an instance of the hierarchical tree, wherein the instance of the hierarchical tree is incremented when one or more criteria indicating a forward clock attack are detected. The forward clock reset index can be encoded in a forward secure manner in the hierarchical tree.

Abstract: Methods and apparatus are provided for authenticated hierarchical set operations. A third party server processes a query q (possibly from a client) on outsourced data sets S1, . . . , Sn on behalf of a source of the data. The query q comprises a hierarchical set operation. Authenticated Set Operation techniques for flat set operations can be iteratively applied for hierarchical set operations. In addition, bilinear accumulators are extended to provide an extractable accumulation scheme comprising a primary bilinear accumulator and a secondary bilinear accumulator. In addition, a query q is parsed as a tree and for each tree node, a Union/Intersection argument is provided that is related to one or more accumulation values associated with the corresponding tree node.

Abstract: Methods and apparatus are provided for fraud detection and remediation in knowledge-based authentication (KBA). A knowledge-based authentication method is performed by a server for restricting access of a user to a restricted resource. The exemplary knowledge-based authentication method comprises challenging the user with one or more questions requiring knowledge by the user; receiving a response from the user to the one or more questions, wherein at least a portion of the response is encoded by the user using an encoding scheme defined between the server and the user to signal a fraudulent access attempt; and granting access to the restricted resource if one or more predefined response criteria are satisfied, wherein the one or more predefined response criteria comprises an assessment of whether the encoded portion of the response satisfies the encoding scheme. A number of exemplary encoding schemes are disclosed.

Abstract: Knowledge-based authentication (KBA) is provided using historically-aware questionnaires. The KBA can obtain a plurality of historically different answers from the user to at least one question; challenge the user with the question for a given period of time; receive a response from the user to the question; and grant access to the restricted resource if the response is accurate for the given period of time based on the historically different answers. Alternatively, the KBA can be based on historically aware answers to a set of inter-related questions. The user is challenged with the inter-related questions for a given period of time. Historically different answers can comprise answers with applicable dates, or correct answers to the question over time. Historically aware answers can comprise an answer that is accurate for an indicated date or period of time. An accurate response demonstrates knowledge of multiple related personal events.

Abstract: Methods and apparatus are provided for generation of forward secure pseudorandom numbers. A forward secure pseudorandom number is generated by obtaining a first state si corresponding to a current leaf node vi in a hierarchical tree, wherein the current leaf vi produces a first pseudorandom number ri?t and wherein the hierarchical tree comprises at least one chain comprised of a plurality of nodes on a given level of the hierarchical tree; updating the first state si to a second state si+t corresponding to a second leaf node vi+t; and computing a second pseudorandom number ri+t?1 corresponding to the second leaf node vi+t. The variable t may be an integer greater than one. Updating the state does not require generation of all pseudorandom numbers produced by leaf nodes between the current leaf node vi and the second leaf node vi+t.

Abstract: A method is performed by a data server of a plurality of data servers connected to a network, the data server including data storage managed by a remote metadata server, the metadata server managing storage of data across the plurality of data servers. The method includes (a) receiving, via the network, an access request from a client, the access request requesting access to a portion of the data storage of the data server, (b) testing whether the access request includes a data server specific token authenticating that the client has been authorized by the metadata server to access the portion of data storage, and (c) in response to testing, providing the client with access to the portion of data storage on condition that the access request includes the token authenticating that the client has been authorized by the metadata server to access the portion of data storage.

Abstract: Methods and apparatus are provided for embedding auxiliary information in one-time passcode authentication tokens. Auxiliary information is embedded in authentication information transmitted to a receiver by obtaining the auxiliary information; and mapping the auxiliary information to a codeword using a secret key, wherein the secret key is shared between the security token and an authentication authority; and combining the codeword with a tokencode generated by a security token to generate a one-time passcode. The one-time passcode can then be transmitted to the receiver.

Abstract: Improved techniques are provided for the generation of exfiltration-resilient cryptographic keys. A method is provided for generating exfiltration-resilient cryptographic keys for authentication and/or digital signing. A set of authentication information sk[i] is stored in a device associated with a user and a set of public keys pk[i] are provided to a verifier corresponding to the set of authentication information sk[i], where sk[i] is mapped to pk[i] using a hash function. The device obtains a challenge from the verifier comprising a sequence C of k indices. A response is provided to the verifier comprising elements of the set of authentication information sk[i] corresponding to the k indices. The set of authentication information sk optionally has a size that satisfies one or more leakage-resilient criteria.

Abstract: A technique controls a soft token running within an electronic apparatus. The technique involves providing an initial series of authentication codes based on a first set of machine states. The initial series of authentication codes is provided from the electronic apparatus to a server through a forward channel to authenticate a user. The technique further involves receiving a command from the server through a reverse channel between the electronic apparatus and the server. The reverse channel provides communications in a direction opposite to that of the forward channel. The technique further involves changing the first set of machine states to a second set of machine states in response to the command, and providing a new series of authentication codes based on the second set of machine states. The new series of authentication codes is provided from the electronic apparatus to the server through the forward channel for user authentication.

Abstract: In one exemplary embodiment, an apparatus includes a memory storing data and a processor performing operations. The apparatus generates or maintains an accumulation tree for the stored data—an ordered tree structure with a root node, leaf nodes and internal nodes. Each leaf node corresponds to a portion of the data. A depth of the tree remains constant. A bound on a degree of each internal node is a function of a number of leaf nodes of a subtree rooted at the internal node. Each node of the tree has an accumulation value. Accumulation values of the root and internal nodes are determined by hierarchically employing an accumulator over the accumulation values of the nodes lying one level below the node in question. The accumulation value of the root node is a digest for the tree.

Abstract: An improved technique involves protecting a set of resources in a distributed computer system by scheduling epochs for replacing keys that have a variable duration. Along these lines, a Variable Epoch Scheduler (VES) generates schedules of key updates for a set of players in the distributed system such that at least two epochs in the schedules have different durations. For example, the epoch durations within a schedule may vary, or the epoch durations for different players may be different. At the end of each epoch, the VES notifies the distributed system to update the key identified in the schedule as corresponding to that epoch.

Abstract: An improved technique for managing access of a user of a computing machine to a remote network collects device posture information about the user's mobile device. The mobile device runs a soft token, and the collected posture information pertains to various aspects of the mobile device, such as the mobile device's hardware, software, environment, and/or users, for example. The server applies the collected device posture information along with token codes from the soft token in authenticating the user to the remote network.

Abstract: A processing device comprises a processor coupled to a memory and implements a graph-based approach to protection of a system comprising information technology infrastructure from a persistent security threat. Attack-escalation states of the persistent security threat are assigned to respective nodes in a graph, and defensive costs for preventing transitions between pairs of the nodes are assigned to respective edges in the graph. A minimum cut of the graph is computed, and a defensive strategy is determined based on the minimum cut. The system comprising information technology infrastructure subject to the persistent security threat is configured in accordance with the defensive strategy in order to deter the persistent security threat.