Abstract: Methods and systems for performing an operation on at least one homomorphically encrypted ciphertext, the method include determining, by a computing device, a value that is an initial approximation of a result of the operation on the at least one homomorphically encrypted ciphertext; and iteratively improving, by the computing device, the value using a recurrence relation wherein a number of iterations is determined based on a predetermined accuracy to minimize an approximation error.

Abstract: FHE APSI for intersecting a first party's relatively large dataset X and a second party's relatively small dataset Y with SIMD Re-randomization to prevent data leakage. The first party may use SIMD FHE to execute a simultaneous bin-by-bin comparison of the intersection Y ?X. The first party may use SIMD FHE to re-randomize each comparison bin by simultaneously executing cyclical rotations on a plurality of slots in each bin to generate randomized comparison bins. The second party, using a secret SIMD FHE key, may simultaneously decrypt the randomized comparison bins to reveal unencrypted randomized comparison bins each either indicating an all-slot full match or a mismatch, but no combination of partial-slot match and mismatch of the bin-to-bin comparison of X and Y to prevent data leakage.

Abstract: Methods and systems for improving homomorphic encryption include: receiving, by a computing device, a data set from at least two or more computing devices, each data set comprising: a plurality of encrypted identifiers, and a number indicating the number of the plurality of encrypted identifiers; creating, by the computing device, a single data set including each of the received data sets; creating, by the computing device, a common identifier vector that indicates each encrypted identifier in the single data set that has underlying unencrypted data that is the same in more than one of the received data sets; and transmitting, by the computing device, the common identifier vector to each of the at least two or more computing devices.

Abstract: A device, system and method for debugging a homomorphically encrypted (HE) program. The HE program comprising real ciphertext data and encrypted operations in the HE space (production mode) may be mapped to an equivalent plaintext program comprising equivalent pseudo-ciphertext data and pseudo-encrypted operations in the unencrypted space (simulation mode). The plaintext program may be executed in a first full pass in simulation model and a sampling of the HE program may be executed in a second partial pass in production mode, the results of which are compared. The HE program and/or mapping may be validated if the results of simulation and production mode match and debugged if the results do not match. An integrated development environment (IDE) may switch among the HE space (production mode), the unencrypted space (simulation mode), and a combination of both HE and unencrypted spaces simultaneously (simultaneous production-simulation mode).

Abstract: A device, system and method for linking encrypted data sets using common encrypted identifiers in encrypted space. A first and second parties' encrypted data sets may include first and second respective encrypted data and associated first and second respective encrypted identifiers. The first and second encrypted identifiers may be converted into a first and second respective sets of a plurality of elemental identifier components. Each of the plurality of elemental identifier components in each component set characterizes a distinct numeric property of the corresponding converted encrypted identifier. The first and second sets of the plurality of elemental identifier components may be composed, component-by-component, to generate a plurality of component-specific results.

Abstract: A system and method for secure searching in a semi-trusted environment by comparing first and second data (query and target data). A first data provider may map first secret data to a first plurality of tokens using a token codebook, concatenate the first plurality of tokens to generate a first token signature, and homomorphically encrypt the first token signature. A second data provider may map second data to a second plurality of tokens using the token codebook, concatenate the second plurality of tokens to generate a second token signature, and compare the homomorphically encrypted first token signature and an unencrypted or homomorphically encrypted second token signature to generate a homomorphically encrypted comparison. A trusted party may decrypt the homomorphically encrypted comparison, using a secret homomorphic decryption key, to determine if the token signatures match or not respectively indicating the search query is found or not in the target data.

Abstract: A system, method, and non-transitory computer readable storage medium for privacy preserving routing of a data packet. The data packet may comprise a packet header and a data payload; the packet header comprising at least a homomorphically encrypted final destination address of a final destination device. An intermediate routing device may receive the data packet. At the intermediate routing device, in a non-TEE, homomorphic computations may be performed to determine a homomorphically encrypted address of a next intermediate routing device. At the intermediate routing device, in a TEE, one or more secret homomorphic decryption keys may be stored and used to decrypt the homomorphically encrypted address of the next address of the next intermediate routing device. The data packet may be transmitted to the decrypted address of the next intermediate routing device according to an updated packet header with the unencrypted address of the next intermediate routing device in the sequence.

Abstract: Methods and systems for improving homomorphic encryption include: receiving, by a computing device, a data set from at least two or more computing devices, each data set comprising: a plurality of encrypted identifiers, and a number indicating the number of the plurality of encrypted identifiers; creating, by the computing device, a single data set including each of the received data sets; creating, by the computing device, a common identifier vector that indicates each encrypted identifier in the single data set that has underlying unencrypted data that is the same in more than one of the received data sets; and transmitting, by the computing device, the common identifier vector to each of the at least two or more computing devices.

Abstract: A device, system and method for securely executing recursive computations over encrypted data in a homomorphically encrypted (HE) space. For a recursive algorithm with sequentially dependent recursive iterations, executing the recursive algorithm in parallel by computing multiple recursive iterations simultaneously over multiple parallel execution iterations and not in sequential order. Each parallel execution iteration may compute a partial HE solution of multiple sequential recursive iterations comprising a known HE part and leaves empty a placeholder call slot for an unknown HE part. Placeholder call slots remain empty and are filled at delayed times at a later parallel execution iteration from when the known part of the same HE computation is computed. A final HE solution is computed in fewer multiple parallel execution iterations than the number of sequential recursive iterations, thereby accelerating the recursive algorithm in HE space.

Abstract: Methods and systems for performing an operation on at least one homomorphically encrypted ciphertext, the method include determining, by a computing device, a value that is an initial approximation of a result of the operation on the at least one homomorphically encrypted ciphertext; and iteratively improving, by the computing device, the value using a recurrence relation wherein a number of iterations is determined based on a predetermined accuracy to minimize an approximation error.

Abstract: A device, system and method for linking encrypted data sets using common encrypted identifiers in encrypted space. A first and second parties' encrypted data sets may include first and second respective encrypted data and associated first and second respective encrypted identifiers. The first and second encrypted identifiers may be converted into a first and second respective sets of a plurality of elemental identifier components. Each of the plurality of elemental identifier components in each component set characterizes a distinct numeric property of the corresponding converted encrypted identifier. The first and second sets of the plurality of elemental identifier components may be composed, component-by-component, to generate a plurality of component-specific results.

Abstract: A device, system and method for linking encrypted data sets using common encrypted identifiers in encrypted space. A first and second parties' encrypted data sets may include first and second respective encrypted data and associated first and second respective encrypted identifiers. The first and second encrypted identifiers may be converted into a first and second respective sets of a plurality of elemental identifier components. Each of the plurality of elemental identifier components in each component set characterizes a distinct numeric property of the corresponding converted encrypted identifier. The first and second sets of the plurality of elemental identifier components may be composed, component-by-component, to generate a plurality of component-specific results.

Abstract: A method of protecting a computer system from fraudulent use includes collecting and aggregating sets of risk predictor values for user-initiated events into user-specific aggregations and organization-wide aggregations, and in response to a current event initiated by a user, generating a risk indicator as a combination of a user-specific indicator and an organization-wide indicator based on current event parameters and the user-specific and organization-wide aggregations. Based on the risk indicator indicating that the current event may be a fraudulent use, a protective control action is taken (such as denying or modifying a requested access) to protect the computer system.

Abstract: An improved technique involves including implicit feedback inferred from a fraud analyst's actions into a fraud detection model tuning process. Along these lines, as part of a tuning process, an authentication server sends electronic transactions carrying a certain amount of risk to a case management center in which fraud analysts investigate the electronic transactions to verify whether the transactions are fraudulent or non-fraudulent. In addition to receiving this explicit feedback from the case management center, however, the authentication server also receives implicit feedback indicative of attributes of the fraud analysts themselves. The authentication server then inputs these implicit feedback parameter values into a fraud detection model tuning engine that tunes the fraud detection model.

Abstract: A device, system and method for debugging a homomorphically encrypted (HE) program. The HE program comprising real ciphertext data and encrypted operations in the HE space (production mode) may be mapped to an equivalent plaintext program comprising equivalent pseudo-ciphertext data and pseudo-encrypted operations in the unencrypted space (simulation mode). The plaintext program may be executed in a first full pass in simulation model and a sampling of the HE program may be executed in a second partial pass in production mode, the results of which are compared. The HE program and/or mapping may be validated if the results of simulation and production mode match and debugged if the results do not match. An integrated development environment (IDE) may switch among the HE space (production mode), the unencrypted space (simulation mode), and a combination of both HE and unencrypted spaces simultaneously (simultaneous production-simulation mode).

Abstract: A system, method, and non-transitory computer readable storage medium for privacy preserving routing of a data packet. The data packet may comprise a packet header and a data payload; the packet header comprising at least a homomorphically encrypted final destination address of a final destination device. An intermediate routing device may receive the data packet. At the intermediate routing device, in a non-TEE, homomorphic computations may be performed to determine a homomorphically encrypted address of a next intermediate routing device. At the intermediate routing device, in a TEE, one or more secret homomorphic decryption keys may be stored and used to decrypt the homomorphically encrypted address of the next address of the next intermediate routing device. The data packet may be transmitted to the decrypted address of the next intermediate routing device according to an updated packet header with the unencrypted address of the next intermediate routing device in the sequence.

Abstract: A method involves performing a mathematical estimation operation identifying a risk score threshold. The operation identifies the risk score threshold as a point on a curve rather than a value of a particular risk score. Such a curve approximates the distribution of risk score values output over a time interval and represents a function embodied by a plot of risk score percentile vs. risk score value. The risk engine, rather than selecting a particular risk score, selects a curve from a family of curves that is known to accurately represent such risk score distributions. For example, the risk engine may choose the curve that provides the best fit to the previous week's risk scores over the family of curves. The risk engine identifies the risk score threshold by finding a risk score value such that the function evaluated at that risk score value produces a specified risk score percentile.

Abstract: A device, system and method for securely executing recursive computations over encrypted data in a homomorphically encrypted (HE) space. For a recursive algorithm with sequentially dependent recursive iterations, executing the recursive algorithm in parallel by computing multiple recursive iterations simultaneously over multiple parallel execution iterations and not in sequential order. Each parallel execution iteration may compute a partial HE solution of multiple sequential recursive iterations comprising a known HE part and leaves empty a placeholder call slot for an unknown HE part. Placeholder call slots remain empty and are filled at delayed times at a later parallel execution iteration from when the known part of the same HE computation is computed. A final HE solution is computed in fewer multiple parallel execution iterations than the number of sequential recursive iterations, thereby accelerating the recursive algorithm in HE space.

Abstract: A device, system and method for linking encrypted data sets using common encrypted identifiers in encrypted space. A first and second parties' encrypted data sets may include first and second respective encrypted data and associated first and second respective encrypted identifiers. The first and second encrypted identifiers may be converted into a first and second respective sets of a plurality of elemental identifier components. Each of the plurality of elemental identifier components in each component set characterizes a distinct numeric property of the corresponding converted encrypted identifier. The first and second sets of the plurality of elemental identifier components may be composed, component-by-component, to generate a plurality of component-specific results.

Abstract: Methods and apparatus are provided for validating event scenarios using reference readings obtained from a plurality of sensors associated with one or more predefined event scenarios. If a reading from a first sensor satisfies a reference reading of the first sensor for at least one identified scenario in a scenario library, at least one additional sensor is identified from the identified scenario and a reading is obtained from the additional sensors. The identified scenario is validated when the readings of the additional sensors satisfy the reference reading for the additional sensors from the identified scenario. A confidence level is optionally determined based on the readings of the sensors in the identified scenario. The readings of the sensors are optionally monitored over time to update the confidence level of the identified scenario.