An example process includes breaking content into multiple fragments; and transmitting at least two of the multiple fragments over different physical channels in order to isolate the at least two fragments during transmission. The example process may include generating session keys; encrypting at least some of the fragments using different session keys; and associating, with each fragment, a session key used to encrypt a different fragment to produce fragment/session key pairs.

There is provided a cryptographic key determination device for determining one or more cryptographic keys in a cryptographic device, the cryptographic device being configured to execute one or more test programs, the cryptographic device comprising one or more components (11-i), each component (11-i) being configured to generate static and dynamic data, the dynamic data being generated in response to the execution of the one or more test programs, wherein the cryptographic key determination device comprises: a data extraction unit configured to extract at least one part of the static data and at least one part of the dynamic data generated by the one or more components (11-i), and a key generator configured to combine the at least one part of static data and the at least one part of dynamic data, and to determine the one or more cryptographic keys by applying a cryptographic function to the combined data.

Systems, methods, and computer-readable media for achieving privacy for both data and an algorithm that operates on the data. A system can involve receiving an algorithm from an algorithm provider and receiving data from a data provider, dividing the algorithm into a first algorithm subset and a second algorithm subset and dividing the data into a first data subset and a second data subset, sending the first algorithm subset and the first data subset to the algorithm provider and sending the second algorithm subset and the second data subset to the data provider, receiving a first partial result from the algorithm provider based on the first algorithm subset and first data subset and receiving a second partial result from the data provider based on the second algorithm subset and the second data subset, and determining a combined result based on the first partial result and the second partial result.

In one embodiment, data communication apparatus includes a network interface for connection to a network and configured to receive a sequence of data packets from a remote device over the network, the sequence including data blocks, ones of the data blocks having block boundaries that are not aligned with payload boundaries of the packets, and packet processing circuitry to cryptographically process the data blocks using a block cipher so as to write corresponding cryptographically processed data blocks to a memory, while holding segments of respective ones of the received data blocks in the memory, such that the packet processing circuitry stores a first segment of a data block of a first packet in the memory until a second packet is received, and then cryptographically processes the first and second segments together so as to write a corresponding cryptographically processed data block to the memory.

The present description relates to systems and techniques for allowing a third party verifier to verify aspects of secured data, or successful communication thereof. For example, a message or other data may be associated with a shared manifest that describes aspects of some data but does not reveal or expose the data. As a result, the data may be kept private while selective privacy and verification with respect to the data is achieved by the inclusion of only selected aspects of said data in the shared manifest.

A security device may be utilized to provide security measures to an electronic device that may incorporate the security device or be coupled to it. The security measures may comprise authentication (e.g., authentication of devices, users, or activities), and/or encryption measures (e.g., encrypting or decrypting exchanged data). A transaction or access via the security device may be authenticated by communicating an authentication request by the security device to an authentication server, which may generate, in response, a sequence of information requests that are sent to the security device. The security device may then generate, in response, a sequence of responses that are sent to the authentication server, with the sequence of responses comprising a sequence of reported values each of which are unique. The authentication server may then authenticate the security device based on comparing of the sequence of reported values with a sequence of expected values that identifies the security device.

Methods, systems and computer program products for improving performance of a cryptographic algorithm are described. First, data to be encrypted/decrypted is provided as input to the system. A primary key, or multiple keys (in case of asymmetric cryptography), is generated for the encryption/decryption process. The primary key consists of metadata as well as key blocks containing secondary keys. The metadata contains information explaining how the data will be handled from algorithmic structure to the base cryptographic scheme to be used. Further, the data is split and processed via relevant portions of the key blocks. Finally, the completed encrypted/decrypted data segments are combined in order to complete the process. The used process ensures higher performance as well as higher algorithmic entropy than comparable methods in literature or on the market.

A method for determining a cryptographic key is carried out in a data processing system, and comprises: providing a plaintext and a ciphertext determined from the plaintext using a cryptographic key and a cryptographic procedure which comprises cryptographic operations; for each cryptographic operation of the cryptographic procedure, providing at least one intermediate relation which comprises an intermediate equation and/or an intermediate inequality; determining an optimization problem comprising: the plaintext and the ciphertext; at least one optimization expression assigned to a round of the cryptographic procedure; and optimization variables comprising state variables of the cryptographic procedure and a cryptographic key variable; wherein the at least one optimization expression is determined from the at least one intermediate relation and comprises at least one preceding state variable assigned to a preceding round. The method further comprises: solving the optimization problem and determining the cryptographic key from an optimizing value of the cryptographic key variable.

Systems and methods for protecting block cipher computation operations from external monitoring attacks. An example apparatus for implementing a block cipher may comprise a memory device to store instructions for computing a block cipher; and a processing device coupled to the memory device. The processing device performs a Data Encryption Standard (DES) cryptographic operation with multiple rounds of a Feistel structure, each round including a substitution function and a transformation function that combines an expansion function and a permutation function into a single operation. The transformation function transforms a first input portion of an internal state of the respective round and a second input portion of the internal state into a first output portion and a second output portion of data. The second output portion is equal to the first input portion and the first output portion is dependent on a combined permutation output from the transformation function.

A system and method for training a decision tree are disclosed. A method includes publishing, by a first party, a first set of nominated cut-off values at a current node of a decision tree to be trained, computing a first respective impurity value for the first set of nominated cut-off values at the current node, creating first respective n shares of the first respective impurity value, transmitting, from the first party and so a second party, one of the first respective n shares of the first respective impurity value, receiving from the second party one of a second respective n shares of the second respective impurity value, adding a group of impurity values to yield a combined impurity value based on the one of the first respective n shares and the one of the second respective n shares and determining, based on the combined impurity value, a best threshold.