Abstract: A method includes, at a first communications device: processing encapsulation keys of a plurality of second communications devices using an encapsulation function to generate a symmetric key, an authenticable token, and a ciphertext; and transmitting, to each of the second communications devices, the token and a respective portion of the ciphertext depending on the respective encapsulation key of that second communications device. The token is a cryptographic commitment of the symmetric key, and the ciphertext is a multi-recipient encapsulation of the symmetric key under the encapsulation keys of the second communications devices. The method further includes, at each second communications device: processing the respective decapsulation key and the respective portion of the ciphertext using a decapsulation function to generate a respective candidate copy of the symmetric key; authenticating the token, whereby to determine that the respective candidate copy of the symmetric key corresponds to the symmetric key.

Abstract: Disclosed herein are method and systems for transmitting a plurality of ciphertexts to a plurality of users. The systems and methods described herein provide for performing an encryption update comprising a plurality of encryption keys and a multi-ciphertext to a plurality of recipient nodes. Methods and systems for organizing a database are also disclosed herein.

Abstract: Certain examples described herein relate to secure update propagation. The examples present systems and methods to transmit data in the form of updates over a network and to ensure the authenticity of the updates. The examples use a set-homomorphic digital signature scheme to sign updates such that a combined digital signature may be used to verify a batch of updates in place of a set of individual digital signatures. The combined digital signature may be generated by aggregating individual digital signatures.

Abstract: A key generation method is provided. A first peer obtains an ephemeral key from a second peer via a server. The first peer uses the ephemeral key to compute a ciphertext that encrypts a first parameter. The first peer uses the first parameter to generate a session key. The ciphertext is sent to the server by the first peer to allow the second peer to generate the session key. The key may be subsequently used for communication, such as by using a key management algorithm such as Double Rachet.

Abstract: Cryptographic methods and systems are described. An example cryptographic system may include a signature engine to digitally sign a message using fuzzy data associated with a signee. The signature engine is configured to generate a digital signature using a lattice instantiation and a linear sketch. The linear sketch is configured based on the lattice instantiation. The digital signature is a function of the fuzzy data and the message and uses a signature-time signing key residing within a signing key space. The signing key space is a space defined by the lattice instantiation. An example of a verification engine is also described. The verification engine is configured to receive the message and the digital signature and to verify the message as signed by the signee.

Abstract: Certain examples described herein relate to secure update propagation. The examples present systems and methods to transmit data in the form of updates over a network and to ensure the authenticity of the updates. The examples use a set-homomorphic digital signature scheme to sign updates such that a combined digital signature may be used to verify a batch of updates in place of a set of individual digital signatures. The combined digital signature may be generated by aggregating individual digital signatures.

Abstract: The disclosure relates to implementing an anonymous reputation system for managing user reviews. In one arrangement, an anonymous reputation system is constructed from a group of group signature schemes run in parallel. Each item of a plurality of items is associated uniquely with one of the group signature schemes. A user is allowed to join the group signature scheme associated with the item when information indicating that the user has performed a predetermined operation associated with the item is received. The user can submit a review of the item when the user has joined the group signature scheme associated with the item (6). The anonymous reputation system is publicly linkable and non-frameable (8a, 8b).

Abstract: Disclosure is a vehicle headlamp control system having a control circuit which can control the operation and the intensity of illumination of headlamps with ease. The vehicle headlamp control system has a control circuit for controlling the operations of headlamps on a vehicle at the start of the engine. The control circuit operates to adjust the duty ratios of driving pulse currents applied to the headlamps through transistors, thereby to adjust the intensities of illumination of the headlamps. The control circuit has elements for adjusting the duty ratios. With the system, the intensities of illumination of the headlamps can be adjusted with ease.