Abstract: There is provided a method of privacy-preserving logistic regression training based on homomorphically encrypted ciphertexts. The method includes: obtaining a first packed ciphertext comprising at least a portion of a first training data sample packed into a first vector of slots thereof for training a privacy-preserving logistic regression model; obtaining a second packed ciphertext comprising a plurality of weights of the privacy-preserving logistic regression model packed into a first vector of slots thereof; determining at least a first output probability of the privacy-preserving logistic regression model based on the first packed ciphertext and the second packed ciphertext; and updating the plurality of weights based on the first output probability. There is also provided a corresponding system for privacy-preserving logistic regression training based on homomorphically encrypted data.

Abstract: In some aspects, a set of input elements is obtained, at a rectified linear unit-activated neuron of a neural network based, on input data at the neuron. A first group and a second group of input elements are generated based on the set of input elements. The first group and the second group of input elements are associated with first weight elements and second weight elements, respectively. A first value is generated based on the first group of input elements and the first weight elements. A second value is generated based on the second group of input elements and the second weight elements. A third value and a fourth value are respectively generated based on a first operation and a second operation on the first value and the second value. An output of the neuron is generated based on the third value and the fourth value.

Abstract: There is provided a device for processing homomorphically encrypted data.

Abstract: Efficient polynomial multiplication for Accelerated Fully Homomorphic Encryption (FHE). An efficient method for large integer and polynomial multiplication in a ring using negacyclic convolution and discrete Galois transform with arbitrary primes is described. The method is adapted to work with arbitrary primes that support Gaussian arithmetic. Dealing with non-Gaussian primes gives rise to another problem of how to find primitive roots of unity and of (i). An efficient solution to find those roots of interest is provided.

Abstract: There is provided a method of determining an order of encrypted inputs, including a first encrypted input and a second encrypted input, using at least one processor, the first encrypted input including a first encrypted data and the second encrypted input including a second encrypted data, each of the first and second encrypted data being encrypted based on a homomorphic encryption scheme, the method including: generating a first series of encrypted blocks from the first encrypted data and a second series of encrypted blocks from the second encrypted data; performing a first block-wise operation between the first series of encrypted blocks and the second series of encrypted blocks to obtain a first series of block-wise outputs; performing a second block-wise operation between the first series of encrypted blocks and the second series of encrypted blocks to obtain a second series of block-wise outputs; and determining an order of the first and second encrypted data based on the first series of block-wise outpu

Abstract: Efficient polynomial multiplication for Accelerated Fully Homomorphic Encryption (FHE). An efficient method for large integer and polynomial multiplication in a ring using negacyclic convolution and discrete Galois transform with arbitrary primes is described. The method is adapted to work with arbitrary primes that support Gaussian arithmetic. Dealing with non-Gaussian primes gives rise to another problem of how to find primitive roots of unity and of (i). An efficient solution to find those roots of interest is provided.

Abstract: An access control method, which may be applied in a cloud environment, is provided in various embodiments. The access control method includes: receiving from a user a request for access to a resource; determining a group access key related to the resource; determining a user key of the user; determining whether the group key is an integer multiple of the user key; and granting the user access to the resource if it is determined that the group access key is an integer multiple of the user key.

Abstract: There is provided a method of generating a ciphertext. The method includes encrypting an input data to produce an encrypted data, and randomizing the encrypted data to produce the ciphertext. In particular, the randomizing process includes performing an exclusive-or (xor) operation on the encrypted data with a cipher pad, whereby the cipher pad is generated based on an xor-homomorphic function of a first key using a second key generated based on the encrypted data. There is also provided a corresponding system for generating a ciphertext, a corresponding method and system for decrypting a ciphertext, and a corresponding method and system for searching ciphertexts in a database, such as at an untrusted server.

Abstract: Various aspects of this disclosure provide a method of encrypting data in a network system. The method may include generating within a trusted network of the network system an associated private key based on an attribute associated with an user, a homomorphically encrypted associated private key based on the associated private key via homomorphic encryption, and a homomorphic key pair. The method may also include transmitting the homomorphically encrypted associated private key from the trusted network to a non-trusted network of the network system. The method may further include generating within the trusted network encrypted data based on said data, and a homomorphically and attribute based encrypted control key. The method may further include transmitting the encrypted data, and the homomorphically and attribute based encrypted control key, from the trusted network to the non-trusted network.

Abstract: There is provided a method of generating a ciphertext. The method includes encrypting an input data to produce an encrypted data, and randomizing the encrypted data to produce the ciphertext. In particular, the randomizing process includes performing an exclusive-or (xor) operation on the encrypted data with a cipher pad, whereby the cipher pad is generated based on an xor-homomorphic function of a first key using a second key generated based on the encrypted data. There is also provided a corresponding system for generating a ciphertext, a corresponding method and system for decrypting a ciphertext, and a corresponding method and system for searching ciphertexts in a database, such as at an untrusted server.