Agency for Science, Technology and Research

Sivaraman Sundaram

Khin Mi Mi Aung

Shuqin Ren

Rodel Miguel

Benjamin Hong Meng Tan

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.

Method and system for generating/decrypting ciphertext, and method and system for searching ciphertexts in a database

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.

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Singapore, Singapore

Sivaraman Sundaram