International Business Machines Corporation
Computing range queries over encrypted data

Abstract:

A method (and structure and computer product) to encrypt plaintext data into ciphertext data includes encrypting, using a processor on a computer, plaintext into corresponding ciphertext, using a Property Preserving Encryption (PPE) protocol in which a predefined property is maintained when plaintext values are encrypted into ciphertext values. The predefined property is randomly flipped during encryption to reverse the predefined property in the corresponding ciphertext node. An indication of whether the predefined property has been maintained or reversed is stored as the state of encryption.