AVERAGE-COMPLEXITY IDEAL-SECURITY ORDER-PRESERVING ENCRYPTION

摘要

Embodiments provide ideal security, order-preserving encryption (OPE) of data of average complexity, thereby allowing processing of the encrypted data (e.g. at a database server in response to received queries). Particular embodiments achieve high encryption efficiency by processing plaintext in the order preserved by an existing compression dictionary already available to a database. Encryption is based upon use of a binary search tree of n nodes, to construct an order-preserving encryption scheme having Ω(n) complexity and even O(n), in the average case. A probability of computationally intensive updating (which renders conventional OPE impractical for ideal security) is substantially reduced by leveraging the demonstrated tendency of a height of the binary search tree to be tightly centered around O(log n). An embodiment utilizing such an encryption scheme is described in the context of a column-store, in-memory database architecture comprising n elements. OPE according to embodiments is compatible with adjustable encryption approaches.

主权项

1. A computer-implemented method comprising:
causing an engine on a client, to create a dictionary copy preserving an order of data stored in a database on a server; causing the engine to execute an algorithm encrypting the data on the dictionary copy according to the order; causing the engine to update the data stored in the database according to an update probability; causing the engine to create further encrypted data from the encrypted data; causing the engine to send the further encrypted data to the server; and causing the engine to send a cryptographic key to allow decryption of the further encrypted data.