关键词: 密文数据库, 保序加密, 广义可变保序编码

Abstract: Privacy preserving in untrusted cloud environment has gradually aroused people’s attention. One of the major ways to solve this problem is to use encryption technology. Data are encrypted first and then are stored into database in cloud. However, it is necessary to find a way to operate and retrieve the encrypted data directly. A scheme, named as general mutable Order-Preserving Encoding（gmOPE）, is proposed. Based on generalized balanced binary tree, gmOPE allows user to choose a specific encryption algorithm and customize the adjustment strategy. And it can support order-related operations over the encrypted data efficiently by ensuring that the encrypted data keep the order of plain text. Meanwhile, it supports all kinds of data type and improves the efficiency of database operations by utilizing new rebalancing strategy. Experimental results show that gmOPE decreases the extra expense from re-coding and interaction between user and database and greatly improves the efficiency of encrypted database.

Key words: encrypted database, order-preserving encryption, general mutable order-preserving encoding