基于B+树的频率隐藏保序加密方案OA

Aiming at the problems that existing frequency-hiding order-preserving encryption(FH-OPE)schemes usually have large time overhead or high client storage overhead and poor performance balance,a frequency-hiding order-preserving encryp-tion scheme based on B+tree is proposed.It does not require additional client storage,uses B+tree as the coding tree and pro-poses a corresponding coding strategy.In the data insertion stage,the leaf number and the position of the ciphertext in the leaf are used as the order-preserving code.To address the coding update problem that may arise when a leaf splits,a new leaf number generation mechanism is designed so that when there are available numbers,only the coding of the data in the leaf needs to be updated locally without affecting other nodes.In addition,the scheme uses a slow update strategy.When there are no available leaf numbers and a global update of the leaf numbers is required,only the latest state of the coding tree is maintained and syn-chronized to the database with a delay,avoiding the large computational overhead caused by the global coding update and further improving the overall encryption efficiency of the scheme.Finally,the national encryption SM4-CBC algorithm is used to ran-domly encrypt the data to achieve autonomous and controllable solutions.Experimental results analysis demonstrate that,in com-parison with existing order-preserving encryption schemes,the proposed approach effectively conceals plaintext frequency while balancing time and space complexity,thereby offering a more well-rounded performance profile.