I'am working on searchable encryption.
First I create an index for a set of files. The index is B+ tree. The leaf of this tree is a bloom filter which represents the words in each file. Each bloom filter represents one file. Inner nodes represent XOR of these leaf nodes.
Last but not least: to encrypt this tree, I'ld like to encrypt each leaf node separately, but I'm confused which techniqe should be used to encrypt the inner nodes – while keeping it easy to do searches in this tree. What is the best technique I can use to encrypt inner nodes in B+tree?