A search scheme resulting in mixing compressed text files

The direct search of text files is a very useful technique. That not only reduces the amount of storage space required for a text file, but it also speeds up the search time. Furthermore, protecting secret documents is a basic and important requirement of computer systems. In this paper, we present a more secure compression and decompression technique for large natural language texts. The merits of our method are: (1) The word-based approximate matching process can be performed directly on the secure compressed text directly; (2) updating a word directly into the compressed text is supported; (3) the decompression process can be started at the position of the search results; (4) the search process does not require complex encryption computation. The scheme we present is simple. The complexity of the search phase is only O(n), which makes our scheme very practical. We believe that this technique has a great potential for its applications to be extended to solve other problems, for example, the private information retrieval problem, encrypted databases and so on.