
Cloud computing is an important platform for the data owners to store their data from local sites to commercial public cloud providing high flexibility and economic savings. But the cloud storage systems are most vulnerable for the data security due to their internal data sharing among the servers. By applying strong cryptography techniques, data is stored in the cloud. But eventually this doesn't solve the problem of storing process as cloud provides big storage capacity, so performing the search on this huge encrypted data in the cloud is posing a real challenge. To solve this problem, many ideas are proposed to perform the search over the encrypted data, but no system is providing complete accuracy as this mainly depend on the document content. Here, some novel approaches are discussed and also an idea of constructing a special tree-based index structure is constructed that proposes a “Greedy Depth-first Search” algorithm that provides efficient multi-keyword ranked search.