Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources. The most important and popular cloud service is data storage. Large data sets provide a lot of information extraction security and privacy concerns arise as users sensitive data are susceptible to both inside and outside attacks in cloud storage. However, encrypted data introduce new challenges for cloud data deduplication. Traditional deduplication scheme cannot work on encrypted data, which suffer from security weakness. To protect the confidentiality of the sensitive data while supporting deduplication, the convergent encryption technique has been proposed to encrypt the data before outsourcing. In this paper we propose a scheme to reduplicate encrypted data stored in cloud, which is the one of the data mining techniques for eliminating duplicate copies of redundant data to reduce the amount of storage space and save bandwidth. This technique can flexibly support data sharing with deduplication and it does not intrude the privacy of data holders. Using this project, we improve the efficiency and effectiveness of the deduplication on encrypted data.