Data De-duplication is one of the effective ways now a days employed in the cloud computing. Energy consumption ratio of IT companies is increasing day by day and reason for it is storing redundant copy of data. Data De-duplication is a cutting edge technology that is used to remove redundant copies of data and store only unique copy of data. It reduces network bandwidth and storage space as well. There are many Data De-duplication methods used however in proposed work main focus is on block level Data De-duplication along with security. In Block level Data De-duplication redundancy would be checked based on blocks of data.

Now days due to advancement of storage technology and computer technology, larger fraction of data is being maintained in digitized form. The same data is stored over and over again, consuming unnecessary storage space on the disc. Deduplication is ideal for highly redundant operations like backup, which requires repeatedly coping and storing the same data. Data deduplication is one of the most alive topics in storage because it enables companies to save a lot of money on storage costs. For cloud provider it is very helpful because you can deduplicate what you store. Due to reduction in cost it is being more popular. This paper will briefly describe Data Deduplication and give a comprehensive survey.