Deleted Data Attribution in Cloud Computing Platforms

The introduction of Cloud-based storage represents one of the most discussed challenges among digital forensic professionals. In a 2014 report, the National Institute of Standards and Technology (NIST) highlighted the various forensic challenges created as a consequence of sharing storage area among cloud users. One critical issue discussed in the report is how to recognize a file's owner after the file has been deleted. When a file is deleted, the cloud system also deletes the file metadata. After metadata has been deleted, no one can know who owned the file. This critical issue has introduced some difficulties in the deleted data acquisition process. For example, if a cloud user accidently deletes a file, it is difficult to recover the file. More importantly, it is even more difficult to identify the actual cloud user that owned the file. In addition, forensic investigators encounter numerous obstacles if a deleted file was to be used as evidence against a crime suspect. Unfortunately, few studies have been conducted to solve this matter. As a result, this work presents our proposed solution to the challenge of attributing deleted files to their specific users. We call this the “user signature” approach. This approach aims to enhance the deleted data acquisition process in cloud computing environments by specifically attributing files to the corresponding user.