After-deletion data recovery: myths and solutions

Abstract

Data security is primarily concerned with restricting unauthorised access to information – both persistent and transient. Persistent information is more vulnerable to attack as the prey is always available to the predator. That is why the ‘delete’ key exists. However, simple file deletion is not enough to ensure data security. 1 Operating systems give an illusion of file deletion by just invalidating the filename and stripping it of the allocated data blocks. This means the information residing within these data blocks exists even after file deletion. These data blocks may be allocated to some new file in future and, finally, may get overwritten with new information. Sometimes this time gap is beneficial as it allows recovery of files deleted accidentally. However, this time gap also allows malicious users to recover the confidential and sensitive information residing within deleted files.