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Blockchain Technology

Participants' documentation and replicas of the original digital evidence,

on the other hand, are primarily regarded. The current proofs are kept in a

safe place initially.

Phase 4 – Showcase Evidence: The showcase evidence function uses evidence

input ID and returns the blockchain proof information. The only measure is

to ensure that the proof exists now.

14.6  APPLYING BLOCKCHAIN FOR DISTRIBUTED

CLOUD STORAGE IN DIGITAL FORENSICS

With the advancement of technology, the volume of web data generated on a daily

basis is increasing tremendously. To handle this vast volume of data, most enter­

prises, application developers and consumers are choosing a cloud storage environ­

ment. A centralized cloud storage environment like Google cloud, ownCloud and

Dropbox provides the facility to access data anytime, anywhere. In centralized cloud

storage, the cost of data communication over the cloud is very high. Also, preserving

the security and privacy of private and sensitive data on the cloud has become a criti­

cal issue because along with the use of the cloud storage environment, the security

threat to the data has also increased. The recovery of data as well as collecting digi­

tal forensics is also very difficult for the forensics investigators because it involves

access to every bit of private and confidential data stored on the central cloud (Ricci

et al., 2019).

Along with centralized cloud storage, a new concept of distributed cloud storage is

emerging that uses blockchain technology, which is by default encrypted. In distrib­

uted cloud storage, the unused storage of one user can be offered on rent to another

user for storing their data. In this way, the user can take the unused storage space of

other users on rent preferably in his/her own geographic proximity. All users of dis­

tributed cloud storage are connected through a peer-to-peer network. This network

is more secure, faster and less expensive than centralized cloud storage. The block­

chain technology in distributed cloud storage ensures the confidentiality and integ­

rity of the data and provides verifiable temper-proof data without any middlemen.

In blockchain-based distributed cloud storage, everything that happens to the data,

like its different storage locations, details of owner and details of the person who

accesses that data, has been monitored. All these details of the data can be fetched

by anyone who has access to the blockchain. Despite this, the collection of digital

forensics on distributed cloud storage becomes more complicated. If the data is not

available or recoverable (in the case of deletion) from local storage, then the forensics

investigators need to recover the data and metadata from the distributed cloud stor­

age, which requires login credentials for getting access to the account, along with

the decryption keys and the information of all the locations where the encrypted data

chunks are stored over the distributed cloud. The forensics investigators also need

legal permission for all the storage locations separately. Also, if the data deletion

request has been sent by the user to the storage location on the distributed cloud, then

after the deletion of that data chunk, it will be impossible to determine the location

where those data chunks existed, given that there will be no metadata existing that