A A chain of custody refers to documentation or paper trail, in order of time, which shows the seizure, custody, control, transfer, analysis, and disposition of evidence. means that the A Blockchain computing system treats the Blockchain as a secure computation platform that can be shared among multiple vendors. transaction has been verified by the An overlay network is a computer network that is built on top of another network. Nodes in the overlay network are connected by virtual links. network. This happens through mining. Once a transaction is confirmed, it cannot be reversed, nor can it be double spent, which is necessary to preserve valid transactions.