At its most basic core, the concept of a blockchain is understood to be a data structure that has the ability to maintain records of transactions, and all the time it is doing so, maintains a high level of security, decentralization, and transparency. The decentralized nature of the blockchain ensures that no part of it is controlled by any specific and singular authority, but rather a ledger that is open for viewing by anyone that uses it, i.e. a distributed ledger. One main benefit of the decentralized, distributed ledger is that it cannot be changed by any one person that would like to alter it, and thus it is safer from abuse than a centralized register is.
Digital signatures are used to secure each transaction that is performed on a blockchain in order to prove that the transaction is authentic. Information on a blockchain like a digital signature is encrypted and as such, it is safe from being tampered with and is unable to be changed. Agreements are reached across the blockchain by network participants in relation to reaching a consensus. Information which is stored on a blockchain is digitally recorded and the history of the blockchain transactions are common, available to all network participants. In this regard, there is no chance of having fraudulent activity or transaction duplication.
To understand the idea of blockchain a little better, one can consider what happens when you think about sending money to someone that lives far away from you. Contemporary options for this include PayPal, or by creating an electronic funds transfer through a bank account. Both of these options involves at least one third party to be involved in the process, which will by default mean that an additional fee is charged for the transaction by that third party. When you transfer money in these ways, you cannot guarantee the safety of the money because it becomes more possible for a hacker to intercept it than if you sent the money directly to the other person without any third party involvement. Using a blockchain is safer than using a bank.
Blockchain also does not charge any additional fees to transfer money, as you are the one who is processing the funds – making the transaction both easy and more secure. Blockchain databases are decentralized so they are not limited to any specific location, and all records and related information are publicly kept on the blockchain. This stops the information from being corrupted by someone as it could not be corrupted everywhere across the chain, and such an event is only possible in traditional centralized banking.