Bitcoin was the first digital currency launched in 2008. This was the first decentralized currency managed by peer to peer network. The concept of blockchain was introduced which forms the backbone of the cryptocurrency.
Blockchain: Blockchain is public ledger which records the transaction of the bitcoin. The blockchain is add only account in which previous transaction are immutable or not editable. This blockchain gets downloaded to the machine who are called miners. The miners maintains the transactions and in return gets a cut for each transactions. The machine is called a node.
Consensus mechanism: For a transaction to be accepted in the blockchain, a miner has to propose it as a valid transaction and it should be accepted by a general consensus. When this happens, the transaction gets added in the blockchain and the money is transferred to the respective accounts, which are a part of the transactions.
Wallets: Wallets are the place where the bitcoins are kept. Wallets can be an exchange wallet, a hardware or a cold wallet, or a private wallet. The exchange wallet are wallet associated with the exchanges, where the buying and selling of the bitcoin can be done. The exchange help in converting the cryptocurrencies to fiat currencies. The hardware wallet or cold wallet are most secured form of wallet since it is not connected to the internet.
Hardware-wallet: As mentioned above, hardware wallets are the most secured way of keeping the cryptocurrencies. There are various harware wallets now-a-days, most famous being Nano Ledger S, Trezor, and KeepKey.
Crypto-Currency 