Representation of user accounts 

In blockchain-based applications, user accounts are identified and authenticated using asymmetric key pairs. The private key is used to sign transactions on behalf of the user. Username and password-based accounts systems will not work in blockchain as it cannot be used to prove which user has sent a transaction. The demerits in using private-public key pair include that they are not user-friendly and if you lose the private key then there is no way to recover it. So, it adds a new responsibility for the users to secure their private key. The address of a user account acts as the account identifier on blockchain. The address of a user account is derived from the public key.