Blockchain uses cryptography to secure users’ identities and ensure transactions are done safely with a hash function.
Cryptography uses public and private keys in order to encrypt and decrypt data. In the Blockchain network, a public key can be shared with all the Bitcoin users but a private key (just like a password) is kept secret with the users.
Blockchain uses SHA - 256 which is secure and provides a unique hash output for every input. The basic feature of this algorithm is whatever input you pass, it will give you a standard alphanumeric output of 64 characters. It is a one-way function from which you can derive an encrypted value from the input, but not vice-versa.
