Creates a new Block object and fill it with a data string and the previous hash.

Checks if the DB exists.

Creates the first BlockChain's Block.

Initialises the BlockChain struct.

Produces a pointer to a ProofOfWork object from a pointer to a BLock object.

Tool function that convert an int64 to an array of bytes.

For now, the difficulty is static but it will be computed through an algorithm soon.

Block object that contains byte represntation of the data, the hash of the previous Block object and its current hash.

BlackChain object that contains all the Block objects.

Iterator that allows us to go through the blockchain stored in the database.

ProofOfWork object used to write a block in the blockchain.