Foundations of Blockchain

Block and blockchain interface

The Block and Blockchain class methods are similar to those used in the previous chapter to build a simple blockchain, with the only enhancement being the validation methods used to validate the received blocks.

The following method is invoked to verify that every block is linked to its previous block:

    def is_valid_new_block(self, new_block, previous_block): 

The following condition validates the index of the new block:

        if previous_block.index + 1 != new_block.index: 
            logger.warning('invalid index') 
            return False 

This condition performs hash validation by comparing the hash values of the blocks:

        if previous_block.hash != new_block.previous_hash: 
            logger.warning('invalid previous hash') 
            return False 

This condition ...