Blockchain

A simple blockchain implementation using Python

There are 3 files in this repository:

• main.py

  This is the main file that is used to run the program. Asks the user to input the number of blocks to add and then asks for the data for each of those blocks.

  The output of the file is as follows:

  index  time_of_block_creation
  data_entered
  block_sha256_hash

• block.py

  Contains the Block class. Has a calculate_hash method that creates an SHA-256 hash using the index, timestamp, previous hash and the data entered and returns it. Also has a real_time method that simply takes the timestamp and prints it out as readable date and time.

• blockchain.py

  The __init__ method creates a new list with a genesis block.
  Contains is_valid method that checks if the new block has the correct hash and whether it is allowed to be added to the blockchain.
  The add_block method appends a new block to the chain if and only if it is valid (checked by is_valid).
  The print_blockchain method simply pretty prints the complete chain as shown in main.py.

Running the program in the terminal