Sample blockchain concept implementation from scratch

Main blockchain construction

• Implements a blockchain - in particular, a main loop that repeatedly obtains new data and computes and outputs the hash ​H(d)​ of data structure ​d​.
  • The data structure ​d​ must contain
    • hash of the previous block
    • A Merkle Tree
    • A nonce
    • The first 16 (binary) digits of each block hash must be 0.
  • Uses Elliptic Curve Cryptography (ECC) - (library provided)
• Implements Merkle Tree
  • The Merkle Tree must be build from all valid elements received from the DataSimulator, i.e. all valid ​(publicKey, message, signature)​ tuples where the signature is valid

Provides a Merkle Tree-proof

• A Merkle Tree-proof that a specific item is part of the Merkle Tree in an ancestor of the last block.
• In detail, given the created blockchain after 5 blocks, shows proof that the headline cabinet meets to balance budget priorities was “put on the blockchain.”

Sample output:

$ python3 run_blockchain.py 
================================================================================
genesis Hash =  0000c3cb141422f9736ff35e5fdda5a3 prevHash = 00000000000000000000000000000000 merkleTree-root = 1b31113d4865b2f04b82802702a7c555 nonce = 38032
================================================================================
prevHash = 0000c3cb141422f9736ff35e5fdda5a3 merkleTree-root = 881f2b580cb3db870f86eebbf67c7f0b nonce = 48348
--------------------------------------------------------------------------------
prevHash = 0000dd87ad348f335b2bd4957940d696 merkleTree-root = c0ca1303491a3c9346647fe90ba84adc nonce = 34893
--------------------------------------------------------------------------------
prevHash = 0000fec3ba530b2276e45a5a8c8b169f merkleTree-root = ccb7b3fc9646e62d46868481e105b97b nonce = 25596
--------------------------------------------------------------------------------
prevHash = 000064cd652e7633581b3fb2fcbd5e31 merkleTree-root = 0286ffabfb1af0184d7b8ab0637b748a nonce = 90084
--------------------------------------------------------------------------------
prevHash = 0000c33e9c69a46ddd8e4d1d65907b9b merkleTree-root = bee46a181a71875222bd87eb65aed5ad nonce = 21758
--------------------------------------------------------------------------------
prevHash = 0000066320056b688dc7a2048a6ea00d merkleTree-root = 662bd1be5c6c876be3c7a4373202c45b nonce = 23624
--------------------------------------------------------------------------------
================================================================================
Input data is in blockchain. The proof is:
================================================================================
The Blockchain: 
prevHash = 0000066320056b688dc7a2048a6ea00d merkleTree-root = 662bd1be5c6c876be3c7a4373202c45b nonce = 23624
prevHash = 0000c33e9c69a46ddd8e4d1d65907b9b merkleTree-root = bee46a181a71875222bd87eb65aed5ad nonce = 21758
prevHash = 000064cd652e7633581b3fb2fcbd5e31 merkleTree-root = 0286ffabfb1af0184d7b8ab0637b748a nonce = 90084
prevHash = 0000fec3ba530b2276e45a5a8c8b169f merkleTree-root = ccb7b3fc9646e62d46868481e105b97b nonce = 25596
prevHash = 0000dd87ad348f335b2bd4957940d696 merkleTree-root = c0ca1303491a3c9346647fe90ba84adc nonce = 34893
prevHash = 0000c3cb141422f9736ff35e5fdda5a3 merkleTree-root = 881f2b580cb3db870f86eebbf67c7f0b nonce = 48348
================================================================================
The Merkle Tree:
['881f2b580cb3db870f86eebbf67c7f0b', ['50b2fea9c695ad3927c5d1ac9331e963', ['c6308ce9c86597433b32464caadf5ea9', ['c56ac8c18428001ef049ed89bc604294', ['41c7a37357742592479c9aa95248f166', 'b6ea3525b95676f488b8f1c6dff8848d']]]], '461e9d8a9d2021f13e840fbbfee46fd5']
================================================================================
data passed : cabinet meets to balance budget priorities
pk : Curve( 463 -2 2 ); G( 155 452 ); PK( 263 231 ); PKOrder( 149 )
signature : [9, 30]
================================================================================