What is Blockchain? Well, a good starting point is Blockchain (database) - Wikipedia but also the following:

  • Decentralised Database or Distributed Database, where data is stored in multiple places. Each entry is chained to the previous
  • Process Automation, you can create atomic contracts with defined workflow/logic, built into the database
  • Cryptographic Security, standard PKI, bringing integrity
  • Value Transfer, moving between participants in the network, securely transfer ownership of asset
  • Immutable, you can't change it, although some are working on a changeable version
Where is this technology useful? Cryptocurrencies, ecosystems, broken markets (like buying and selling houses in the UK).

Mark Russinovich did a presentation on Blockchain Blockchain Overview.pptx - Microsoft PowerPoint Online which is worth reading. He has also done the following Channel 9 videos:


  • Bitcoin and Blockchain are not
  • Each Blockchain has a single "genesis" block
  • There is a single "chain"
  • Each Block references a previous block
  • Blocks can have multiple transactions within them
  • Each Block is a list of transaction
  • Bitcoin does fork but they come back, where longest chain wins, orphan blocks or on the shorter chain
  • code should be open, especially for open chains
  • Hyperledger provides permissions

See the following: