Blockchain is the “new new” database and much more, i.e., it is a decentralized distributed ledger administered by a peer-to-peer network collaborating on a common consensus protocol for communication and validation of new blocks of data. Top that off with “smart contracts” i.e., programs which deploy to the block-chain network and are invoked to execute transactions. To make that happen the blockchain is a confluence of existing technologies including distributed database, public-key encryption, hashing and consensus protocols. It is a dramatic improvement in the landscape of information collection, distribution, and governance. That said, blockchain is over a decade old and still needs maturing. In this and the chapters to follow we will introduce concepts needed to understand the blockchain technology, as well as the tools used to write “smart contracts,” build and deploy distributed applications that interact with AI and IoT.

The cryptocurrency Bitcoin, originally introduced by mythical Satoshi Nakamoto, see,https://bitcoin.org/bitcoin.pdf, in 2008 heralded the advent of the blockchain. Blockchains allow for a new distributed software and data architecture. It provides for networks of untrusted participants with the ability to establish agreements, i.e., “smart contracts” using decentralized and transactional data in a secure way and without requiring a central point of control and supervision. Public blockchains ensure trust among anonymous counterparts in decentralized systems without the need of a central authority to verify the validity of the transactions in the ledger. See,figure 2-1.

The blockchain data typically transactional is stored in blocks that cannot be altered retroactively without alteration of all subsequent blocks. The blockchain is programmable and facilitates the so called “smart contracts” which are intended to digitally execute and enforce the performance of a contract. Smart contracts allow the performance of credible transactions without third parties. These transactions are trackable and irreversible.