Explaining Blockchain to your Mom

 Let’s go back a hundred years and visit a small village in India. The village is celebrating the birth of a girl, Maya. Maya’s parents, Arun Joshi and Mira Joshi have invited the entire village for the naming ceremony. The girl’s grandmother wraps the girl in beautiful new clothes and blankets that she has made. The women assemble in the middle and ask the aunt to name the child. The ceremony calls for the aunt to whisper the name in the child’s ear and then announce it to everyone assembled. The aunt proudly names the child Maya. The villagers feast on specially prepared food and bless the child.

The girl will now be known as Maya Arun Joshi; her first name followed by her father’s name and ending with her family name. As Maya grows up, she will use her full name to introduce herself to people she meets for the first time. People may not know her, but they will certainly know her father, Arun or at least her family, Joshi. 

           At a suitable age, Maya gets married to Nilesh Vijay Sharma. As you would guess, the entire village is invited for the wedding. After the wedding ceremony, the couple is introduced to the entire village. Maya’s name changes to Maya Nilesh Sharma. She takes on her husband’s name as her middle name and her husband family name. 

           Now, the village doesn’t have either birth registration system or marriage registration system. But the entire village knows who Maya is by her full name (both before and after marriage). 

           This simple story explains the core Blockchain concepts of 

           1. State Machine

           2. Open Distributed Ledger

           3. Immutable records

           4. Decentralized Trust

Before Maya was born, the village in terms of its residents was in a stable State. In this village there is no birth or marriage registry for maintaining records. A Blockchain system also seeks to do away with institutions such as Central Clearing House/Intermediaries fulfilling a similar purpose. Blockchains are used to record transactions between multiple parties without having the need for a central trustworthy authority keeping record.

The Blockchain Ledger holds the list of all blocks chained together, which are records of the transactions. This can be compared to the chronological record of births, deaths, marriages in our village analogy saved by the name of the father/husband/family. This ledger must be Open, Distributed and Public. This is ensured by keeping copies of the ledger on several nodes which are like servers that are accessible publically on the Internet. In our analogy, the function of nodes is fulfilled by the villagers who know everyone else in the village and at least one or two of their previous generations. This is the Public, Distributed Ledger that everyone has a copy of.

The Trust (Authentication) is Decentralized. Such a ledger is immutable (cannot be modified/updated/defrauded) as, each node needs to be simultaneously attacked and corrupted in order to corrupt the ledger, otherwise the discrepancies between nodes will be discovered. The Transition of the State during the addition of a record to the ledger follows pre-defined rules everyone agrees to. In Maya’s case, her birth and wedding are records added to the ledger through well-defined and accepted ceremonies attended by all villagers. If such a ceremony is avoided, then Maya’s updated status will fail to be recorded by every villager. In a lighter vein, this can often lead to gossip!

The naming or the wedding ceremony are the well-defined and agreed upon processes to add Blocks to the Blockchain modifying the State. The reason for inviting guests in naming and wedding ceremonies is to have the majority of the villagers (Nodes) in the decentralized network validate and approve the new block. 

           This collective knowledge is basically the Blockchain of identities in this village. This is an attempt to explain Blockchain in the simplest of terms. Any analogy will have some fitment issues. Comments, suggestions, appreciations, bricks... ??