A basic overview of what blockchain is with step-by-step easy to follow explanation of its core concepts. It should be easy for anyone with zero knowledge of blockchain to follow through the slides
2. Myth-Busters
● Blockchain doesn’t mean crypto-currency
● Crypto-currency doesn’t mean BitCoin or Ethereum
--------------------------------
● Blockchain is just a technology. ex: database | cache | etc
● Crypto-currency uses an implementation of blockchains
● BitCoin, Ethereum these are all different kinds of
crypto-currencies which use different ways of
implementing the Blockchain
5. What is a hash?
A scrambled representation of a value which is hard to
reverse to determine the original value that it represents.
h = f(x)
Popular hashing functions:
sha1 | sha256 | md5 | AES | bcrypt | many more
10. It always starts with
a block
-
the GENESIS block
● index = 0
● no previous hash
11. The Data
The data can be any
data representing
any event or any
information that
happened in the
world
12. the hash is
produced by
hashing the data
and the nonce
hash = f(data+nonce)
The Hash
Disclaimer: The hash is actually computed from a
combination of several fields like:
(data + nonce + index + previous hash + timestamp).
But for the simplicity of these slides, we will only consider
(data + nonce).
13. The nonce is
determined by
the miner ,
incrementally until
the hash meets a
pre-defined.
difficulty level .
The Nonce
15. ● the data contains any new
information / event
● increments the index by 1
● determines a new nonce
to validate a new hash for
the new data
● previous hash refers to
the hash of the previous
block - which 1 index less
Enter next block
16.
17. ● There is one genesis block
● Every other block follows the genesis block sequentially
● Every block knows the hash of its previous block
● Modify the data in one block:
○ it changes its own hash
○ which invalidates the value of ‘previous hash’ in the
next block
○ which invalidates the next block’s own hash
○ the whole chain collapses following that one block
One chain of many blocks
20. Some pointers
An immutable record of the past
Historical events cannot be changed easily
Democratically determine problematic peers
Can use public-private keypair-signing to further
reinforce integrity of the blockchain