Currency and Blockchain
What's Currency
Currency
Store of value
Unit of account
Exchangable
Now
Issued by authority
NTD
USD
Gash Point
How to issue a currency
Trust
Fluidity
Trust
Decentralize
Encryption Algorithm
Asymmetric cryptography
Hash Function
How to
whisper
Alice Public Key
Bob
Alice
Give me money
Alice Private Key
Encrypt
Decrypt
Problem?
Verification
Double Spent
Resolution
Post 1 dollar to Alice
Bob Private Key
Bob
Alice
Post 1 dollar to Alice
Bob Public Key
Signification
Verification
Katze
👀
Verification
But Signed message is copyable
Resolution
Post 1 dollar to alice
Transection
Serial
1503
Post 15 dollar to alice
Transection
Serial
1504
From
Bob
From
Bob
But serial is predictable or collision.
Resolution
Post 1 dollar to alice
Transection
Last ID
1f3180a08c80d890f
Post 15 dollar to alice
Transection
Last ID
From
Bob
From
Bob
07215709b70d770c
Hashed
Root Block
Blockchain
Ledger
But this hash too easy
Blockchain
Parent Block
Child Block
Child Block
Child Block
Determine who can write ledger
Resolution
Post 1 dollar to alice
Transection
Last ID
000000a08c80d890f
From
Bob
Nonce
X = ?
Block Hash
X = 1
b9af8ea08c80d890f
X = 2
b8a80b80c9d8e8f0a
X = 3
0a7b879c78978d79f
X = 8692
0000009c78978d79f
Proof of work
Why should user work?
Resolver Earning
Transection Fee
Ledger Writer Reward
Because block size is limited
Reduce by chain long
Dilemma
Mining Cost
Transection Rate
Transection Cost
Proof of Stake
Delegate Proof of Stake
PBFT
Future
Ethereum
Smart Contract
Private Chain