한재선(Jason.han) / Ground X --- Ground X에서 개발하고 있는 퍼블릭 블록체인 플랫폼인 Klaytn에 대해 소개합니다. Klaytn은 대규모 사용자를 기반으로 하는 서비스를 블록체인 기반에서 실행시키는데 최적화된 플랫폼으로서, 기업 수준의 서비스 제공자가 믿고 사용할만한 기능과 거버넌스 등을 제공하는 것을 목표로 한다. 본 발표에서는 현재 블록체인 기술의 이슈를 살펴보고, Klaytn의 솔루션을 소개합니다. 특히 속도와 성능에서의 이슈뿐 아니라 사용자 경험의 개선이나 대규모 서비스를 실행하기 위한 플랫폼 기능들에 대해서도 살펴보고자 합니다.

1. :
) & .
한재선 ( :

3. Distributed Ledger Technology(DLT) +
Distributed Consensus Mechanism +
Distributed Network Technology(P2P) +
Smart Contract & Dapp +
Token Economy Model +
Decentralized Governance Model

4. Data
H( )
Hash Pointer
• A pointer to where data
is stored
• A way to verify that the
data haven’t changed

5. Linked list with hash pointers
prev: H( )
Data
prev: H( )
Data
prev: H( )
Data
Block Hash
point to the previous block
Block #40 Block #41 Block #42
H( )
Head
point to the last block

6. prev: H( )
Data
prev: H( )
Data
prev: H( )
Data
Block #40 Block #41 Block #42
H( )
Head
point to the last block
Can detect the tampering of data
by comparing the next block’s hash value

7. Block Version
Hash of previous block's
header
Merkle Root
Timestamp
nBits (Difficulty Target)
Nonce
02000000
b6ff0b1b1680a2862a30ca44d346d9e8
910d334beb48ca0c0000000000000000
9d10aa52ee949386ca9385695f04ede2
70dda20810decd12bc9b048aaab31471
24d95a54
30c31b18
fe9f0864
Coinbase Transaction
Transaction
Transaction
…
BlockHeaderTransactions
Block Hash
5d7c7ba21cbbcd75
d14800b100252d5b
428e5b1213d27c38
5bc141ca6b47989e
For PoW

8. Merkle Root
https://www.mycryptopedia.com/merkle-tree-merkle-root-explained/

9. If verifying TD, you just need
The merkle root, “HEFGH”, “HAB” and “HC”
Verification runs in time and space
that are logarithmic
in the number of nodes in tree
O(log n)
https://blockonomi.com/merkle-tree/

10. All bitcoin nodes maintain the whole blockchain
Bitcoin
Blockchain
Node #32
Bitcoin
Blockchain
Node #109
Bitcoin
Blockchain
Node #65
Bitcoin
Blockchain
Node #90
Bitcoin
Blockchain
Node #62
Full Nodes
Connect to Bitcoin network and
fully validate transactions and blocks

11. https://bitnodes.earn.com/

12. Bitcoin
Blockchain
Node #32
Bitcoin
Blockchain
Node #109
Bitcoin
Blockchain
Node #65
Bitcoin
Blockchain
Node #90
Bitcoin
Blockchain
Node #62
Mining
Verifying new transactions into a block
by solving hash puzzles (Proof-of-Work)

13. transaction
New transactions are
broadcast to all nodes Bitcoin Network
Block
Collect
new transactions
into a block
Proof-of-Work
Solve hash puzzle
and find a nonce
Broadcast
the block to
all nodes
Verification
Verify PoW
and
transactions
Add
Block
Add the
block to
chain
Block
Node #58 Node #1092

14. Block
Header
nonce
0
1
2
3
…
1312af178c253f84028d480a6adc1e25e81caa44c749ec81976192e2ec934c64
e9afc424b79e4f6ab42d99c81156d3a17228d6e1eef4139be78e948a9332a7d8
ae37343a357a8297591625e7134cbea22f5928be8ca2a32aa475cf05fd4266b7
6e110d98b388e77e9c6f042ac6b497cec46660deef75a55ebc7cfdf65cc0b965
0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9
Assuming the difficulty target is
0001000000000000000000000000000000000000000000000000000000000000
76e4
< the difficulty target
The difficulty target is adjusted every 2016 blocks
to aim for 10 minutes for a block
Find a random number called a nonce,
such that when the block header is hashed along with the nonce,
the result is numerically smaller than the network's difficulty target

15. ) ) ( (
) ( (
Node #32
Node #109
Ethereum
Blockchain
& EVM
Node #65
Node #90
Node #62
smart
contract ABC
smart
contract ABC
smart
contract ABC
smart
contract ABC
smart
contract ABC
Ethereum
Blockchain
& EVM
Ethereum
Blockchain
& EVM
Ethereum
Blockchain
& EVM
Ethereum
Blockchain
& EVM

16. Smart contract example creating a digital token
https://www.ethereum.org/token
Applications that run exactly as programmed without any possibility of
downtime, censorship, fraud or third party interference.
Automating the “if this happens then do that” part of traditional contracts

17. ) ( ( )
Web
Browser
HTML
CSS
Javascript
web3.js
Web Server (nodejs) Ethereum Nodes
Block #2 Block #3 Block #4
Smart
Contract
EVM (Ethereum VM)
Blockchain
Frontend Backend
JSON/RPC
A service that enables direct interaction between end users and providers
(e.g. connecting buyers and sellers in some marketplace, owners and storers in file storage)
Ethereum Dapp consists of a frontend using HTML/Javascript web application and
smart contracts which encode business logic and allow persistent storage.

19. https://www.valuewalk.com/2018/01/transactions-speeds-cryptocurrencies-stack-visa-paypal/

20. /
0
200,000,000
400,000,000
600,000,000
800,000,000
1,000,000,000
1,200,000,000
1,400,000,000
1,600,000,000
Facebook Twitter Ethereum Bitcoin
1.4 billion DAU
150 million DAU
1.4 million tx 425K tx

21. - - . .
Main Chain
SideChain
State Channel
On-Chain (L1)
Off-Chain (L2)
Global Consensus
Local Consensus
Performing some operations “off chain”
Sharding

22. - ()
Root Chain (Ethereum)
Plasma
Chains
Child
Chains
Plasma
Contracts
ü Proposed by Vitalik Buterin and Joseph Poon
(2017)
ü Plasma child blockchains attached to the main
Ethereum blockchain
ü Running independent consensus and handling
most transactions more efficiently
ü Trust and security of plasma chains can be
guaranteed in the main chain(Ethereum) with
plasma contracts and a fraud proof

23. - &

24. 1. Lack of Finality
2. Poor Performance
3. Uncertain Operation Costs
4. Absence of Enterprise Considerations
5. Inconvenient UX

25. 1. Finality
2. High Performance
3. Predictable (or Affordable) Cost
4. Enterprise Readiness
5. User-Friendly UI/UX

26. A new type of blockchain leveraging
private consensus with public auditing
satisfying enterprise demands while
providing user-friendly UI/UX

27. Private consensus with public auditing
= BFT-variant consensus + Open Validation

28. (
CNs form a private network to run a BFT-based consensus algorithm.
Threat model
No more than ⅓ of CNs are dishonest at any moment

29. & )( ( ( & &
Anyone can become an RN to audit and replicate blocks; in return,
RNs get token rewards for their contributions.
All RNs serve client read requests to effectively distribute requests
across the RNs and allow CNs to focus on handling write requests.

30. Klaytn rewards RNs based on the proof of participation.
Proof of Replication
Ensuring a RN stores the whole blocks
Proof of Serving Clients
Ensuring a RN serves read requests of clients
READ (plain) READ (callback)
WRITE

31. Klaytn sharding scheme
Sharding by services which are independent of each other

35. World Population
7.6 Billions
Internet Users
4.2 Billions
54% of population
https://medium.com/@mccannatron/12-graphs-that-show-just-how-early-the-cryptocurrency-market-is-653a4b8b2720
https://www.internetworldstats.com/stats.htm
Crypto Users
20-30 Millions
Less than 1% of Internet Users
Bitcoin Wallet Address: 24M
Ethereum Wallet Address: 31M
Crypto Exchange Users: 20.2M
Those who have crypto wallets
or crypto exchange accounts

36. https://dappradar.com/
https://www.stateofthedapps.com/
2018. 09. 03

37. https://www.stateofthedapps.com/stats
2018. 09. 03

38. Platform Scalability
Easy Crypto UI/UX
Easy Crypto DX(Developer Experience)
Real Value to Non-Crypto Users à Real Use Cases

39. Blockchain Platform
Token
Dapp
smart
contract
ICO(TGE),
IEO,
Airdrop
Token Issuance
Fund by ETH etc
Exchanges
(e.g., Upbit)
Selling
Tokens
Entity
Entity
Purchasing
Tokens
Users
Selling &
Purchasing
Tokens
3) Not trading,
instant exchange
between crypto and
fiat1) New model of
token distribution
2) Seperation between
value and exchange
of token
4) User-friendly
interface

40. /
User Onboarding Experience
• Crypto Wallet
• Private Key Management
• Cryptographic Address
Token Economy Experience
0xde0b295
669a9fd93
d5f28
• Token Price Volatility
• Crypto Exchanges
• Token to Real World
To Attract Non-Crypto Users

41. To Run Enterprise-Level Apps
-

42. / = B =
A = -
= =
= A
/ / =

43. con
contact@groundx.xyz