The document discusses Ethereum 2.0's deposit contract and proof of stake system. It explains that the deposit contract allows users to stake Ethereum in the current proof of work chain to validate transactions in the upcoming proof of stake system. The deposit is stored using a Merkle tree to efficiently store over 4 billion deposit records. The document also provides sample Solidity code to demonstrate depositing and withdrawing ERC-20 tokens by calling the smart contract, and discusses using this method to manage blockchain assets. It describes an identification project called ACHER that uses smart contracts for deposit and withdrawal of various asset types.

1. SCVSoft : Benajmin Hyokeun Oh
주식회사 에스씨브이소프트
Ethereum 2.0
And Deposit Contract

2. Whoami
Benjamin Hyokeun Oh (오효근)
CEO of SCVSoft
• Hanyang Univ. majoring CSE
• Best of the Best 4th,
Vulnerability Research Track
• CodeEngn Conference 12
(2015)
• Inc0gnito 2015/2016 Speaker
• (주)Doobit ex-CDO For more info : www.benjioh5.com
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3. - NOT the Space Contruct Vehicle!
- Security & Cryptocurrency Venture
- B2B w/ R&D, auditing, consulting based company
- first B2C product (ACHER) will be lauching at 2019 Q4 or 2020 Q1
For more info : www.scvsoft.net
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SCVSoft

4. - No one in Korea talks about deposit phase's importance (Really?)
- There are lots of description about FFG, CBC, Chasper, and Beacon Chain.
BUT there are few article on deposit contract.
- Want to say there are extensible way to ERC-20 deposit/withdrawal activity.
- ACHER -our first B2C project- has deposit/withdrawal action on smart contract by Call
and DelegateCall. I can be adopted every another new contract!
Why I choose deposit contract?
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5. - Ethereum 2.0 has 3 Phases for PoW to fully PoS support (or more phases?)
- Each phase, Beacon Chain and shards get more feature of ETH 1.0 Chain.
- Then Why PoS is needed for Ethereum 2.0?
- More fast and decentralized chain will be made
- More power efficient to make system working than PoW
Eth2.0 & Pos & Deposit &…
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6. - Then, What is Proof of Staking?
- Kind of betting or deposit for making new block.
- Who use PoS?
- QTUM, EOS, and so on...
- Any difference btw ordinary PoS?
- FFG is totally different from other PoS Algorithm.
Eth2.0 & Pos & Deposit &…
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7. - Then how to stake Ethereum in Eth1.0 Chain?
- Using deposit contract. Send adjust amount Ethereum to deposit contract.
- How to withdraw it?
- There are no way until Phase 2. Sending Ethereum to deposit contract is one way trip.
- All Ethereum send to deposit contract is only usable on Beacon chain. There is no
turning back.
- Q : Is it a risk factor? A : Maybe
Eth2.0 & Pos & Deposit &…
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8. - Then how to stake Ethereum in Eth1.0 Chain?
- Using deposit contract. Send adjust amount Ethereum to deposit contract.
- How to withdraw it?
- There are no way until Phase 2. Sending Ethereum to deposit contract is one way trip.
- All Ethereum send to deposit contract is only usable on Beacon chain. There is no
turning back.
- Q : Is it a risk factor? A : Maybe
Eth2.0 & Pos & Deposit &…
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9. - Made by Vyper
- Using @Payable decorator to deposit Ethereum
- Using Merkle Tree to store data ( > 4.2 Billion deposit data)
- About 110 line of vyper code makes fully deposit contract for the beacon chain
Deposit contract
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10. - Made by Vyper
- Using @Payable decorator to deposit Ethereum
- Using Merkle Tree to store data ( > 4.2 Billion deposit data)
- About 110 line of vyper code makes fully deposit contract for the beacon chain
Deposit contract
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11. - Made by Vyper
- Using @Payable decorator to deposit Ethereum
- Using Merkle Tree to store data ( > 4.2 Billion deposit data)
- About 110 line of vyper code makes fully deposit contract for the beacon chain
Deposit contract
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12. - Made by Vyper
- Using @Payable decorator to deposit Ethereum
- Using Merkle Tree to store data ( > 4.2 Billion deposit data)
- About 110 line of vyper code makes fully deposit contract for the beacon chain
Deposit contract
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13. - Made by Vyper
- Using @Payable decorator to deposit Ethereum
- Using Merkle Tree to store data ( > 4.2 Billion deposit data)
- About 110 line of vyper code makes fully deposit contract for the beacon chain
Deposit contract
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14. - It takes too long time to describe it. I'll say very little of it.
- It's data structure which can extend data with very low cost and lower time.
- Lots of bit operations and hashing is main thing of merkle tree.
- 32 depth == 2^32 depositable address == 4,294,967,295 Address!
- 2^(32-1) == 2,147,483,648 Address!
- Then 2^32 * 192 Byte == 824,633,720,832 Byte???
- > 824GB ??
Merkle tree in deposit contract
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15. - No!
- (2^32 + 2^31 + 2^30 + ... + 2^1 + 2^0) * 32 Byte (SHA256) == 274,877,906,912 Byte
- < 275 GB (...?) for 4,294,967,295 Address!
- Well.... It's efficient than old one.... Hmm...
- Merkle Tree grows when new data is added. So, must has lesser size than 275GB
- (2^([log_2(n)]+1) - 1) * 32 Byte < 32 * n Byte will be size of merkle tree.
Merkle tree in deposit contract
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16. - There are more efficient way to do it. isn't it?
- Yes. Let's see the code.
Merkle tree in deposit contract
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17. - There are more efficient way to do it. isn't it?
- Yes. Let's see the code.
Merkle tree in deposit contract
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18. Only the Ethereum is
depositable?

19. No!

20. Sample Solidity
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21. Sample Solidity
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22. Sample Solidity
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23. Sample Solidity
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24. Sample Solidity
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25. Done?

26. No!

27. Sample Solidity w/ SCVToken
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28. Sample Solidity w/ SCVToken
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29. Sample Solidity w/ SCVToken
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30. Sample Solidity w/ SCVToken
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31. Token can be send to the smartcontract
(actually ERC20 smart contract's data is updated,
and doesn't care about address type)
Sample Solidity w/ SCVToken
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32. Sample Solidity w/ SCVToken
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33. Let's Init SCVToken addr
Sample Solidity w/ SCVToken
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34. Sample Solidity w/ SCVToken
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35. Initialized!
Sample Solidity w/ SCVToken
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36. Now using Smartcontract's call (or delegatecall) send some ERC20 Token
Sample Solidity w/ SCVToken
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37. Now using Smartcontract's call (or delegatecall) send some ERC20 Token
Sample Solidity w/ SCVToken
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38. <- Don't forget * 10^18 (decimal) call! I forgot about that :(
<- Target Addr
Sample Solidity w/ SCVToken
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39. Sample Solidity w/ SCVToken
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40. calls smartcontract
Sample Solidity w/ SCVToken
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41. - ㅊㅊㅊㅊㅊ차ㅗㅕ추ㅗㅕㅜㅠㅆㄹㅅ총여ㅜㅜㅎ퍄차아ㅣㄱ도셔ㅣㅕ핓
-
It works! Smart contract send token to another address!
Sample Solidity w/ SCVToken
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42. - Using call and delegatecall, there are way to DEPOSIT & WITHDRAW ERC20 Tokens.
- Actually, ERC721, ERC1155 would works too.
- So, We can construct one way trip to another chain or smart contract based asset
management!
- But If ERC20 Contract has function which force A to B transfer by admin, there are some
problem on deposit or staking. :(
- Actually, Ethereum transfer and ERC20 transfer can be never same thing.
- But there are way to mock staking and desposit system.
Sample Solidity w/ SCVToken
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43. - No one in Korea talks about deposit phase's importance (Really?)
- There are lots of description about FFG, CBC, Chasper, and Beacon Chain.
BUT there are few article on deposit contract.
- Want to say there are extensible way to ERC-20 deposit/withdrawal activity.
- ACHER -our first B2C project- has deposit/withdrawal action on smart contract by Call
and DelegateCall. I can be adopted every another new contract!
Sample Solidity w/ SCVToken
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44. - No one in Korea talks about deposit phase's importance (Really?)
- There are lots of description about FFG, CBC, Chasper, and Beacon Chain
BUT there are few article on deposit contract.
- Want to say there are extensible way to ERC-20 deposit/withdrawal activity.
- ACHER -our first B2C project- has deposit/withdrawal action on smart contract by
Call and DelegateCall. It can be adopted every another new contract!
Sample Solidity w/ SCVToken
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45. Identification on Blockchain

46. - ACHER -our first B2C project- has deposit/withdrawal action on smart contract by
Call and DelegateCall. It can be adopted every another new contract!
- Identification through smart contract which is called ERC-725 is used for DID and multi
support of EOA.
- Present day, Our Goal is using smart contract for Deposit and Withdrawal of any type of
asset in Blockchain.
- Using Depositable smart contract, BLOCKCHAIN WOULD BE MORE EASIER
ACHER
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47. ACHER : Identification on blockchain
User
Signature Checking
& Authorization
Get Authority Info
Private Key
KYC
Digital Signature
Identification
Crypto Wallet
OAuth2
FIDO2
END Service
ERC-725
ERC-1484
Smart Contract
Service Blockchain Stack
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48. KYC
Digital Signature
Identification
Crypto Wallet
OAuth2
FIDO2
END Service
Browser Extension
(e.g. Metamask)
iOS
Android App
Dapp
(Centralized)
Auth Server
IPFS/
Swarm
decentralize
SDK (js/python)
Service Blockchain Stack
ERC-725
ERC-1484
Smart Contract
ACHER : Identification on blockchain
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49. KYC
Digital Signature
Identification
Crypto Wallet
OAuth2
FIDO2
END Service
Browser Extension
(e.g. Metamask)
iOS
Android App
Dapp
(Centralized)
Auth Server
IPFS/
Swarm
Service Blockchain Stack
ERC-725
ERC-1484
Smart Contract
B2B Part
ACHER : Identification on blockchain
decentralize
SDK (js/python)
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50. KYC
Digital Signature
Identification
Crypto Wallet
OAuth2
FIDO2
END Service
Browser Extension
(e.g. Metamask)
iOS
Android App
Dapp
IPFS/
Swarm
Service Blockchain Stack
ERC-725
ERC-1484
Smart Contract
B2C Part
ACHER : Identification on blockchain
decentralize
SDK (js/python)
(Centralized)
Auth Server
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51. FIN