Ethereum at BitGoSecuring and Running A Multisig Ethereum Wallet

Alex Melville

Alex Melville (Technical Lead on the Coins Team)

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github.com/Melvillian

Today’s Plan

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Questions!

BitGo: 2-of-3 Multi-Signature Wallets

No single point of failure!

BITGO KEYCUSTOMER KEY EMERGENCY (BACKUP) KEY

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Supported Coins and Tokens

ETH

ETHEREUM

BTC

BITCOIN

LTC

LITECOIN

BCH

BITCOIN CASH

BTG

BITCOIN GOLD ZCASH

ZEC XRP

XRP

XLM

STELLARDASH

DASH

Augur (REP)

Basic Attention Token (BAT)

Bread (BRD)

Civic (CVC)

Golem (GNT)

Kyber Network (KNC)

Numeraire (NMR)

OmiseGo (OMG)

0x (ZRX)

Maker (MKR)

Worldwide Asset eXchange (WAX)

Zilliqa (ZIL)

iShook (SHK)

Rialto (XRL)

Kin (KIN)

Salt (SALT)Change (CAG)

Power Ledger (POWR)

AppCoins (APPC)

Serenity (SRNT)PlusCoin (PLC)

Linker Coin (LNC)

Snovio (SNOV)

Status Network Token (SNT)

Decision Token (HST) Propy (PRO)

AirSwap (AST)

WaltonChain (WTC)

Storj (STORJ)

SwissBorg (CHSB)

Aragon (ANT)

Aelf (ELF)

Populous (PPT)

OPTin Token (OPT)AION (AION)

Celsius (CEL)

Sentinel Protocol (UPP)

ANA (ANA)

WeTrust (TRST)

Indorse (IND)

Dent (DENT)

Polymath (POLY)

TrueUSD (TUSD)

Bancor (BNT)

Colu Local Network (CLN)

DAOstack (GEN)

Storm (STORM)

Gnosis (GNO)

Pundi X (NPXS)

Gemini Dollar (GUSD)

Paxos (PAX)

Rebglo (REB)

CoinLion (LION)

Hold (HOLD)

Cryptopay (CPAY)

...with more being added all the time.

Ethereum Basics (Addresses vs. Contracts)

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Addresses:

● Basically like Bitcoin Addresses● Single Signature● Initiate Contract Creation/Execution● Pay for Fees! (EIP 101)

Contracts

● Turing-Complete Execution● Extremely Tricky to Reason About

TXCreation

External (Fee) Address

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Ethereum Basics (Two Full Node Implementations)

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Parity Geth

Rust Golang

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The Code:

● Multisignature Wallet● 12 functions

○ Sending○ Safe Mode○ Helper Functions

● Events○ Transacted○ Deposited

● web3.js (we don’t use it!)

Writing and Deploying A Multisig Wallet Smart Contract

Writing and Deploying A Multisig Wallet Smart Contract

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The Deploy:

● Similar Care as Hardware● Audits

○ OpenZeppelin○ Coinspect○ ABDK Consulting

● Fee Address○ It Costs to Deploy Wallet and Receive Addresses

Writing and Deploying A Multisig Wallet Smart Contract

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The Ethereum Multisig Problem: Fungibility and Usability

TX

HitBTC does not see the

transaction!

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The Ethereum Multisig Problem

Multiparty ECDSA Signatures to the Rescue!

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Transaction Nonce Holes: Full Node

1 2 3 4

TX #11 ETH

TX #23 ETH

TX #35 ETH

TX #47 ETH

= Confirmed

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Transaction Nonce Holes: Full Node

1 2 3 4

= DB Query

5

TX #11 ETH

TX #23 ETH

TX #35 ETH

TX #47 ETH

TX #59 ETH

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Full Node

1 2 3 4

5

TX #11 ETH

TX #23 ETH

TX #35 ETH

TX #47 ETH

TX #59 ETH

TX #611 ETH

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Full Node

1 2 3 4

5

TX #11 ETH

TX #23 ETH

TX #35 ETH

TX #47 ETH

TX #59 ETH

TX #611 ETH

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5

DB

5

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5

DB

5

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5 6

DB

6

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5 6

DB

6

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5 6

DB

8

7 8

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5

= DB Query

DB

8

7 8

= Nonce Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5

DB

8

7 8

TX #91 ETH

= DB Query

= Unconfirmed

= Confirmed

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Transaction Nonce Holes: Database

1 2 3 4 5 6

DB

8

7 8

= DB Query

= Unconfirmed

= Confirmed

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Learning to Love/Hate Parity

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Right At Your Fingertips

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Thank You!