1 of 21

Account Abstraction

Making accounts smarter

Yoav Weiss

Ethereum Foundation

Dror Tirosh

OpenGSN

Liraz Siri

OpenGSN

2 of 21

What is Account Abstraction

3 of 21

Accounts in Ethereum

Externally Owned Account (EOA) - controlled by an ECDSA key
Smart Contract - controlled by code

Your current wallet is probably an EOA

4 of 21

The limitations of EOAs - key management is hard

Tightly coupled with a single key
Hard to secure - keys get stolen
Hard to recover - keys get lost

5 of 21

The limitations of EOAs - access control

No access control granularity - same for all EOAs
No multisig
No roles
No spending policies

6 of 21

The limitations of EOAs - gas payment

Gas is paid directly by the EOA
Must maintain ETH balance to pay gas
No privacy

7 of 21

The limitations of EOAs - efficiency & usability

No way to batch operations

approve+transferFrom - two transactions

Expensive on-chain reverts

8 of 21

Smart Contract account managed by the user

What is account abstraction?

Flexible key management and recovery
Arbitrary access control mechanisms
Gas payment can be abstracted
Better efficiency and usability
Opportunity to innovate where it matters most: UX

9 of 21

Use cases: recovery

Social recovery
Dead man’s switch

You just lost your key! What if you could call a couple of your friends, or a paid service provider like your lawyer, and replace your wallet’s key?

With AA we can implement this. The wallet can have a multisig recovery function. 3 out of 5 friends could change your key.

What if your friends suck? Maybe you haven’t lost your key but they try to steal your money. Recovery can have a delay. You see (on-chain) that recovery has been initiated. Use your existing key to cancel recovery and kick them out of your wallet!

Most of us are mortals. What if you’re dead or incapacitated? Will your loved ones be able to access your wallet? Why not add a dead man’s switch?

Add a secondary key which only becomes active if you haven’t used your primary one for a year. Keep this key in a sealed envelope. If it’s stolen or lost, no problem. Replace it using the primary key.

10 of 21

Use cases: signature abstraction

Multisig
Per-device keys
BLS aggregation
Quantum resistant signatures

I probably don’t need to explain what a multisig is. 3 out of 5 people needed to access the wallet.

Device keys. What if we don’t use seed phrases at all, and the user never has to see the key? Generate a different key on each device, keep it secure within the device. Most phones and computers have a security chip that can secure a key and sign with it. Forget about securing keys. Just add your devices. Lost a device? Use another device to remove it from your wallet.

New signature schemes like BLS can aggregate signatures. What if your transaction doesn’t need to include a signature on chain because someone trustlessly aggregated it with many other transactions and just one signature? It could make transactions much cheaper, especially on rollups.

Quantum computers are getting more powerful. One day your ECDSA key will no longer be secure against them. Why not replace your signature scheme with something more quantum-resistant?

11 of 21

Use cases: roles & policies

Spending limits

Small payments? Seamless from your wallet.
Sending $1M? Go get your ledger.

Multiple roles, delegating specific actions.

Payroll can pay employees once a month, with a spending limit and a signature from the controller.
Legal can perform on-chain votes with the company’s tokens, but can’t transfer them.
CFO can transfer any sum with 24 hours delay and a signature from another C-level executive.
External auditor monitors delayed payments and can veto them, but can’t initiate transfers.

Session keys

Ephemeral key kept in the browser can perform less-sensitive operations.

Maybe you transact often, but seldom send a million dollars. Why not encode this into your wallet? Set a daily spending limit.

But sometimes you really do want to send a million dollars? No problem. Add another key - a Ledger kept in your safe. Send small amounts seamlessly from your phone, but when you need to send a large amount, go get your ledger.

What if the wallet is your company’s treasury? Add role-based policies.

Payroll can pay employees once a month, with a spending limit and a signature from the controller.
Legal can perform on-chain votes with the company’s tokens, but they can’t transfer them.
The CFO can transfer any amount, but with a 24 hours delay and with an additional signature from another C-level executive.
External auditor monitors delayed payments and can veto them, but can’t initiate transfers.

Session keys. You’re playing a game, you want to use the NFT game objects in your wallets during the game and not have to sign each operation. Add a session key that can only sign messages to the game’s contract, keep it in the browser and let it sign on your behalf. If the browser is hacked it can’t be used to steal your assets, just to perform actions in the game.

12 of 21

Use cases: gas abstraction

Gas sponsorship models
Pay gas with ERC20 tokens
Privacy - interacting with the blockchain without buying ETH
Cross-chain operations

AA enables someone else to pay for the gas.

A game might want to sponsor new users as a growth strategy. Transactions to that game wouldn’t be paid out of the wallet but by the game itself.

Or a wallet developer will charge users by credit card and pay for their gas so they don’t need to go through KYC and buy ETH if they just want to perform non-financial transactions.

Pay with the tokens you hold. If you’re a dog-coin fan, don’t buy ETH. Transact with your dog-coins. A contract can transparently trade it for eth and pay for gas as needed.

Transacting without eth means you don’t have to dox yourself. Withdraw funds from a mixer or a privacy rollup without going through a centralized relay.

Perform operations across multiple chains, pay for the gas on your “home-chain”.

13 of 21

Use cases: batching & automation

Batching and atomicity
Automating time-delayed and event-driven flows

14 of 21

ERC 4337 - why make it a standard?

15 of 21

ERC-4337 - first step toward protocol level Account Abstraction

Shared mempool for arbitrary contract wallets

A single network of bundlers can serve everyone

Make contract-wallets a 1st class citizen

No need to keep an additional EOA funded to use the wallet

Separate validation from execution

Enables efficient block-building and prevents DoS attacks

Efficient batching and aggregation

Makes rollups cheaper

No protocol changes

Start experimenting now on any EVM chain

16 of 21

What’s next?

Enshrine AA into the protocol without enshrining a particular wallet
Seamlessly convert existing EOAs to smart contracts
User can choose the implementation and enjoy new AA features
Default implementation should emulate an EOA

Backward compatible with existing wallets

Can be achieved in a few ways - still in discussion

New transaction type for calling account code - account pays gas
New transaction type just for setting account code
EIP-3074+EIP-5003 (AUTH+AUTHUSURP)
Set default proxy contract for all addresses
…

17 of 21

How do I join the AA revolution?

18 of 21

Build wallets

Start experimenting with ERC-4337
Add useful features like batching and key recovery

Try some ideas from the first part of this presentation

Innovate: build cool new features that were not possible with EOAs
Building a cool ERC-4337 project? Consider applying for an EF grant!

https://esp.ethereum.foundation/

19 of 21

Building a DApp? Consider AA implications

Consider contract wallets a 1st class citizen
Do not assume that accounts can sign messages directly

Use ERC-1271 to check for signatures if the caller has code

Start supporting batching in your UI when connected to a contract wallet that supports it
Consider gas sponsorship models that suit your DApp.

Got a token? Your users could pay gas with it when using your dapp.

Collaborate with wallet devs on ways to improve DApp UX through wallet innovation

20 of 21

Where can I learn more?

21 of 21

Thank you!

Yoav Weiss

Ethereum Foundation

yoav@ethereum.org

@yoavw

Dror Tirosh

OpenGSN

dror@opengsn.org

Liraz Siri

OpenGSN

liraz@opengsn.org

@drortirosh

@lirazsiri