Traditional Signers

ERC-4337 accounts can use any authentication logic they want in the signature field of a user operation. However, most of the time a traditional scheme is used.

Authentication on blockchains is traditionally done with private keys. In the Ethereum ecosystem, EIP-1193 signers are used as the common interface. EIP-1193 signers can be injected with a browser wallet (like MetaMask) or with an embedded wallet plugin.

Tool	Key Management Method	Authentication Methods	Plug-n-play front end?
Privy	MPC	Social, device	Yes
Dynamic	MPC	Social, device	Yes
Web3Auth	MPC, key sharding	Social, device, password	Yes
Particle Network	MPC, threshold signature scheme	Email, Social, SMS	Yes
Ethers, viem, web3	Private key	None, often used with MetaMask	No
Magic.link	AWS KMS	Email, Social, SMS	Yes
Lit Protocol	MPC, threshold secret sharing	Custom, provides private-key-pair and Lit Actions framework	No
Fireblocks	Custodial	Custom	No
Turnkey	Custodial	Custom	No

Passkeys & WebAuthn

WebAuthn is a popular authentication framework that leverages authenticators built directly into devices like computers and phones. There are a number of projects developing Passkeys that use WebAuthn for ERC-4337 smart accounts.

Passkeys-4337
Kernel Passkey module (under development)
Barz secp256r1 vaidator in userop.js
Gnosis Safe Example

Session Keys

Session keys can also be used. Typically this requires writing custom code for your smart account or using a smart account library that includes it natively.

Experimental Methods

ERC-4337 allows more than a single private key to validate user operations for an account. This allows you to mix methods for secrets and set security levels for each type of key. We have written about using oAuth and device keys in our blog.