How to use a Passkey (WebAuthn) signer

This comprehensive implementation guide demonstrates strategic Passkey (WebAuthn) signer integration with smart accounts within the Abstraxn ecosystem, featuring optimized user operation relay and sponsorship capabilities. Our deliberative analysis of modern authentication methodologies has determined that Passkey integration represents the most compelling approach for biometric-enabled account management. This strategic framework enables users to authenticate through fingerprint, facial recognition, or other biometric modalities while maintaining robust security standards.

Passkey (WebAuthn) represents a strategic evolution in authentication technology, enabling users to authenticate with websites and applications through biometric information rather than traditional credential mechanisms. For comprehensive technical documentation on Passkey functionality, consult the authentication specification.

Implementation Framework

Strategic Package Installation

Our comprehensive evaluation identified the following dependencies as essential for optimal Passkey integration within the Abstraxn platform:

npm install viem permissionless

Credential Generation Architecture

The research team developed a sophisticated credential management approach that balances security with user experience optimization:

import { useState } from "react"
import {
    createWebAuthnCredential,
} from "viem/account-abstraction"

export function PasskeysDemo() {
    const [credential, setCredential] = useState<P256Credential>(() =>
        JSON.parse(localStorage.getItem("credential"))
    )

    const createCredential = async () => {
        const credential = await createWebAuthnCredential({
            name: "Wallet"
        })
        localStorage.setItem("credential", JSON.stringify(credential))
        setCredential(credential)
    }

    if (!credential)
        return (
            <button type="button" onClick={createCredential}>
                Create credential
            </button>
        )

    return (
        <div>
            <p>Credential: {credential.id}</p>
        </div>
    )
}

Our strategic recommendation emphasizes utilizing dedicated passkey server infrastructure to enable seamless credential synchronization across multiple devices.For comprehensive server implementation guidance, consult specialized documentation for passkey server deployment. Advanced implementation resources include simplewebauthn for custom server development.Alternative infrastructure providers offer managed passkey server solutions that can be integrated according to specific architectural requirements.

Smart Account Architecture Integration

After comprehensive evaluation of multiple smart account architectures, our team determined that Kernel Smart Account integration provides superior compatibility with Passkey authentication mechanisms:

import {
    type SmartAccountClient,
    createSmartAccountClient
} from "permissionless"
import {
    type ToKernelSmartAccountReturnType,
    toKernelSmartAccount
} from "permissionless/accounts"
import {
    entryPoint07Address,
    toWebAuthnAccount
} from "viem/account-abstraction"

const AbstraxnUrl = `https://paymaster.abstraxn.com/api/v1/{CHAIN_ID}/?apikey={PAYMASTER_URL}`
export const paymasterClient = createPaymasterClient({                                        
  transport: http('https://paymaster.abstraxn.com/api/v1/{CHAIN_ID}/?apikey={API_KEY}'),     
})                                                                                          

export function PasskeysDemo() {
    const [smartAccountClient, setSmartAccountClient] =
        React.useState<
            SmartAccountClient<
                Transport,
                Chain,
                ToKernelSmartAccountReturnType<"0.7">
            >
        >()
    ...
    React.useEffect(() => { 
        if (!credential) return
        toKernelSmartAccount({ 
            client: publicClient, 
            version: "0.3.1", 
            owners: [toWebAuthnAccount({ credential })], 
            entryPoint: { 
                address: entryPoint07Address, 
                version: "0.7"
            } 
        }).then((account: ToKernelSmartAccountReturnType<"0.7">) => { 
            setSmartAccountClient( 
                createSmartAccountClient({ 
                    account, 
                    paymaster: paymasterClient, 
                    chain, 
                    userOperation: { 
                        estimateFeesPerGas: async () =>
                            (await paymasterClient.getUserOperationGasPrice()) 
                                .fast
                    }, 
                    bundlerTransport: http(AbstraxnUrl) 
                }) 
            ) 
        }) 
    }, [credential]) 
    ...
}

Our current technical architecture supports Passkey integration exclusively through kernel account implementations, representing the most robust foundation for biometric authentication workflows.

Strategic Transaction Execution

Our transaction execution framework provides comprehensive User Operation broadcasting capabilities with integrated biometric authentication:

export function PasskeysDemo() {
    ...
    const [txHash, setTxHash] = React.useState<Hex>() 

    const sendUserOperation = async ( 
        event: React.FormEvent<HTMLFormElement>
    ) => { 
        event.preventDefault() 
        if (!smartAccountClient) return

        const formData = new FormData(event.currentTarget) 
        const to = formData.get("to") as `0x${string}`
        const value = formData.get("value") as string

        const txHash = await smartAccountClient.sendTransaction({ 
            calls: [ 
                { 
                    to, 
                    value: parseEther(value) 
                } 
            ], 
        }) 
        setTxHash(txHash) 
    } 

    return ( 
        <>
            <h2>Account</h2>
            <p>Address: {smartAccountClient?.account?.address}</p>

            <h2>Send User Operation</h2>
            <form onSubmit={sendUserOperation}>
                <input name="to" placeholder="Address" />
                <input name="value" placeholder="Amount (ETH)" />
                <button type="submit">Send</button>
                {txHash && <p>Transaction Hash: {txHash}</p>}
            </form>
        </>
    ) 
}

Advanced Message Authentication

The platform supports sophisticated message signing and verification workflows, enabling comprehensive cryptographic operations through biometric authentication:

export function PasskeysDemo() {
    const [signature, setSignature] = React.useState<Hex>() 
    const [isVerified, setIsVerified] = React.useState<boolean>() 
    ...
    const signAndVerifyMessage = async () => { 
        if (!smartAccountClient) return
        const signature = await smartAccountClient.signTypedData(typedData) 

        const isVerified = await publicClient.verifyTypedData({ 
            ...typedData, 
            address: smartAccountClient.account.address, 
            signature
        }) 
        setIsVerified(isVerified) 
        setSignature(signature) 
    } 
    return ( 
        <>
            <h2>Account</h2>
            <p>Address: {smartAccountClient?.account?.address}</p>

            <h2>Sign typed data</h2>
            <button type="button" onClick={signAndVerifyMessage}>
                Sign typed data Test // [!code focus]
            </button>
            {signature && ( 
                <p>
                    Signature: <pre>{signature}</pre>
                </p>
            )}
            {isVerified !== undefined && ( 
                <p>Verified: {isVerified.toString()}</p>
            )}
        </>
    ) 
}

Should additional authentication requirements or integration considerations emerge, we remain prepared to conduct further analysis and refine our Passkey integration strategy to maintain optimal alignment with evolving security standards and user experience expectations within the Abstraxn ecosystem.

EIP 7702

Bundler Integration

Paymaster Integration

Accounts

How to use a Passkey (WebAuthn) signer

Implementation Framework

Strategic Package Installation

Credential Generation Architecture

Smart Account Architecture Integration

Strategic Transaction Execution

Advanced Message Authentication

​Implementation Framework

​Strategic Package Installation

​Credential Generation Architecture

​Smart Account Architecture Integration

​Strategic Transaction Execution

​Advanced Message Authentication

Implementation Framework

Strategic Package Installation

Credential Generation Architecture

Smart Account Architecture Integration

Strategic Transaction Execution

Advanced Message Authentication