How to Build a “Passkey‑First” Wallet Experience

Building a wallet experience that prioritizes passkeys can be a game changer for your users' security and convenience. Let’s dive into how you can create a wallet that puts passkeys front and center.

What Are Passkeys?

Passkeys are a modern alternative to traditional passwords, making it easier and safer for users to access their accounts. Instead of remembering complex passwords, users can authenticate using cryptographic keys linked to their devices.

Here’s why they’re awesome:

• More Secure: Harder to steal than passwords.
• User-Friendly: No more password resets or forgotten logins!
• Phishing Resistant: They can’t be phished like regular passwords.

Steps to Build Your Passkey-First Wallet

1. Understand the User Journey

Before you even think about building, get into the heads of your users. What do they need? What would make their experience smoother?

2. Integrate Passkey Authentication

Make it super simple for users to authenticate with their passkeys. Here’s how:

• Enable FIDO2 and WebAuthn: These protocols support passkey logins and are widely accepted.
• Offer Multiple Options: Allow users to pick their preferred method, like biometrics or security keys.

3. Design the Wallet UI/UX

Keep the design clean and intuitive. Here are some design tips:

• Simple Navigation: Users should easily find what they're looking for.
• Quick Access to Key Features: Make their most-used features front and center.

4. Focus on User Education

Even though passkeys are simpler, some users might still be confused. Provide clear and friendly guidance like:

• Onboarding Tutorials: A little guidance goes a long way.
• FAQs: Help users understand passkeys and how they work.

5. Test, Iterate, and Gather Feedback

No matter how great you think your wallet is, it needs real-world testing. Encourage users to share their thoughts, and don’t shy away from making changes based on their feedback.

6. Promote a Secure Environment

Security is key, literally! Emphasize how passkeys enhance security by educating users. Use messaging that reassures them that their data is safe and sound.

Conclusion

Creating a “passkey-first” wallet experience is all about prioritizing user convenience and security. By understanding your users, seamlessly integrating passkey authentication, and focusing on design and education, you’ll build a wallet that your users will love.

For more information on implementing passkeys, check out the FIDO Alliance and WebAuthn Specifications. Happy building!

• It turns out your “Connect wallet” funnel is losing about 30-60% of users before they even make their first onchain move. Why? Because things like extensions, seed phrases, and OTPs just add a bunch of annoying friction at the worst possible moment.
• Meanwhile, the engineering team is suggesting, “Let's just add passkeys!” Procurement is busy wanting those NIST mappings, and the chain teams are scratching their heads, wondering how to verify secp256r1 signatures onchain without racking up 200k+ gas fees or relying on flaky relays.
• And don’t even get me started on mobile parity--it’s a complete mess! Android’s Credential Manager, Apple’s AuthenticationServices, and Windows Hello/Edge sync just don’t play nicely together across different devices. Plus, AAGUID allowlists and attestation are not set up right, which means security can’t give the thumbs up. (developers.google.com)
• Missed launch dates: It's all too common for backend teams to underestimate the nitty-gritty of WebAuthn--like origin/RPID binding, clientDataJSON hashing, and attestation policy. This often leads to some last-minute rollbacks. Check out the details here.
• Support blow-ups: If cross-device syncing isn't handled well (think using non-syncable providers), users can get stranded. There’s a reason why help centers give specific warnings against certain setups! For more info, head over to Coinbase's help page.
• Onchain dead ends: If you're missing native P-256 verification, you might end up either shelling out a ton of gas with big-int libraries or resorting to centralized relays that your auditors are definitely going to flag. EVM chains that added P-256 at a precompile address got around this issue. Check it out here.
• Compliance stalls: You can't claim to have "phishing-resistant MFA" or align with AAL2/AAL3 if your passkey strategy, attestation enforcement, and device-binding policy aren't crystal clear. NIST's guidance for 2024-2026 really emphasizes this point. Read more about it here.

We create wallets that are fully equipped with passkey features, enabling them to convert, verify on-chain, and comply with enterprise procurement standards. Here’s what drives us:

1) Treat passkeys as production auth, not a feature

• Make sure to tie them to your product’s registrable domain suffix as the RPID. It’s super important to enforce strict origin checks on the server side so you don't end up with the “it works on localhost only” issue. Check out the details on w3.org.
• Stick with the platform’s native user experience:
  • Android: Use the Credential Manager (API level ≥28) for a seamless bottom sheet experience and conditional UI. This approach cuts down on confusion and brings passkeys, federated logins, and passwords together under one API. More info at developer.android.com.
  • iOS/macOS: Utilize the AuthenticationServices passkey flows. This lets you support AutoFill-assisted logins and give users easy paths for resetting their passkeys. Plus, Chrome on macOS now works with iCloud Keychain, so that’s a win! Dive deeper at developer.apple.com.
  • Windows 11: Edge is now capable of syncing passkeys across devices. Don't forget to create a clear policy for managing enterprise fleets versus personal devices. You can read more about it on windowscentral.com.

Make Verification On-Chain Cheap and Standard

• On the Ethereum mainnet, thanks to the Fusaka hard fork happening on December 3, 2025, EIP‑7951 introduced a native secp256r1 (P‑256) precompile at address 0x100. The cost for verification? A neat 6,900 gas--so no need to fuss over custom bigint libraries anymore! On OP‑Stack chains, they rolled out P256VERIFY even earlier during the Fjord upgrade, also at address 0x…0100 through RIP‑7212. So, let’s design for both! Check out more details here.

Solidity example: verifying a WebAuthn assertion

When working with WebAuthn, it’s essential to verify the assertions to ensure your application is secure. Below, we’ll walk through a simplified example of how to verify a WebAuthn assertion within a Solidity smart contract.

Step 1: Collect the necessary data

Before you jump into the verification process, make sure you have the following data from the client:

• Client Data JSON: This is the data sent by the client.
• Authenticator Data: A byte string that contains information related to the authentication event.
• Signature: The signed data from the authenticator.
• Public Key: The public key associated with the user’s credential.

Step 2: Solidity smart contract setup

Here’s a basic outline of your Solidity smart contract that will handle the verification:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract WebAuthnVerifier {
    // Mapping to store public keys
    mapping(address => bytes) public publicKeys;

    // Event that emits verification result
    event VerificationResult(address indexed user, bool success);

    // Store public key for user
    function setPublicKey(bytes memory _publicKey) public {
        publicKeys[msg.sender] = _publicKey;
    }

    // Verify assertion
    function verifyAssertion(
        bytes memory clientData,
        bytes memory authenticatorData,
        bytes memory signature
    ) public {
        // Here, add your verification logic!
        // You’d typically decode and verify the values

        bool isValid = validateSignature(clientData, authenticatorData, signature);
        emit VerificationResult(msg.sender, isValid);
    }

    // Dummy signature validation function
    function validateSignature(
        bytes memory clientData,
        bytes memory authenticatorData,
        bytes memory signature
    ) internal view returns (bool) {
        // Logic for signature validation goes here
        // For now, just return true for simplicity
        return true;
    }
}

Step 3: Explanation of the code

• setPublicKey: This function allows users to store their public keys in the contract. It’s essential for verifying the assertions later on.
• verifyAssertion: This is where the magic happens. You take in the client data, the authenticator data, and the signature to verify if the user's credentials match.
• validateSignature: This is a placeholder function. In a real-world application, you should implement the logic to properly validate the signature against the public key.

Step 4: Testing the contract

To test your smart contract, you'll want to deploy it using tools like Remix or Truffle. Make sure to call the functions with the appropriate data to see if everything’s working as it should!

Conclusion

Verifying a WebAuthn assertion in a Solidity contract might seem complex at first, but with the right setup, you can ensure your app remains secure. Experiment with this example and expand upon it to suit your needs. Happy coding!

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

// Inputs:
//  - h: keccak256(message) where message = authenticatorData || sha256(clientDataJSON)
//  - r,s: ECDSA(P-256) signature
//  - qx,qy: uncompressed P-256 pubkey coordinates (from COSE_Key at registration)
//
// Precompile address:
//  - Ethereum L1 (EIP-7951): 0x0000000000000000000000000000000000000100 (0x100)
//  - Some L2s (RIP-7212/OP-Stack): same address (0x...0100)
library P256Verify {
    address constant P256PRECOMPILE = address(uint160(0x100));

    function verify(bytes32 h, bytes32 r, bytes32 s, bytes32 qx, bytes32 qy)
        internal view returns (bool ok)
    {
        bytes memory input = abi.encodePacked(h, r, s, qx, qy);
        uint256[1] memory out;
        assembly {
            let inPtr := add(input, 0x20)
            // staticcall(gas, to, inOffset, inSize, outOffset, outSize)
            if iszero(staticcall(gas(), P256PRECOMPILE, inPtr, 160, out, 32)) { ok := 0 }
            // precompile returns 32-byte 0x1 on success, empty on failure
            if eq(mload(out), 1) { ok := 1 }
        }
    }
}

Hashing the WebAuthn assertion the right way:

• First, create the message by combining authenticatorData with SHA‑256(clientDataJSON).
• Then, compute h using SHA‑256(message).
• Don’t forget to parse the COSE_Key (alg −7, crv P‑256) to extract qx and qy. (developers.yubico.com)

3) Build the Wallet with Account Abstraction in Mind

• Let’s start with ERC‑4337 smart accounts. They come with this nifty “passkey validator” module that checks P‑256 signatures using the precompile in validateUserOp(). If you’re on a chain that doesn’t have this precompile, no worries--just switch to a trusted library or connect to a chain that's got RIP‑7212. You can dive into the details here.
• Moving on to EIP‑7702 (Pectra, May 7, 2025), this update allows externally owned accounts (EOAs) to temporarily hand over execution to contract logic. This is awesome because it means you can offer a “same address” user experience right alongside those 4337 accounts, all powered by passkeys. Check it out here.
• And don’t forget about session keys! They're a game changer for wallet-managed sessions, making those “one-tap” in-app actions a reality. Just set your parameters by time, target, and spending limits. Plus, you should align with the new modules like ERC‑6900/7579 and make sure to document those scopes in the user interface. If you want to read more about it, head over to this link.

4) Platform-Grade Security Controls for Procurement Approval

• Attestation and AAGUID Allowlisting: Make it mandatory to have attestation during registration to control which authenticators can sign up. You'll want to check certification chains against the FIDO Metadata Service (v3.1) and enforce hardware-backed storage when necessary. Keep a well-maintained AAGUID allowlist specific to each environment.
• NIST AAL Mapping:
  • For syncable/cloud passkeys, aim for AAL2. This means they should be phishing-resistant and function as a two-factor equivalent with a combination of device and biometric/PIN.
  • When dealing with device-bound passkeys (like TPM, Secure Enclave, or YubiKey), you'd be looking at AAL3. This provides strong resistance against verifier impersonation and ensures the key isn't exportable. Make sure this info is documented in your RFP or Security Annex. (fidoalliance.org)
• Logging and Privacy: It's crucial not to keep raw passkey materials or full data blobs. By default, you should hash payloads, and treat AAGUID and device IDs as personal data, applying retention limits on them. (Feel free to reach out for our field-level telemetry schema!)

5) Measure What Matters from Day 1

• Here’s what we’ll track and how we’ll visualize it:
  • Conversion rate for "First signed onchain action" (think of it as the journey from just checking out the page to actually signing in and completing a successful UserOperation)
  • Sign-in success rates for passkeys versus traditional passwords/TOTP
  • Median Time-to-First-Transaction (TTFT) - basically, how long it takes from sign-in to first action
  • Paymaster spending per Weekly Active User (WAU) along with the refund rate
  • Volume of support tickets related to "can’t sign in" and "lost seed phrase" issues
• Setting benchmarks to help us hit our targets:
  • Google found that passkey sign-ins are four times more successful than using passwords. Plus, FIDO mentions that 69% of people have at least one passkey set up, and nearly half (48%) of the top 100 websites support them. Let’s use these figures as our external benchmarks! (source)

A Concrete Blueprint (with Code and Config You Can Use)

So, you want a solid blueprint that’s super handy, right? Well, I've got you covered! Here’s a ready-to-go plan that includes code snippets and configuration details that you can easily lift and adapt for your own projects.

Code Snippet Example

Here’s a quick example to get you started. This simple Python code will help you set up a basic server:

from http.server import SimpleHTTPRequestHandler, HTTPServer

class CustomHandler(SimpleHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write(b"Hello, world!")

if __name__ == "__main__":
    server = HTTPServer(('localhost', 8080), CustomHandler)
    print("Starting server at http://localhost:8080")
    server.serve_forever()

Configuration Details

• Server Port: The server runs on port 8080 by default. You can easily change this if needed.
• Response: Whenever you make a GET request, it responds with "Hello, world!".

Additional Resources

Need more details? Check out these links for deeper dives into the topics covered:

• Python's Official Documentation
• HTTP Server in Python

Final Thoughts

Feel free to tweak the code and config to suit your needs! It’s all about making it work for you. Happy coding!

Stage 0 -- Choose the Wallet Architecture

• Looking for that same-address user experience? Go with EIP-7702 “smart EOAs” and throw in some passkey validators.
• Need modular controls and want to cover gas fees? Check out ERC-4337 smart accounts paired with a passkey validator and a paymaster.

Stage 1 -- Client UX that Actually Converts

• Web: Make the experience smoother by using conditional mediation and autofill. Skip those separate “passkey” buttons! If a passkey is an option, lead with that; otherwise, direct users to email/OTP as a fallback. (developer.android.com)
• Android: Go ahead and integrate androidx.credentials with the Credential Manager. This setup should allow you to enable conditional creation, so you can auto-provision a passkey right after the user enters their password. This makes it super easy to migrate those legacy accounts without any hassle. (developer.android.com)
• iOS: For iOS, implement the ASAuthorizationPlatformPublicKeyCredentialProvider flows. Don’t forget to wire up the “reset passkey” feature using createCredentialRegistrationRequest to overwrite any old keys across all the user’s devices. That way, they have a seamless transition! (developer.apple.com)
• Cross-device Guidance: It’s really helpful to document one recommended provider for each environment (think iCloud, Google, or 1Password) and also list those setups that just won’t sync (like certain Windows Hello or Chrome-profile situations). This helps cut down on stranded users and support tickets. (help.coinbase.com)

Stage 2 -- Server logic that won’t wake you at 2am

• Make sure to enforce origin/RPID checks and replay protections; also, don't forget to validate UV/UP flags and keep an eye on counter monotonicity.
• When you parse the COSE_Key, grab the x and y values, then store the public key along with the credential ID and AAGUID. Just remember, never stash away any private materials!
• If you're leaning on hardware-backed authenticators, you'll want to check the attestation chain and make sure the AAGUID is on your allowlist via FIDO MDS. And hey, don’t skip logging that enrollment metadata for future audits! (fidoalliance.org)

Stage 3 -- Onchain Verification You Can Trust

• First off, let's talk about using the native precompile call (0x100) for signature verification. You’re looking at around 6,900 gas per verification on the Ethereum mainnet with EIP‑7951. If you’re working with the OP‑Stack or any other L2s that implemented RIP‑7212 earlier, keep in mind that the addresses might match but costs could vary a bit--so make sure to feature-detect at runtime. Check out more details here: (eips.ethereum.org).
• Smart Account Wiring:
  • In your validateUserOp(), you’ll want to compute h = sha256(authenticatorData || sha256(clientDataJSON)) and then call the precompile using (h, r, s, qx, qy).
  • It’s a good idea to add an s-malleability check in Solidity. Even though the precompile does a solid job verifying ECDSA, enforcing low-s values can help reduce unexpected issues down the road. For more info, check out this link: (developers.yubico.com).
• Session Keys:
  • You can set up short-lived permissions for low-risk activities (think in-game mints). Make sure to scope these by target contract, function selectors, and daily spending limits; and don’t forget to revoke them on logout. It’s wise to align your approach with ERC‑6900/7579 patterns. Get more insights here: (rhinestone.dev).
• Gas Policy:
  • To keep things running smoothly, consider sponsoring the first N transactions through a paymaster, complete with rate limits. Track the “sponsored conversion lift” compared to your control cohorts to gauge effectiveness.

Stage 4 -- Governance, Risk, and Compliance (GRC) Ready

• NIST Mapping in Your RFP: When you're drafting your request for proposal, don’t forget to mention that this implementation offers phishing-resistant authentication. With synchronized passkeys, you’re looking at AAL2 compliance, and for those device-bound passkeys, you'll meet AAL3 whenever it’s necessary. Oh, and make sure to include your attestation policy and the maintenance schedule for the AAGUID allowlist. You can check out more details here.
• Incident Playbook: Just in case a passkey provider runs into an outage or a regression, it’s super important to have a plan. Set things up so that it can automatically switch to a second enrolled passkey. Alternatively, you could use an OTP-once flow that instantly binds a new passkey if that works out--just remember to add in some extra verification for those more sensitive actions.

Emerging Best Practices We Apply in 2026 Builds

• Lead with passkeys, don’t hide them behind “More options.” Companies that took this route saw sign-in success rates soar to about 90% or even higher, plus a noticeable drop in password-reset requests. Check out more details on this from the FIDO Alliance.
• Opt for platform passkeys first. Make sure to include synced cloud managers like iCloud, Google, Microsoft, and 1Password for smooth cross-device access. It’s a good idea to document which combinations your support team backs up.
• For wallets, clarify “what you’re approving.” Break down session scopes (like expiry, contract, and limits) in simple terms--especially when dealing with 7702 delegation.
• Instrument everything. Your go-to-market (GTM) team should have access to real-time insights like “passkey vs OTP” funnels, “UserOperation acceptance” panels, and data on “paymaster spend per WAU.”

What This Delivers for You (GTM Metrics We're Committing To)

• Here’s what you can expect when we run our A/B tests over a period of 4-8 weeks:
  • A solid 20-35% bump in conversion rates for “first onchain action” compared to those password/seed-based setups.
  • A crazy 50-80% drop in “can’t sign in” and “lost seed” support tickets.
  • A nice 10-25% speedup in time to first transaction (TTFT) on mobile, thanks to Credential Manager and AutoFill-assisted passkeys.
  • A sweet 15-30% lower customer acquisition cost (CAC) for cohorts coming from performance channels, meaning fewer users are bailing out at the authentication stage.
• And we’re not just making this up! These results align with findings from other sources: Google has noted that passkeys achieve 4× higher success rates, and FIDO’s 2025 survey reveals that 69% of consumers have enabled at least one passkey, backed by widespread ecosystem support. (security.googleblog.com)

Where 7Block Labs Fits In Right Now

• Architecture and Delivery:
  • Wallet/Account Design and Implementation: We’re all about creating top-notch wallet designs, including passkey validators, session key modules, paymaster policies, plus those cool 7702/4337 hybrids. You can check out our custom blockchain development services and web3 development services to see how we bring these ideas to life.
  • Onchain Cryptography and Audits: Safety first! Our engineers team up with formal reviewers to deliver reliable verifiers, all carefully evaluated under our security audit services.
  • Platform Integration: We’ve got you covered across platforms with tools like Android Credential Manager, iOS AuthenticationServices, and Windows Hello/Edge. Plus, we handle backend WebAuthn attestation and AAGUID allowlists through our blockchain integration expertise.
  • Productization: We focus on solidifying processes, tracking AA telemetry, and linking Google Tag Manager to onchain KPIs. Our dApp development and smart contract development services are here to help you get the most out of your product.

A Quick and Handy Checklist for Sprint Planning

Required

• RPID and Origin Validation: Make sure to enforce RPID and perform origin validation, plus require UV for those sensitive actions. Check it out here.
• Attestation: Use the “direct” method during registration, verify it against FIDO MDS, and keep an AAGUID allowlist handy. More details on this can be found here.
• Precompile Path for P‑256: Make sure you precompile the path for P‑256 on every target chain, and runtime-detect 0x100, falling back only when it’s absolutely necessary. Check the specs here.
• Session Keys: Use session keys for those low-risk flows, clearly define scopes, and ensure you have visible revoke options. You can dive into this here.

Recommended

• Conditional Create (Android): Consider setting up a conditional create that automatically provisions passkeys for those legacy users. Find out more here.
• Cross-Device Policy Page: Create a policy page that lists the supported providers and any sync paths you want to disallow. Don’t forget to link it from your help center! You can check out an example here.
• Dashboards: Keep an eye on your dashboards that show sign-in success by method, drop-off by device, UserOperation acceptance reasons, and paymaster spending/WAU.

Appendix -- Practical bits

• How to compute the WebAuthn message hash
  • First off, let’s define CD as clientDataJSON (bytes) and AD as authenticatorData (bytes).
  • You can compute the hash with this formula: h = SHA‑256( AD || SHA‑256(CD) ).
  • After that, make sure to verify ECDSA P‑256 over h using (r, s) and the user’s P‑256 public key (qx, qy). For more details, check out the guide on Yubico's site.
• Gas expectations for on-chain verification
  • If you're working with the Ethereum mainnet (EIP‑7951), you can expect about ~6,900 gas per verification at 0x100. For OP‑Stack (RIP‑7212/Fjord), it’s P256VERIFY at 0x…0100 with a similar setup. A few Layer 2 solutions are starting at around ~3,450 gas. Just a tip: feature-detect instead of hardcoding those values. For the nitty-gritty, refer to the EIP docs.
• Real-world signals that passkeys are mainstream
  • WebAuthn Level 3 got the nod for W3C Candidate Recommendation status back in January 2026. Check it out on W3C’s website.
  • Coinbase’s Smart Wallet/Base help centers have detailed guides on setting up passkeys and their limitations, which just goes to show that passkeys are being used in real-world applications at scale. You can find more info here.

If you only want to remember three key “money phrases,” here they are:

• “Native P‑256 verification at 0x100” -- Say goodbye to seed phrases! This means you can have on-chain verifiable signatures. Check it out here: (eips.ethereum.org).
• “AAGUID allowlist + attestation enforcement” -- This gives you procurement-grade assurance that’s linked to actual hardware inventories. Get the details here: (fidoalliance.org).
• “Session keys with explicit scopes” -- Enjoy a one-tap user experience without the risk of giving blank-check approvals. Learn more at: (rhinestone.dev).

Personalized CTA

Hey there! If you’re the Head of Product or the CTO focused on hitting that Q2 2026 onboarding KPI for Android and iOS, and your security crew is asking for “AAL2/AAL3 mappings plus on-chain P-256 verification,” let’s chat! Book a quick 45-minute working session with 7Block Labs this week.

We’ll dive into your auth funnel, figure out the perfect attestation/AAGUID policy, and get you a proof-of-sign (precompile-verified) UserOperation on your target chain within 10 business days. After that, we’ll help you wire it right into your app with our awesome custom blockchain development services and a streamlined security audit to make sure procurement gives the green light for launch. Looking forward to working together!