Summary: Hey there! If you're in charge of exploring patient-facing blockchain apps, it's super important to focus on making the user experience smooth and easy for patients. At the same time, you want to make sure that everything is locked down tight in terms of security and meets those HIPAA standards! This guide dives into design and security patterns that are set for 2025, all based in the U.S. So, if you're curious about what’s coming up and how it’ll impact us, you’re in the right place! We've got all the info you need on interoperability rules, OAuth/NIST standards, and the must-know basics of Web3. These resources will guide you in creating healthcare apps that are not just user-friendly, but also compliant and reliable.

Blockchain healthcare app development: UX + Security Patterns for Patient-Facing Web3

Engineering Guidance: Not Legal Advice

Hey! Just a quick note: even though this article is full of engineering tips and tricks, it shouldn't be used as a replacement for legal advice. If you've got any legal questions or issues, it's a good idea to chat with a lawyer. They really know their stuff and can give you the best advice! Alright, let’s jump right into some cool engineering tips!

Understanding Your Project Requirements

Before diving into any project, it’s super important to have a solid understanding of what you actually need. Here are a few steps to help you really get a handle on those requirements:

1. Chat with Stakeholders: Take some time to catch up and talk things over with everyone involved. This covers everyone from clients and team members to the folks using our products. Getting their input can give you some fresh perspectives that you might not have thought about before.

2. Put Together a Requirements Document: Just jot everything down in writing. It's super helpful! Let’s lay out the goals, limitations, and requirements for the project. Having a well-organized document is like a treasure when it comes to ensuring everyone’s on the same wavelength.

3. Prioritize Your Needs: Let's be real--some requirements are definitely more important than others! Get together with your team and figure out what matters most. This way, you can put your energy into the areas that really count.

Design Considerations

Once you’ve nailed down what you need, it’s time to let your creativity flow and dive into the design process!

• Pick the Right Tools: Whether you're diving into coding or working on a project, it's super important to choose tools that fit what you're trying to achieve. There are definitely times when sticking with a popular framework makes a lot of sense. But then there are also those moments when a lesser-known tool really stands out and does the job even better!
• Keep Scalability in Mind: When you're designing, try to think ahead a bit. So, how’s your project planning to deal with growth? It’s super important to make sure your design can scale right from the get-go. Trust me, setting this up now will save you a ton of stress later on!
• Maintenance Plan: You know, a great project isn't just about getting it off the ground. Think about how you're going to keep the project fresh and make any updates as time goes on. Having good documentation and a tidy codebase really makes life easier when it comes to making changes down the road.

Testing and Quality Assurance

Hey, don’t forget about testing! It’s super important to make sure everything goes off without a hitch when you launch your project. Here’s a quick guide to help you keep things running smoothly:

• Set Up a Testing Framework: It's super important to get a solid testing framework in place right from the start. This will definitely help in spotting bugs and making sure everything runs smoothly.
• Get Real Users on Board: It’s a great idea to involve real users when you're running beta tests. Their feedback is super helpful and can really shine a light on problems you might not even be aware of.
• Continuous Integration: Get into the groove of continuous integration! This means setting up practices that help automate your testing and deployment processes, making life a lot easier and more efficient. This really makes it a breeze to catch any issues before they blow up into bigger problems.

Documentation is Key

You really can't underestimate the importance of good documentation. Here’s how to make sure it stays effective:

• Keep It Simple and Straightforward: Stick to everyday language and steer clear of complicated terms whenever you can. The aim here is to ensure that your documentation is easy for everyone to access.
• Add Some Examples: Whenever you get the chance, throw in some examples. They really help illustrate your point! They really help break down complicated ideas and make your instructions way easier to understand.
• Stay Current: Try to get into the routine of updating your documentation whenever there are changes. It really helps keep everything in check! That way, it'll always be fresh and helpful for everyone.

Conclusion

Just a quick reminder: these tips are great for engineering insights, but they definitely aren’t a substitute for legal advice. Make sure to stay in the loop and don't hesitate to reach out to professionals when dealing with legal matters. Happy engineering!.

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Why this matters now

• They've officially announced the deadlines for interoperability. So, here’s the scoop: per CMS's Interoperability and Prior Authorization Final Rule (CMS-0057-F), we’ve got a compliance deadline coming up on January 1, 2027. This applies to the Patient Access, Provider Access, Payer-to-Payer, and Prior Authorization APIs, all of which are built on HL7 FHIR standards. Mark your calendars! So, metric reporting is actually going to start in 2026. Hey there! So, when it comes to patient apps, they really need to be set up to manage FHIR data and keep users updated on their prior authorization status, ideally in almost real time. For more info, just click here! It’s got all the details you need.

Hey there! Exciting news--TEFCA is officially up and running, and it's really starting to take off! By January 2025, we can expect to see eight QHINs getting their official designation. Plus, can you believe that over nine million documents have already been exchanged through the TEFCA network? That's pretty impressive! Hey there! If you're working on patient apps, consider how you can have them connect to TEFCA networks through your BAA partners. It's worth exploring! If you want to dive deeper into this, just click here. It's a great resource!

• We've seen a change when it comes to identity and logging in. So, the NIST SP 800-63-4 is set to drop in July 2025, and it’s pretty exciting because it officially recognizes passkeys (or syncable authenticators, if you want to get technical) and subscriber-controlled wallets. This update is going to refresh the assurance guidance, which means you’ll have some solid info to use in your risk assessments.
  If you’re looking for more details, you can check it out here.

Right now, it seems like there's a bit of uncertainty when it comes to enforcing HIPAA web tracking. On June 20, 2024, a federal ruling came down that knocked out parts of the OCR’s guidance on unauthenticated webpages. Meanwhile, those authenticated portals are still being looked at closely. It's definitely a good idea to set up your analytics architecture to keep any PHI from slipping out, regardless of how the rules change over time. If you want to dive deeper into this topic, check out the details here. It’s definitely worth a read!

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A reference architecture for patient-facing Web3 healthcare

Design principle: So, PHI likes to keep stuff off the chain, while blockchains are responsible for managing things like provenance, consent, and those all-important verifiable proofs.

• Identity and Auth
• Patient Login: We’re hooking up with OIDC and SMART on FHIR scopes to help patients easily get to their EHR data. It's all about making things simpler for you! We've added in OAuth 2 as well. We've got you covered with 0 BCP (RFC 9700) and PKCE, and we're totally on board with the passkey trend, thanks to our WebAuthn support! Take a look at this link: hl7.org. It’s worth checking out!
• Optional Self-Custody: How awesome is this? We now have passkey-backed smart wallets (that’s ERC‑4337 smart accounts for those of you who like the tech lingo) all set to take care of signing consents and data grants. On top of that, we’re all about making your experience as smooth as possible. Thanks to Paymasters, you can enjoy gasless transactions! Learn more here: (cointelegraph.com).
• Assurance Alignment: We really need to make sure we're keeping track of our AAL/IAL decisions. It's just a smart move! We're getting in line with NIST SP 800-63-4, which means we're making sure that our synced passkeys at AAL2 are equipped with solid phishing resistance. It’s all about keeping things secure and smooth! If you’re looking for more info, check it out here: NIST Publications.
• Data flows First things first, you’ll want to grab that clinical data using payer or EHR FHIR APIs--specifically, we're looking at R4 here.

0. Start with 1 as your starting point, and don’t forget to keep an eye on R5 too! Don't forget to store any PHI in your HIPAA-compliant cloud with envelope encryption. It's super important to keep that info safe and secure! Just make sure to write only hashed pointers and the consent state onto the blockchain. (cms.gov).

• Getting consent sorted: To keep everything in check, make sure you pull in computable rules using FHIR Consent. Plus, don’t forget to have a signed consent document that’s easy to read stored separately--off-chain. Just to be safe, it’s a good idea to store a hash and some basic metadata on-chain. This way, you’ll make things easier to audit and ensure everything stays unchanged. (hl7.org).
• Sharing with Others: If you ever find yourself needing to pass along some information, you can go ahead and use W3C Verifiable Credentials (VC).

1. or SD-JWT credentials. This way, you can share specific details, like whether the coverage is active, without having to give away any personal health information. (w3.org).

• Messaging and support If you're working with in-app care teams or patient communities, you really can’t go wrong with using Messaging Layer Security (MLS). It's a smart move! This way, you get scalable end-to-end encrypted groups without having to mess around with custom crypto solutions. Give it a look right here: (ietf.org).

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UX patterns that reduce drop-off (and tickets)

1. When you're getting started, we’ll focus on passkeys. Don't worry about the wallet; it's totally optional!

• Allow users to log in with a passkey by using Face ID, Touch ID, or Windows Hello. If they need a wallet, we’ll just set up a smart account for them behind the scenes--no stress on their part! Hey, have you seen how Coinbase’s smart wallet is shaking things up? They’re using passkeys and gas sponsorships, which means you can forget all about those annoying seed phrases and pesky fees. It's pretty cool! (cointelegraph.com). Don't forget to jot down the entire passkey lifecycle in the Help Center. This should cover everything from renaming them to recovering lost ones and even how to delete them. Make sure to use the same easygoing language style that people love in their favorite wallets. (help.coinbase.com).

2) Progressive Disclosure of “Crypto”

How about we change “sign transaction” to “sign consent request”? Sounds good? "Basically, it’s a simpler way to explain things, and it fits nicely with the EIP-712 typed data, which really helps in keeping those phishing scams at bay." Also, we're going to stick with a steady domain separator that has the app name, version, and chainID included. If you want to dive deeper into that, you can find more info right here: (eips.ethereum.org).

• Hey, before you go ahead and click that sign button, let’s take a moment to run through how this will all play out. It's crucial to get a clear picture of what data you're sharing--like the types of FHIR resources, the time frames we're talking about, and why you’re using it in the first place. This should align with the meaning of the Consent resource that patients may come across in their portals. If you’re looking for more info, you might want to take a peek at this link: (hl7.org). It’s got some great insights for you!

3) Gasless, One-Tap Actions

• It's super easy to sponsor transactions for updating consents and handing out credentials - just use ERC-4337 Paymasters! On top of that, it automatically sets USDC for fee sponsorship. This means users can totally skip the hassle of managing ETH. Check it out here!.

4) Plain-Language Interoperability Status

Hey there! Just a heads-up: if you have any updates on the payer's "prior authorization" status or reasons for appeals, make sure to share those within one business day. It’s important to stay in line with what CMS expects. Hey, just a quick reminder to add those links to the payer policy! You can find it right here: hklaw.com. It’s super important!

1. TEFCA-aware copy
   So, if you’re teaming up with a data-exchange partner that's in a QHIN, don’t forget to label those specific records as “TEFCA network.” It’s an important step to keep everything organized! Hey, I think it would be super helpful to add a tooltip that breaks down what nationwide exchange is all about, along with the options for opting out. It could make things a lot clearer for everyone! If you’re curious to know more, just click here for all the details!

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Security patterns that pass audits (and scale)

1. Make sure to keep any personal health information (PHI) off the blockchain, but you can still include proof of it on the chain. Make sure to keep your PHI safe and sound in a secure place. Instead of storing the actual files, just jot down salted, keyed hashes of your important stuff, like policy PDFs and consent forms, onto the ledger. This way, you're keeping things secure while still keeping track of everything! Hey, just a heads up--it's super important not to put raw identifiers or re-identifiable hashes on public chains. You definitely want to steer clear of that! If you’re diving into HIPAA de-identification, you’ll want to follow the Safe Harbor guidelines. Basically, this involves getting rid of 18 specific identifiers. Alternatively, you could have an expert take a look and make the call for you. Hey, just so you know, IP addresses and complete dates are considered identifiers! You can check it out more here: law.cornell.edu.

2) Computable Consent with Cryptographic Receipts

• Use HL7 FHIR Consent to create rules that machines can actually enforce. Just think about these key elements: the actor, the action, the purpose, and the data period. You’ll need to start by signing an EIP-712 “ConsentGrant” message off the blockchain. After that, go ahead and anchor the hash of that message on-chain. With this method, you still get to keep your HIPAA right to make changes, which is pretty great. It means you can easily add new consents and connect them to the updated record rather than just wiping out the history. If you want to dive deeper into the details, just click here. Happy exploring!

Example EIP‑712 Typed Data for Patient Consent:

Let me give you a straightforward example of how to set up EIP-712 typed data for patient consent. It’s really not that complicated! Using this format really helps make the consent info clear and keeps it secure.

Structure of the Typed Data

{
  "domain": {
    "name": "PatientConsent",
    "version": "1",
    "chainId": 1,
    "verifyingContract": "0xYourContractAddressHere"
  },
  "message": {
    "patient": {
      "name": "John Doe",
      "dateOfBirth": "1990-01-01",
      "medicalRecordNumber": "MRN123456"
    },
    "consent": {
      "dataShared": ["medicalHistory", "labResults"],
      "expiry": "2024-01-01T00:00:00Z"
    }
  },
  "primaryType": "Consent",
  "types": {
    "EIP712Domain": [
      { "name": "name", "type": "string" },
      { "name": "version", "type": "string" },
      { "name": "chainId", "type": "uint256" },
      { "name": "verifyingContract", "type": "address" }
    ],
    "Consent": [
      { "name": "patient", "type": "Patient" },
      { "name": "consent", "type": "ConsentDetails" }
    ],
    "Patient": [
      { "name": "name", "type": "string" },
      { "name": "dateOfBirth", "type": "string" },
      { "name": "medicalRecordNumber", "type": "string" }
    ],
    "ConsentDetails": [
      { "name": "dataShared", "type": "string[]" },
      { "name": "expiry", "type": "string" }
    ]
  }
}

Breakdown of the Data

• Domain: Here, you'll find some background info on the contract and the specific version we're working with.
• Message: This part has all the important info about the patient, plus the consent details.
• Primary Type: This shows us the main structure we're putting our signature on.
• Types: In this section, we'll break down the different types we use in our messages. We want to make sure everyone gets what each part is all about!

Go ahead and tweak any of these fields to fit your needs!

{
  "types": {
    "EIP712Domain": [
      {"name":"name","type":"string"},
      {"name":"version","type":"string"},
      {"name":"chainId","type":"uint256"},
      {"name":"verifyingContract","type":"address"}
    ],
    "ConsentGrant": [
      {"name":"patientFhirId","type":"string"},
      {"name":"consentId","type":"string"},
      {"name":"purposeOfUse","type":"string"},
      {"name":"resourceTypes","type":"string"},
      {"name":"dataPeriodStart","type":"uint256"},
      {"name":"dataPeriodEnd","type":"uint256"},
      {"name":"revocable","type":"bool"},
      {"name":"nonce","type":"uint256"}
    ]
  },
  "primaryType": "ConsentGrant",
  "domain": {
    "name": "YourApp Consent",
    "version": "1.0",
    "chainId": 8453,
    "verifyingContract": "0x..."
  },
  "message": {
    "patientFhirId":"Patient/123",
    "consentId":"consent-abc123",
    "purposeOfUse":"TREATMENT",
    "resourceTypes":"Observation|Condition|MedicationRequest",
    "dataPeriodStart":1704067200,
    "dataPeriodEnd":1735689600,
    "revocable":true,
    "nonce":42
  }
}

This makes it easier for patients to grasp what's happening with their information. Plus, it keeps everything safe by using domain separation and nonces. It's also a great match with the FHIR Consent fields, which is a nice bonus! Take a look at this: (eips.ethereum.org).

3) OAuth 2.0 Toughened for Healthcare

• Make sure to stick with OAuth 2. Hey there! So, when it comes to security best practices in BCP (RFC 9700), let's make sure we’re using PKCE everywhere. It's super important! Also, if you're dealing with confidential apps, consider implementing push authorization requests (PAR)--they're a game changer. And don’t forget about sender-constrained tokens; options like DPoP or MTLS are definitely the way to go. Happy securing! Make sure to steer clear of implicit flows, okay? It’s really important to be super strict about how you handle redirect URIs. And don’t forget to change up those refresh tokens regularly! Trust me, it's a good practice! You can check out more details here.

4) Getting Familiar with SMART on FHIR 2.2 + USCDI v3 Alignment

First things first, let's kick things off by rolling out the SMART App Launch 2. 2 (R4. 0.

1. This is something that both the ONC and CMS refer to. Just a heads-up: you want to make sure your FHIR client is set up properly. Check that it can handle discovery, scopes, token introspection, and both patient- and provider-launched flows. It’s super important to have all of that sorted out! Make sure to stay tuned for HTI‑1’s timeline update on USCDI v3. It’s going to be the new standard starting January 1, 2026, and you won’t want to miss it! Hey, just wanted to give you a quick heads-up--there’s a chance that enforcement discretion could push back delivery to March 1, 2026. If you're looking for more info, check it out here!

5) Cryptographic Credentials for Minimum Disclosure

• Let's tackle the W3C VC 2 issue. You've got the credentials for stuff like "coverage is active," "age is over 18," or "trial eligibility has been pre-screened." This allows patients to share specific versions of SD-JWT with verifiers who only need particular claims. Oh, and just a quick note--VC 2! So, in May 2025, 0 officially got its W3C Recommendation status. Then, just a little later, in November 2025, SD-JWT was standardized as RFC 9901. Pretty exciting stuff! You can find more details right over here. Take a look!

6) Wallet Security That Respects Healthcare Risk

Why not set up some smart accounts that use passkeys and follow the ERC‑4337 standard? Plus, you won't even have to worry about gas fees because a sponsor will cover those for you! It's really important to have a reliable 2-of-3 recovery system ready to go. Think about setting up something that includes the patient's device, a recovery contact, and some backup from the provider desk that uses knowledge-based authentication (KBA). This way, if something goes wrong, you're all set to get back on track smoothly! Don't forget to set up some rate limits, and be sure to have those session keys expire after a certain period. It’s a good way to keep everything secure! If you're working with bundlers, definitely keep tabs on how the 4337 ecosystem is evolving. It’s pretty interesting stuff, like the new mempool rules, the audits for EntryPoint, and proposals for signature aggregation, like ERC-7766. There’s a lot happening, and it’s worth your attention! Take a look at this: (docs.erc4337.io). It’s got all the info you need!

So, if you're checking out MPC wallet vendors for your embedded wallets, it's super important to ask them about their approach to vulnerabilities. You definitely want to get the lowdown on how they handle issues, especially in light of those "BitForge" class problems that popped up in 2023. Transparency is key! Don't forget to check out their SOC2 and ISO proof as well! If there's even a chance that the vendor could stumble upon any telemetry related to PHI, it's a good idea to get a Business Associate Agreement (BAA) in place to keep yourself covered. Better safe than sorry, right? If you want to dive deeper into this topic, check out the link here: coindesk.com. Happy reading!

1. Secure patient messaging that’s totally end-to-end encrypted.

• Hey, let’s get those group chats going with MLS (RFC 9420) and don’t forget to check out the 2025 architecture guidance in RFC 9750! This approach lets us manage FS/PCS for bigger groups much more efficiently and makes it easier for everyone to reconnect. It's definitely a lot more scalable than those random Double Ratchet groups we've been using. Take a look at this: ietf.org. It's pretty interesting!

Front-end Supply Chain Defense (Web & Mobile)

Don’t forget to set up a solid Content Security Policy (CSP) with nonces and hashes. It’s super important for keeping things secure! And when you’re pulling in assets from CDNs, make sure to use Subresource Integrity (SRI). It’s a great way to ensure everything is safe and sound! Just a friendly reminder to make sure you set up your reporting endpoints! And when you're coding, try to steer clear of using eval or inline scripts unless you really have to. It’s better for security! If you're using third-party scripts, teaming them up with Subresource Integrity is a really clever idea. (developer.mozilla.org).

When it comes to mobile, definitely emphasize the importance of SSL pinning, tamper detection, and making sure to run those integrity checks during runtime. It’s really crucial to keep analytics separate to make sure that any Protected Health Information (PHI) doesn’t accidentally end up in your event payloads. Things are getting a bit more complicated with web tracking on unauthenticated pages, and let’s not forget that the rules for authenticated pages are tightening up as well. So, staying on top of this can save you a lot of headaches down the line! (nortonrosefulbright.com).

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What to put on-chain (and what not)

Good Candidates:

• Consent anchors: This part involves creating a hash from a human-friendly PDF and another hash from the computable FHIR Consent JSON. Hey, just a quick reminder to include a timestamp, the issuer's DID, and a link to that audit storage that can't be changed. Oh, and make sure it doesn't contain any PHI! If you want to dive deeper into it, you can check it out here. Happy exploring!
• Credential Status Lists (Revocation): So, when we mention this, we're diving into VC Bitstring Status Lists. It's a really smart and space-saving way to manage revocation while keeping patient identities under wraps. Hey, if you're interested, you can check out all the details here. It's worth a look!
• Research participation attestations: These are pretty simple. They just show your enrollment status and which group you're in, plus some SD-JWT presentations for the study sites. If you're looking to explore more, just check out the details here. Happy reading!

Avoid:

So, we've got raw PHI, those tricky quasi-identifiers, and those persistent encrypted blobs--think IPFS, Filecoin, or Arweave. You know, the ones that just stick around and don’t really let you delete or rotate keys easily? Yeah, those can be a real headache! Just a quick reminder: HIPAA lets you make changes to your health records, and if you’re in other areas, GDPR has some solid rules about deleting personal data. Make sure to store PHI safely and don’t forget to switch up those encryption keys from time to time. It’s a simple way to keep everything secure! (law.cornell.edu).

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FDA device edges: if you touch SaMD

Hey there! If your app is part of the medical device world, just a heads-up: when it comes to premarket submissions for those “cyber devices,” make sure you include a Software Bill of Materials (SBOM). Plus, don’t forget to have some strong cybersecurity measures in place. It’s really important! The FDA is seriously encouraging companies to step up and take charge when it comes to patching and handling vulnerabilities. Hey, just a quick reminder: don’t just throw wallets or dapps into your device user interfaces without having a solid supply chain strategy and a Software Bill of Materials (SBOM) ready to go. It’s super important to have those plans in place first! For more info, feel free to hop over to the FDA website and check it out!

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Practical, emerging patterns we’re shipping in 2025

• Easy Patient Access and Clear Prior Authorization Info.
• Integrate claims and prior authorization statuses right into patient apps using FHIR, and ensure those updates roll out within one business day. Also, make sure to jot down the reasons for denial and the timelines you get from the payers. It’s a good idea to keep a log of the denial letter's hash on the blockchain too, since that will help you verify where it came from when it’s time to file an appeal. (cms.gov).
• So, let's talk about "proof-of-coverage" when it comes to venture capital.
• You can go ahead and issue a VC 2. You’ve got a credential from the payer’s OIDC issuer that includes some key details, like {member_id pseudonym, whether coverage is active, and what plan tier you're in}. With this setup, you can show pharmacies or DME providers that "active = true" using SD-JWT, and the cool part is, you won’t have to share any personal info like your MRN or name. It's all about keeping your details private while still getting the information across! (w3.org).
• TEFCA-informed “record locator”
• Connect with your HIN/QHIN buddy to track down the documents you're after. Before you go ahead and collect any documents, make sure to show your patients a VC that lets them know how many documents are available. It's a good way to keep everything transparent and keep them in the loop! Once the user gives the green light, your server can grab the info using TEFCA and store it off-chain. Hey, just a quick reminder--make sure you log those retrieval events on-chain so we have everything sorted for auditing later. Thanks! (rce.sequoiaproject.org).
• A safe chat option for getting help with your care journey.
• We've set up end-to-end encrypted (E2EE) groups for each care episode using MLS. Here's the neat thing: messages just contain record references, like those FHIR Resource IDs, so there’s no personal health info (PHI) being sent around at all. Pretty cool, right? When you're working on presentations, they gather data from SMART while keeping the scopes to a minimum for security. If you want to dive deeper into the details, just head over to this link: (ietf.org). It's got everything you need!

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Build to U.S. regulatory timelines (so your roadmap lands)

• CMS APIs: Quick note for you! The reporting for usage metrics is set to start on January 1, 2026. And if you’re curious about the full API functionality compliance, that's expected to roll out by January 1, 2027. Make sure to set up your analytics in a way that captures all the necessary public metrics. Also, don’t forget to prepare for handling opt-in and opt-out messages! If you want to dive deeper into the details, just click here. You'll find all the info you need!
• ONC HTI-1: Just a heads up--starting January 1, 2026, we're going to see USCDI v3 become the new standard. Certified developers are getting a bit of a break when it comes to enforcement--until March 1, 2026. This is all due to some funding issues that popped up in 2025. Hey there! Just a quick reminder that it’s really important to ensure your data model and app filters are compatible with USCDI v3. This version covers stuff like SOGI (Sexual Orientation and Gender Identity) and SDOH (Social Determinants of Health), so you’ll want to make sure you're all set on that front! If you’re looking for more details, you can check it out here. It’s definitely worth a look!
• HIPAA Web Tracking: So, when we're talking about analytics on pages that require a login, you should really treat that data like it's PHI--protected health information. Self-hosting is definitely the way to go! Keeping things simple is key, and it's probably best to avoid sharing across different sites.
  While some sections of the OCR's bulletin might be off-limits for public view, don't let your guard down just yet. There's still going to be some close examination ahead! If you want to really explore this topic, check it out here. It's a great read!

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90‑day implementation plan (what 7Block Labs does on engagements)

• Weeks 0-2: Setting Up Risk and Structure. Alright, let’s kick things off by diving into our threat model. First up, we need to clear up who the Business Associate (BA) is according to HIPAA. We'll also figure out which data should stay off-chain and draft some wireframes to improve the user experience for consent.
• Weeks 2-6: Building the Basics of Identity and Consent. Alright, let’s jump into the topics of identity and consent. We're gearing up to roll out OIDC/SMART login using passkeys, which should make everything feel way more secure and user-friendly. Plus, we'll be integrating ERC-4337 wallets that come with sponsored gas--such a game changer! On top of that, we're diving into FHIR consent and EIP-712 signing to make sure everything runs smoothly. Exciting times ahead! And hey, we’re also going to get started on a VC 2! We're rolling out a pilot program for 0 issuance to demonstrate that coverage is active. ”.
• Weeks 6-10: Interoperability and Auditing. Alright, let’s shift gears and talk about interoperability and auditability next. So, what this involves is linking up with CMS Patient Access, making cards that display the statuses of prior authorizations, and establishing on-chain anchors for things like consent forms and denial letters. We're excited to let you know that we'll be starting the rollout of CSP/SRI soon!
• Weeks 10-13: Getting E2EE Messaging Ready and Fine-Tuning for Launch. Alright, now let’s dive into end-to-end encrypted messaging using MLS-based chat. We'll be diving into DAST and SAST, getting our OAuth BCP controls all set up, and making sure we have an incident playbook ready to go. Hey, just a quick reminder! Let's make sure we don't overlook the tabletop exercise and getting our production runbook all set before we go live. Thanks!

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Anti‑patterns to avoid

"Storing encrypted PHI on IPFS works well." ” Honestly, it's not. Just a heads up: those key exposure or re-identification risks can lead to a breach that you really can't fix later on. To keep things secure, it's a good idea to store PHI in a managed storage solution and only put proofs on the blockchain. This way, you stay safe while still making sure everything is verifiable. (law.cornell.edu).

• "I prefer using Implicit Flow since it's just so much easier to work with." ” Just don’t. Why not use the Authorization Code with PKCE instead? It's a solid choice, and following the BCP 9700 recommendations will really help you out. Seriously, just take my word for it on this one. (rfc-editor.org).
• "Seed phrases for patients." How about this: why not try using passkeys with smart accounts? Plus, you could cover the gas fees too. Sounds like a win-win! If you're a really dedicated power user, you might want to think about bringing your own wallet. But honestly, most people probably won't need to bother with it. (cointelegraph.com).
• “One‑and‑done consent. Not exactly! HIPAA actually gives you the right to make changes, while FHIR Consent lets you update things and set some exceptions. So, just a friendly reminder: make sure to append instead of overwriting! (law.cornell.edu).

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KPI ideas for product and compliance

So, let’s dive into the onboarding process and see how passkeys compare to our trusty old passwords. Are passkeys really better? And while we're at it, we'll also take a look at how often people successfully create wallets and how long it usually takes to sign consent.
(csrc.nist.gov). We're taking a close look at how the Patient Access API is being used and making sure it lines up perfectly with the CMS reporting standards for 2026.
(cms.gov). Hey, do you know how long it usually takes for a payer’s prior authorization update to show up in the app? We're really hoping to keep it under a business day! You can check out more about this here. Hey, let’s make sure we monitor how the CSP/SRI violation rates trend after we roll this out. This is a big shift from just reporting to actually enforcing it! (developer.mozilla.org).

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Quick checklist for your build

• Identity Hey, if you get a chance, take a look at Passkeys (WebAuthn) and see how they fit into the AAL guidelines from NIST 800‑63‑4. It's pretty interesting stuff! If you want to dive deeper into the topic, you can check out more details here. Enjoy exploring!
• Take a look at OAuth 2. So, we’ve got a solid set of 0 BCP 9700 controls lined up, which includes some important stuff like PKCE, PAR, and DPoP/MTLS. If you want to dive deeper into the details, just click here for more info!
• Interoperability
• Let's take a look at SMART on FHIR 2. Let's dive into two flows and get a little refresh on USCDI v3! Hey, make sure you take a peek at the CMS timelines laid out in the roadmap! They’re super helpful. You can check out all the details right over here.
• Consent + credentials Hey, could you check out FHIR Consent and the EIP-712 receipts that are linked to the blockchain? Thanks! For more info, check this out here. It's got everything you need!
• Check out VC 2.
  So, let’s talk about SD-JWT and how it lets you share only what you need to when it comes to non-PHI attestations. It’s pretty neat because you can pick and choose what info you disclose without throwing everything out there. This way, you keep things more private while still proving what you need to. Check it out here.
• Storage + chain Just a quick reminder to make sure you keep any personal health info (PHI) off the blockchain. You can still share proofs on-chain, though - just be sure to keep that sensitive data private! Steer clear of using IPFS or Arweave when it comes to handling PHI. If you're looking for the regulations, you can check them out here.
• Front-end security
• Make sure to set up a strong Content Security Policy (CSP) and Subresource Integrity (SRI). It’s also a good idea to use self-hosted analytics. And hey, don’t forget to steer clear of including any Protected Health Information (PHI) in your events! For guidelines, visit MDN.
• Messaging
• Take a look at MLS for secure group chats with end-to-end encryption. If you want to check out all the details, just click here. It's a good resource!

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The bottom line

When it comes to using blockchain in healthcare, it’s not just a matter of dumping patient records onto a chain. It’s actually about making sure that everything--like where the data comes from, patient consent, and how information gets shared--is straightforward, easy to verify, and user-friendly. And of course, we have to keep it all compliant with HIPAA and U.S. regulations. interoperability standards. So, we're all about using passkeys and smart accounts to make your experience as smooth as possible. We're also tapping into FHIR and OAuth BCP for easier data access, not to mention VC 2. Pretty cool, right? With 0/SD-JWT for minimal disclosure, you can totally build a Web3 patient experience that’s not just super reliable for clinicians, but also easy for patients to understand and straightforward for auditors to verify. It’s all about keeping it simple and effective!

Are you in need of a practical architecture review or maybe a little kickstart for your roadmap over the next three months? Well, look no further--7Block Labs is here to help! We specialize in customizing those patterns so they align seamlessly with your payer/EHR ecosystem and meet all your compliance needs. Let's make it happen together!

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Sources and standards referenced

Hey, make sure to take a look at the CMS-0057-F Interoperability & Prior Authorization timelines and the API requirements. It's really important stuff! If you’re looking for more details, check this out here. It's got all the info you need!

• Make sure you catch up on the newest updates about TEFCA's QHIN designations and how much is being exchanged. Check out all the details right here. You won't want to miss it! Hey there! Just a heads up - NIST SP 800‑63‑4 is set for some updates in July 2025. They're rolling out cool new features, including passkeys and subscriber-controlled wallets. Exciting stuff ahead! If you’re looking for more details, check it out here! Hey there! If you’re interested in security, you should definitely look into OAuth 2. Check out RFC 9700 for some key insights on Security BCP! If you want to dive deeper into it, you can check it out here. Happy reading!
• The SMART on FHIR App Launch (2). Check out the cool stuff happening with FHIR R5 resources! They're pretty exciting. If you want to dive deeper, just click here. Hey there! If you’ve got some questions about HIPAA, you might want to check out the de-identification rules outlined in 45 CFR 164. They really dive into how to keep personal info safe while still being able to use data for research and other important stuff. It’s pretty interesting! You’ve got the right to access your information (514) and also the ability to make changes if needed (45 CFR 164).

1. here.

• The W3C Verifiable Credentials 2.0. Hey, if you're looking for something interesting, you should definitely check out Recommendation and SD-JWT RFC 9901! You can get all the details here. It’s worth a look! If you're into blockchain, you might want to check out the ERC-4337 account abstraction docs. They've got some pretty handy information about gas sponsorships, also known as Paymasters. Check it out here. Hey there! If you’re curious about secure messaging, you might want to check out the MLS protocol and its setup for end-to-end encrypted group chats. You can find all the details here. Happy reading!
• Want to catch up on the latest tips for implementing CSP and SRI? Check it out here!
• And hey, make sure you check out the FDA's cybersecurity advice for medical devices. They've got some important stuff about SBOM and patching that you won’t want to miss! Check it out here.

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