Verifiable Timesheets: Prove Your Work Without Revealing Everything

23 May 2026

23 May 2026 by Luke Puplett - Founder

When you claim you have skills, how does an employer know it's true?

They don't. They can hire you and hope you can actually do the job. Or barrage you with tests, references, and background checks. Or both. But there's no instant way to verify: you actually did this work, you have this skill, with no room for exaggeration or AI-generated fantasy.

In regulated industries, this isn't optional—it's the law. Pilots must have flown within the past 90 days. Compliance officers need recent regulatory experience. Healthcare workers need recent clinical hours. Checking recency today means days of manual verification: hunting through references, hoping records exist, praying nothing got lost. Airlines, banks, and hospitals all face the same tedious, error-prone process.

The Trust Problem: CVs vs. Reality

An LLM can write a convincing CV in seconds. "500 hours of React. Led a team of 5 engineers. Shipped production systems." It sounds fantastic. But did any of it happen?

Employers know this. When you claim experience, they have two bad options:

• Hope they trust you and risk hiring someone who can't actually do the job

• Wait while they spend days calling references and hunting for documented proof

There's no way to verify instantly. No cryptographic proof. No independent way to check. Just hope and tedious manual verification.

Timesheets could prove it. But timesheets are documents—easy to falsify, hard to verify. Until now.

The Solution: Blockchain-Attested Timesheets with Selective Disclosure

When your timesheet is approved, we create a cryptographic snapshot of it: an immutable frozen record with all the details (work performed, skills used, dates, hours, approver signature). We build a Merkle tree from that data and attest the root hash to the blockchain—specifically, to Base network via the Ethereum Attestation Service (EAS).

Now your work has a permanent, verifiable record on-chain.

But here's the key: you don't have to reveal everything. Using ProofPack, you create selective-disclosure proofs. You can prove "I have 500+ hours of React experience" without revealing which clients you worked for, exact dates, or other skills. The verifier checks the proof cryptographically—no call to us needed, no trust required.

How It Works

1. Timesheet approved → frozen record created

When you submit your timesheet and it's approved, we create a FrozenTimesheet: an immutable snapshot containing your work details, extracted skills, approver signature, and dates.

2. Merkle tree built → root hash generated

We build a deterministic Merkle tree from the frozen data. Each leaf represents a piece of information (a skill, a day worked, the approver). The root hash is a single value that represents the entire timesheet cryptographically.

3. Root hash attested to Base blockchain

We publish the root hash to the Base blockchain via EAS. It's signed by us (Zipwire) and permanently recorded on-chain. Your work is now verifiable.

4. Create a selective-disclosure proof

You decide what to reveal. "React experience?" Prove it without disclosing client names. "Approved on this date?" Prove it without showing salary or hours. ProofPack generates a signed token (JWS) that cryptographically proves the disclosed claims come from the attested timesheet.

5. Verifier checks the proof independently

The employer, client, or service uses ProofPack to verify your proof. No call to us. No login. Just cryptographic verification: "Does this proof match the Merkle root on Base? Is the attestation valid? Can I trust these claims?" The answer is yes or no, with cryptographic certainty.

The Regulatory Problem: Proving Recent Work (Not Just Claims)

Some industries can't afford to gamble on CVs. They require employers to verify recency of work experience at hire time:

• Aviation: The FAA requires pilots to have made at least 3 takeoffs and landings in the aircraft type within the preceding 90 days. Flight instructors must meet recency requirements every 24 months. You can't fake this—your life and your passengers' lives depend on recent, proven experience.

• Financial services: FINRA and SEC regulations require proof of recent relevant experience for compliance and advisory roles. A hired candidate with a year-old CV claiming current market knowledge is a regulatory liability.

• Healthcare: Many states require documented proof of current licensure and recent clinical experience before hire. Patient safety means you need proof, not promises.

Today, employers in these industries verify recency the hard way: calling references, hunting through CV dates, requiring documented evidence. Days of work. Lots of room for fabrication or outdated information.

Verifiable timesheets solve this: a pilot applying for a job generates a proof of flight hours from the past 90 days—cryptographically signed, on-chain, tamper-proof. A compliance officer generates proof of recent regulatory work. An RN proves recent clinical experience. Instant verification. No CV fantasy. Just facts.

Why This Matters

No verification call required. Old way: employer calls your previous company and hopes someone remembers you. New way: they verify the proof cryptographically in milliseconds. No room for: "I forgot they worked here," or "we don't have records," or worse, coordinated deception.

AI-proof. CVs are easy to generate with an LLM. Blockchain attestations are not. Verifiable timesheets prove work happened—not because someone said so, but because it's cryptographically signed and on-chain.

Privacy-preserving. You reveal only what's necessary. Your past clients, exact salary, or other projects stay private. But the verifier can still trust the claims you do make—because they're backed by cryptographic proof, not word-of-mouth.

Permanent record. Your approved timesheets live on-chain forever. No lost references. No "I can't remember if they worked here." No convenient amnesia.

Portable. One timesheet, many uses. Prove hours to one employer, skills to another, contractor status to a third—all with the same on-chain record.

Real Use Cases

Job applications: "I have 500 hours of TypeScript experience." Create a proof. Employer verifies it instantly. No reference checks.

Regulatory recency requirements: Regulated industries (aviation, financial services, healthcare) often require proof of recent work experience. An airline hiring a pilot can instantly verify they've logged recent flight hours. A bank can prove a hire has recent compliance experience. Verifiable timesheets eliminate the tedious reference-check process and provide cryptographic certainty.

Client audits: "Can you prove the hours you billed?" Generate a proof of total hours and approver signature from your frozen timesheet. Cryptographically verifiable.

Contractor verification: Platforms matching freelancers to jobs can verify skills and experience directly from on-chain attestations instead of trusting self-reported profiles.

Compliance and background checks: Regulated industries (healthcare, financial services) need verifiable work history for hiring compliance. Blockchain attestation provides a tamper-proof record that satisfies regulatory requirements without manual verification calls.

Getting Started

Create and approve a timesheet. We automatically generate the frozen record and attest it to Base. Use the Zipwire API to mint a selective-disclosure proof for any claims you want to reveal. Share the proof (a compact JWS token) with anyone who needs to verify your work.

Learn more:

• ProofPack Documentation — Full specification, architecture, and code examples

• JavaScript Implementation — Browser and Node.js examples

• .NET Implementation — C# integration examples

Technical Details

Verifiable timesheets use:

• Merkle trees — Deterministic structures that allow selective disclosure of individual claims

• Base blockchain — Ethereum Layer 2, via EAS (Ethereum Attestation Service)

• ProofPack — Open standard for creating and verifying cryptographic proofs

• JWS tokens — Compact, portable proofs that work in HTTP headers and APIs

For technical specifications, see Attestation Schemas.

The Future of Work Verification

Timesheets were always meant to prove you worked. With verifiable timesheets, they finally do—cryptographically, privately, and without intermediaries. No more hoping people believe you. No more waiting for verification calls. Just proof.

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