The Problem With Certifying Spreadsheets & Data Files
Spreadsheets containing financial projections, pricing models, or project plans are frequently shared and then disputed. Who had which numbers when becomes a critical question.
In a world of deepfakes and digital manipulation, proving a file is authentic is becoming essential.
For analysts, accountants, project managers, data teams, this is not a theoretical risk — it is a daily reality. A startup shares financial projections with investors. The investors later claim different numbers were presented. Timestamped spreadsheets prove the exact figures that were shared.
How TimeProof Solves This
When you timestamp spreadsheets & data files with TimeProof, TimeProof uses client-side file hashing (SHA-256). That 64-character value is the unique fingerprint for the exact version you selected, and if even one byte changes, the hash changes too. Your file never leaves your device.
TimeProof proves file existence by anchoring file hashes to the Polygon blockchain. The blockchain records the hash, timestamp, and transaction ID permanently, so anyone can verify the record independently on Polygonscan without relying on editable metadata or a vendor-controlled database.
For analysts, accountants, project managers, data teams, that means creates a blockchain-anchored certificate proving the file is authentic and unaltered. timestamping spreadsheets preserves a snapshot of the exact data at a specific moment, proving the data existed in that form before any dispute about numbers arose.
Specific to Spreadsheets & Data Files
Timestamping spreadsheets preserves a snapshot of the exact data at a specific moment, proving the data existed in that form before any dispute about numbers arose. Common file formats include XLSX, CSV, ODS, NUMBERS, TSV, and TimeProof handles all of them. Whether you are using Excel, Google Sheets, LibreOffice, Numbers, the workflow is the same.
The Metadata Problem
Many people assume file metadata is sufficient proof. It is not.
Excel metadata shows last-modified date but not a reliable creation timestamp. Google Sheets version history requires account access. CSV files have no metadata at all.
A blockchain timestamp is independent of your file’s metadata. It is stored on the public Polygon blockchain, which no one controls. Even if every byte of metadata is stripped, your timestamp remains permanent and verifiable.
Step-by-Step: Certifying Your Spreadsheets & Data Files
Anchor the official outward-facing file before sharing it so the trust conversation starts with an independent authenticity record instead of unsupported assertions. Best used before publishing, delivering, listing, or formally submitting a file that third parties need to trust. Common files in this workflow include official releases, public listings, and submission packets. Typical reviewers or counterparties include buyers, platforms, and reviewers.
- Finalize the exact file you want others to treat as the official authentic version.
- Timestamp that file before publication, listing, or formal submission.
- Share the certificate and Polygonscan link with the file or keep them in the review packet.
- Timestamp later official replacements separately instead of treating one old certificate as proof for every revision.
Step 1: Select your file. Open TimeProof and drag your file onto the upload area. TimeProof accepts XLSX, CSV, ODS, NUMBERS, TSV and every other file format. The SHA-256 hash is computed entirely in your browser — your file never leaves your computer.
Step 2: Choose your timestamp type. Use scheduled timestamps for 1 credit per file, or use verified instant timestamps for 2 credits per file when immediate anchoring matters. Both produce permanent, identical proof.
Step 3: Confirm and anchor. Click the timestamp button. TimeProof computes the SHA-256 hash locally, sends it to the Polygon blockchain smart contract, and returns your proof. You pay zero gas fees — TimeProof covers all blockchain costs.
Step 4: Download your proof. You receive a PDF certificate and a direct link to the blockchain transaction on Polygonscan. Verified instant timestamps add a verified identity badge, and Legal-Grade adds the Courtroom-Ready PDF, JSON metadata, JWS identity attestation, and Complete Evidence ZIP.
Step 5: Add Legal-Grade if needed. Legal-Grade is a verified per-batch upgrade. Starter and Pro charge 50 credits for up to 25 files, then +2 credits per file after 25. Business charges 25 credits for up to 25 files, then +1 credit per file after 25. Enterprise includes Legal-Grade. It adds the Courtroom-Ready PDF, JSON metadata, JWS identity attestation, and Complete Evidence ZIP.
What You Receive
Every TimeProof timestamp for spreadsheets & data files includes:
- PDF certificate - a readable proof document for the exact spreadsheets & data files you timestamped, ready to keep with the project or share when timing becomes disputed.
- Polygonscan link - direct public verification of the on-chain hash, timestamp, and transaction.
Verified instant timestamps also include: 3. Verified identity badge - the certificate shows the timestamp was created by a verified account, which is useful when delivery timing, authorship, or submitter identity may later matter.
With the Legal-Grade upgrade, you also receive the core evidence-package components documented by TimeProof: PDF, JSON, JWS identity attestation, and a ZIP bundle.
- Courtroom-Ready PDF - a presentation-ready evidence certificate for disputes around certify its authenticity with blockchain proof, payment, originality, or formal review.
- JSON Metadata - machine-readable timestamp data for technical teams, audit trails, or structured evidence review.
- Identity Attestation (JWS) - a signed proof that ties the timestamp to a verified identity and can be verified through /.well-known/jwks.json.
- Complete Evidence ZIP - one bundle containing the Courtroom-Ready PDF, JSON Metadata, Identity Attestation (JWS), and supporting proof materials so counsel, clients, or reviewers can inspect the complete record in one place.
Why Blockchain vs Other Methods
TimeProof uses Polygon because analysts, accountants, project managers, data teams need proof that is fast to create, inexpensive to repeat, and easy for third parties to verify.
TimeProof proves file existence by anchoring file hashes to the Polygon blockchain. This gives reviewers a public record they can inspect independently on Polygonscan.
- Speed: about 2-second block times when verified instant proof matters.
- Cost: users do not buy crypto or manage gas fees because TimeProof covers blockchain costs.
- Public verification: counterparties, clients, auditors, or counsel can inspect the record independently on Polygonscan.
- Security: the record sits on a public, tamper-resistant network aligned with Ethereum.
- Permanence: the timestamp remains verifiable long after the spreadsheets & data files have been shared, reposted, or challenged.
Real-World Scenario
A file may be real, but a buyer, platform, reviewer, or partner wants an independent authenticity signal before treating it as official. The files at issue are often official releases, public listings, and submission packets. Typical reviewers or counterparties include buyers, platforms, and reviewers.
A startup shares financial projections with investors. The investors later claim different numbers were presented. Timestamped spreadsheets prove the exact figures that were shared.
A marketplace, reviewer, or counterparty asks for stronger proof of authenticity before accepting, publishing, or relying on the file. The timestamp and certificate give third parties a dated record tied to the exact file, which helps close the trust gap before a deeper dispute forms.
Related Comparisons
These comparisons help you measure this proof path against common alternatives that solve part of the problem but not the full timing-and-integrity chain.
- TimeProof vs Adobe Content Credentials: Compare proactive authenticity signaling with provenance credentials used inside compatible media ecosystems.
- TimeProof vs Registered Mail: See why mailing or courier records do not certify the exact digital file the way a timestamped hash does.
- TimeProof vs Notarization: Compare file-native trust proof with signature or attestation workflows when reviewers need confidence before relying on a file.
Related Guides
Use these related pages to go deeper on the legal, verification, or pricing context behind this workflow.
- Create Legal Evidence for Legal Documents: Escalate from proactive trust proof into a formal evidence package when a certified file may later face legal scrutiny.
- Pricing: Review the current credit and plan model for recurring certification workflows across teams or review cycles.
- How Blockchain Timestamping Works: Understand the verification model behind the certification record you are handing to third parties.
Pricing
TimeProof uses one unified credit balance, so you can certify spreadsheets & data files as part of normal work instead of waiting for a dispute.
- Scheduled timestamps: 1 credit per file - available to everyone, with proof available within 6 hours.
- Instant timestamps: 2 credits per file - available to verified subscribers, anchored in about 2 seconds.
- Legal-Grade: Starter and Pro: 50 credits up to 25 files, then +2/file. Business: 25 credits up to 25 files, then +1/file. Enterprise: included.
One-time packs start at $15 for 100 credits. Verified monthly plans start at $19/month and include identity verification for instant timestamps and Legal-Grade.
Timestamp key business spreadsheets using 1 scheduled credit each. Twelve monthly models would use 12 credits per year. Use scheduled timestamps for routine protection, verified instant timestamps when timing must be immediate, and Legal-Grade when the record may be challenged formally.
For spreadsheets & data files, the cost is based on the number of files you anchor, not the file size. Scheduled timestamps use 1 credit per file, while verified instant timestamps use 2 credits per file.
Privacy
Your spreadsheets & data files never leave your computer. TimeProof uses client-side file hashing (SHA-256). Only the 64-character hash string is sent for anchoring. Because SHA-256 is one-way, it is not possible to reconstruct the original file from the hash. That lets analysts, accountants, project managers, data teams protect client work, unpublished material, and high-value source files without exposing the underlying content.