Proving Spreadsheets & Data Files

The Problem With Proving 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.

Without proof, it becomes your word against theirs in any dispute about timing.

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 permanent evidence that your file existed at a precise moment in time. 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: Proving Your Spreadsheets & Data Files

Choose the exact file you may later need to defend, then anchor proof before later copies, renames, or edits blur the timeline. Best used when a defensible version exists. Common files in this workflow include signed documents, source files, and milestone exports. Typical reviewers or counterparties include clients, counsel, and auditors.

1. Identify the exact file whose existence matters, not a later export or renamed copy.
2. Timestamp that version while it is still in the state you may later need to verify.
3. Store the certificate and Polygonscan link with the evidence bundle or project archive.
4. Timestamp later milestone versions separately instead of treating one early anchor as proof of every later edit.

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:

1. 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.
2. 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.

4. Courtroom-Ready PDF - a presentation-ready evidence certificate for disputes around prove it existed on a specific date, payment, originality, or formal review.
5. JSON Metadata - machine-readable timestamp data for technical teams, audit trails, or structured evidence review.
6. Identity Attestation (JWS) - a signed proof that ties the timestamp to a verified identity and can be verified through /.well-known/jwks.json.
7. 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 team needs to show that a file already existed before a later submission, dispute, accusation, or public release changed the stakes. The files at issue are often signed PDFs, source archives, and deliverable exports. Typical reviewers or counterparties include counsel, auditors, and counterparties.

A startup shares financial projections with investors. The investors later claim different numbers were presented. Timestamped spreadsheets prove the exact figures that were shared.

Opposing parties rely on editable metadata, screenshots, or after-the-fact records instead of independent timing proof. The public anchor ties the exact-file hash to a defensible date even if the file is later renamed, copied, or stripped of metadata.

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 Email Proof: Compare informal self-send habits with independent proof of when the exact file already existed.
• TimeProof vs Wayback Machine: See why web-archive capture is not the same as timestamping the underlying file before later publication or copying.
• TimeProof vs Poor Man’s Copyright: Compare folk ownership habits with anchored existence proof when timing and exact contents matter.

Related Guides

Use these related pages to go deeper on the legal, verification, or pricing context behind this workflow.

• Archive Legal Documents Immutably: Extend baseline existence proof into longer-term retention when the file may need to be preserved for later disputes or audits.
• Create Legal Evidence for Legal Documents: Escalate a clean existence record into a formal package when the matter is moving toward legal review.
• How Blockchain Timestamping Works: Review the hashing and public anchoring model behind file-existence verification.

Pricing

TimeProof uses one unified credit balance, so you can prove 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.