Understanding Blockchain Timestamps
Learn how blockchain technology creates tamper-proof proof of existence for your documents.
What is Blockchain Timestamping?
Blockchain timestamping is a way to prove that a document, file, or piece of data existed at a specific point in time — without trusting any central authority.
The Simple Analogy
Imagine mailing yourself a sealed envelope. The postmark proves the contents existed on that date. Blockchain timestamping is the digital equivalent — except the "postmark" is recorded on a public blockchain (Bitcoin, Ethereum, etc.), visible to everyone forever, and mathematically impossible to forge.
Cryptographic Hash
Your file is converted into a unique "fingerprint" (hash). Even a tiny change creates a completely different fingerprint.
Blockchain Anchor
The hash is anchored to a blockchain — Bitcoin, Ethereum, or other networks. These are public, immutable ledgers that cannot be altered or erased.
Verifiable Forever
Anyone can verify the timestamp independently. No account needed. No trust required. The math speaks for itself.
Bitcoin vs Ethereum
TimeAnchor supports timestamps on both Bitcoin and Ethereum-compatible chains. Each has its strengths. You can verify individual files or entire folders.
Bitcoin
- •Most secure — largest proof-of-work network
- •Longest track record — running since 2009
- •OpenTimestamps protocol — free, open standard
- •Timestamps aggregated into single transactions (cost-efficient)
Best for: Maximum security and legal credibility
Ethereum & EVM Chains
- •Smart contracts — programmable timestamping
- •Faster confirmations — blocks every ~12 seconds
- •Layer 2 options — Polygon, Arbitrum, Optimism
- •Direct hash embedding in transaction data
Best for: Developer workflows and smart contract integration
How It Works
Create a Hash
When you want to timestamp a document, a cryptographic hash (SHA-256) is computed. This hash is a fixed-length string that uniquely represents your file. The original file never leaves your device.
Anchor to Blockchain
The hash is submitted to a timestamping service or embedded directly in a blockchain transaction. For Bitcoin, services like OpenTimestamps aggregate many hashes and anchor them together. For Ethereum, the hash can be stored in transaction data or emitted as an event.
Receive Your Proof
You receive proof of the timestamp — either an .ots file (Bitcoin) or a transaction hash (Ethereum). This proof links your document to a specific block and time. Keep it safe — it's your evidence.
Verify Anytime
Anyone with the original file and the proof can independently verify the timestamp. No trust required — the verification is purely mathematical. That's what TimeAnchor does.
Why It Matters
Proving when something existed has real-world consequences. Blockchain timestamps provide evidence that's independent, verifiable, and permanent.
| Use Case | Why Timestamps Help |
|---|---|
| Intellectual Property | Prove you had an idea, design, or invention before anyone else — establishing prior art without filing patents. |
| Legal Evidence | Contracts, agreements, and communications can be timestamped to prove they existed in a specific form at a specific time. |
| Research & Academia | Timestamp research data, findings, or papers to establish priority and protect against plagiarism claims. |
| Creative Works | Writers, artists, and musicians can prove when they created their work — useful for copyright disputes. |
| Software & Code | Timestamp git commits, releases, or codebases to create verifiable audit trails and prove code integrity. |
| Compliance & Audit | Create immutable records for regulatory compliance, demonstrating that documents weren't altered after the fact. |
Our Products
TimeAnchor is built by Aramantos Digital to complement our timestamping products.
ProveChain
Our document timestamping service for individuals and businesses. Upload documents, get blockchain-anchored proofs, and manage your proof library. Sign in directly from TimeAnchor to verify your proofs.
Learn more →SignaSeal
Digital signature and document verification platform. Combines signatures with timestamps for complete document integrity.
Coming soonThe Trust Problem We Solve
When you share a timestamped document with a lawyer, auditor, or counterparty, they shouldn't have to trust you or us. TimeAnchor provides independent verification — they upload their copy of the file, and we verify it against the blockchain. Three-point verification: their file, our records, the blockchain. All must match.
ProveChain Integration
If you use ProveChain to timestamp your documents, you can verify them directly from TimeAnchor without needing to handle proof files yourself.
Sign In & Verify
Sign in with your Aramantos account on the ProveChain tab. Your proofs are loaded automatically. Select one, several, or all proofs and verify them against Bitcoin in batch.
Share Links
ProveChain lets you create share links for any proof. Anyone with the link can verify it on TimeAnchor — no account needed. Share links support both view-only verification and full file-upload verification.
The Triangle of Proof
The strongest verification connects three independent points:
- 1.Your file — the original document you want to prove existed
- 2.ProveChain — the stored hash and metadata from when it was timestamped
- 3.Bitcoin — the immutable blockchain record that anchors the timestamp
When you verify using a share link with file upload, all three points are checked. Your file's hash must match ProveChain's stored hash, and that hash must be confirmed on Bitcoin. If any point doesn't match, the verification fails.
Folder Verification
TimeAnchor can verify entire folders, not just individual files. This is essential for proving the state of a project, codebase, or document collection at a specific point in time.
Hash Each File
Every file in the folder is individually hashed using SHA-256. Each file produces a unique fingerprint.
Build a Hash List
The file path and hash for each file are combined into sorted path:hash entries. This ensures the same folder always produces the same result, regardless of file system ordering.
Compute the Folder Hash
The sorted entries are joined and hashed again, producing a single SHA-256 hash that represents the entire folder. This is the hash that gets anchored to the blockchain.
Verify the Whole Folder
To verify, the same process is repeated on your folder. If even one file has changed, been added, or been removed, the folder hash will be different and verification will fail.
The folder hashing algorithm is open source in the TimeAnchor repository for full transparency.
Technical Details
| Hash Algorithm | SHA-256 (computed client-side) |
| Supported Blockchains | Bitcoin (via OpenTimestamps), Ethereum, Polygon, Arbitrum, Optimism |
| File Privacy | Your document never leaves your browser. Only the hash is used for verification. |
| Verification Methods | OTS calendar servers (Bitcoin), transaction input data & event logs (EVM chains), ProveChain API (direct integration) |
| Folder Support | Files & folders — folder hashes computed from sorted path:hash entries (SHA-256) |
| Cost | Free forever. Verification is a public good. |