KPP · BlockDAG · PoW · Immutable

Proof of existence
on Kaspa

Permanently timestamp any file on the Kaspa BlockDAG. No accounts. No uploads. No trust. Cryptographically verifiable.

Stamp a file →
1s
First confirm
3 KAS
Per stamp
Forever
On-chain
Proof of ExistenceSHA-256Kaspa BlockDAGUnforgeableNo UploadsClient-side OnlyPrivacy FirstKPP-1 ProtocolImmutableHash-derived AddressesNo CertificatesTransaction History Proof of ExistenceSHA-256Kaspa BlockDAGUnforgeableNo UploadsClient-side OnlyPrivacy FirstKPP-1 ProtocolImmutableHash-derived AddressesNo CertificatesTransaction History
The mechanism

How it works

Three steps. No middlemen. Your file never leaves your device. Only its mathematical fingerprint touches the blockchain.

01
🔐
Hash
Your file is SHA-256 hashed locally in your browser. The hash is a unique fingerprint. Change one byte and the entire hash changes. Your file is never uploaded anywhere.
02
⛏
Stamp
The hash becomes a Kaspa address through deterministic key derivation. A stamp transaction is sent: 2 KAS to miners, 1 KAS protocol fee, 0.2 KAS proof deposit (auto-returned). Net cost: 3 KAS. The timestamp is set by the Kaspa network, not by you.
03
🔍
Verify
Anyone can drop the same file, derive the same address, and check if it has transactions. If yes, the file was stamped. The date is permanent and unforgeable.
Getting started

How to use it

Six steps. Two minutes. Permanent proof.

01
🌐
Open KasProof
Go to kasproof.com. Your browser generates a wallet automatically. No extension, no account, no signup.
02
🔑
Backup your key
Click "Backup key" and save it somewhere safe. This is YOUR wallet. Your key lives in your browser storage. Private browsing, clearing cookies, or switching browsers creates a new wallet. Your old KAS stays in the old wallet and is only recoverable with the key. Back up BEFORE sending any funds.
03
💰
Fund your wallet
Send 5 to 10 KAS to the wallet address shown on the page. That is enough for few stamps. Only send what you need.
04
📄
Drop your file
Drop any file in the Stamp tab. Image, document, video, contract, code. Your file is hashed locally and never leaves your device.
05
⛏
Stamp it
Click Stamp. One transaction. 3 KAS. Your file now has a permanent, unforgeable timestamp on the Kaspa DAG.
06
🔍
Verify anytime
Drop the same file in the Verify tab. Same file means verified. A modified file fails verification. Anyone can verify, no receipt needed.
Protect your wallet. Your key is stored in your browser. Private or incognito browsing, clearing cookies, or switching browsers means a new wallet is generated and your old KAS stays in the old wallet. Always backup your key first. You can restore on any device with "Restore key."
The tool

Stamp & Verify

Drop a file. Get permanent proof on the Kaspa BlockDAG. Or verify any file. No receipt needed, the chain is the proof.

One file. One hash. One address.

Every file produces a unique SHA-256 hash. That hash becomes a unique Kaspa address. Sending any transaction to that address is your timestamp, permanently recorded on the BlockDAG.

Verification works in reverse: hash the file, derive the address, check if a transaction exists. That timestamp is your proof.

Your file never leaves your browser. Only the hash touches the chain.

STAMP
VERIFY
📄
Drop any file to stamp
image, document, contract, anything
🔍
Drop any file to verify
no certificate needed. The chain is the proof
What it proves

Trustless proof

Two parties. One file. Both can verify. Neither can tamper. The DAG is the witness.

✓ Immutable proof

  • This exact file existed no later than this date
  • Not a single byte has been modified since stamping
  • The timestamp was set by the Kaspa network. Nobody can backdate it
  • Both parties can independently verify the same document
  • Neither party can alter the file without breaking verification

✓ Real-world use

  • Stamp a signed contract so both sides hold the same unbreakable proof
  • Prove your song, design, or code existed before anyone else claims it
  • Timestamp an agreement so both parties hold the same verifiable record
  • Timestamp evidence, legal documents, or any file that must never change
  • Share a document knowing any tampering is instantly detectable
Trust model

Security & privacy

No servers. No uploads. No accounts. Every critical operation happens locally in your browser.

🔐

Client-side hashing

Your file is hashed with SHA-256 in the browser via the Web Crypto API. The file never leaves your device. Not even a byte.

🧮

Deterministic derivation

File hash → private key → Kaspa address. Same file always produces the same address. Different file = different address. Pure math.

📡

Transaction history

Verification checks the permanent transaction history via the Kaspa REST API, not just the current balance. Proof survives even if the proof deposit is spent.

⚡

Adaptive fees

If the network is busy, the priority fee bumps automatically. Stamps don't fail during high traffic, they just cost a fraction more.

👁️

Zero personal data

No accounts. No emails. No tracking. No analytics. The wallet key lives in your browser's localStorage. Nowhere else.

🛡️

Hardened codebase

XSS-sanitized logs. Timeout-protected API calls. File size guards. Response validation. Open source. Review every line.