Choose how to ProofStamp a file.
Your file is fingerprinted on your device with SHA-256. Choose how you want to preserve that fingerprint so it can be checked later.
ProofStamp via Email
Everyday evidence
Create a portable ProofStamp and keep it in an email or saved receipt.
- No account
- No wallet
- Files stay on your device
nStamp
Public blockchain timestamp
Anchor your file fingerprint to NEAR and keep a public transaction record.
- Public blockchain record
- Fast on-chain timestamp
- Independently inspectable
ProofStamp via Bitcoin
Portable OpenTimestamps proof
Create a standard .ots proof that can later be upgraded and independently verified against Bitcoin.
- No wallet required
- Standard .ots proof
- Portable verification
ProofStamp via Arbitrum
Seamless web3 experience
Create an EAS ProofStamp on Arbitrum Sepolia using a passkey and sponsored transaction.
- No seed phrase
- No testnet ETH required
- On-chain EAS record
Not sure?
Start with ProofStamp via Email →
It is the simplest option for most everyday files.
Same file. Different proof paths.
The file stays with you. The method determines where its fingerprint is preserved.
A ProofStamp can help verify file integrity and, depending on the method, external time evidence. It does not by itself prove that the contents are true, who created them, or whether they were changed before they were ProofStamped.