Choose how to ProofStamp a file.
Your device creates a SHA-256 hash of the file. Choose how you want to keep or record that hash 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
They Told Me
Customer-service records
Preserve call recordings and chat screenshots in one portable ProofStamp with an independent timestamp.
- Files stay on your device
- No account
- Verify the saved proof later
nStamp
Public blockchain timestamp
Anchor your file hash 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
Passkey-based testnet proof
Create an EAS ProofStamp on Arbitrum Sepolia using a passkey and sponsored transaction.
- No seed phrase
- No testnet ETH required
- On-chain EAS record
ProofStamp via Solana
Sponsored public proof
Record your file hash on Solana devnet without connecting a wallet or paying gas.
- No wallet required
- Sponsored transaction
- Public Solana record
Not sure?
Start with ProofStamp via Email →
It is the simplest option for most everyday files.
Same principle. Different proof paths.
The file is hashed locally. Choose the proof path that fits what you need to preserve.
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.