Limits

We would rather you trust the maths than trust us, so here is exactly what a stamp does and does not mean.

What a stamp proves

• That a file with this exact fingerprint existed no later than the stated time, because its fingerprint was committed to two blockchains.

What it does not prove

• Who created the file, or that anyone in particular held it.
• That the file's contents are true, lawful, or original.
• That the file existed any earlier than the stamp — only that it existed by then.

Practical notes

• Only the fingerprint leaves your device. Keep your own copy of the file; we cannot restore it.
• Do not stamp tiny, guessable files.
• Block times can drift by up to about two hours; the receipt uses the conservative time.

Public beta — nothing is charged during the beta, and how we handle your data is set out in Privacy before you use the service.