Fingerprint your files now. Show later that they haven’t changed.
Witness reads files on this device and computes a SHA-256 fingerprint of each one. The fingerprints go into a single record identified by its Core ID. File contents and names never leave this device. If you ask for timestamps, only a 32-byte fingerprint of the Core ID is sent.
Create a record
Choose the files to fingerprint
Photos, video, audio, documents: any file. Up to 1,000 per record.
Independent timestamps (optional)
Two independent timestamp services, DigiCert and Sectigo, each sign that this record existed no later than now. Only a 32-byte fingerprint of the Core ID is sent, through this website. No file, file name or record leaves this device.
What to keep
- The original files, unchanged. The record holds fingerprints, not copies.
- The record file (
.hashit). Anyone can check files against it on the Check page. - The timestamps file (
.anchors), if you got one. It shows the record existed no later than the time the two services signed. - The Core ID, somewhere dated that you do not control alone, such as an email to another person.
Fingerprints in this record
Each fingerprint is the file’s SHA-256 in hex, the same value shasum -a 256 prints. File names are shown here only; the record contains fingerprints and sizes, not names.
What a record can and can’t show
It shows
- Whether a file is byte-for-byte identical to one that was fingerprinted. Change one pixel and it no longer matches.
- Whether the record itself has been altered, when you compare it with a Core ID you kept separately.
- With timestamps: that the record existed no later than a given time, according to two independent services.
It does not show
- When the files were made. A timestamp shows only that the record existed by then.
- Who made it. This version is not signed yet.
- That the content is accurate, or how a court will treat it.