Verify a proof

Check if a document or hash has already been etched on Ethereum.

Direct hashPaste a SHA-256 hash directly — either from a single file or the session hash of a bundle (the sessionHash field in bundle_manifest.json).FileDrop a single file to compute its SHA-256 hash and check if it has been anchored on Ethereum.JSON proofDrop manifest.json (single file) or bundle_manifest.json (bundle) from your proof ZIP. The hash is extracted automatically.

Verify a file from a bundle

Individual file hashes are not anchored directly on Ethereum — only the bundle session hash is. Here is how to verify that a specific file was part of an anchored bundle.

Compute a file hash

Drop a file to compute its SHA-256

Nothing is uploaded. The hash is computed in your browser.

Compare with manifest

Drop bundle_manifest.json to compare

From the originals/ folder of your proof ZIP

Why this proves your file

1

The Ethereum blockchain records the session hash at a specific date. This is immutable — no one can change it.

2

The session hash is the SHA-256 of the bundle's file list (names, sizes, and individual hashes, sorted alphabetically). If the session hash is certified, the file list is certified too.

3

Each file's individual hash is in that certified list. If the list is certified, each hash it contains is certified.

4

A file's SHA-256 is a mathematical fingerprint — unique to that exact file. If the hash matches, the file is identical to what was anchored.

The chain: Ethereum → session hash → file list → individual hash → your file.

Open your proof ZIP and navigate to the originals/ folder to find your original files.