How are blocks linked?

Each new block points to the fingerprint of its parent.

LET’S PICTURE IT

Imagine each notebook page starts by copying a fingerprint of the previous page. Editing the previous page makes that reference stop matching.

SEE IT FOR YOURSELF

Link blocks, then see what an edit breaksStep 1 / 4

The first toy block records Maya sending Leo three units. A1 is an illustrative fingerprint label, not a real cryptographic digest.

Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.

Hashes connect pages

A hash is a result calculated from bytes. A block refers to its parent using the parent’s hash. Nodes use that reference to understand which earlier state the new block builds on.

Edits become visible

Change data covered by a hash and the calculated hash will almost certainly change. The next block still points to the old hash, so the link no longer describes the edited version. Try changing the first page in the experiment.

Rebuilding links is not enough

On your own computer, you can edit a toy chain and calculate new hashes for every later page. That does not make other Ethereum nodes accept your edited history. They enforce consensus rules and state-transition validity as well.

The connection has a limit

Hash linking helps detect changed data and identify ancestry. It does not prove that an external statement was truthful. If someone writes a false claim about a real-world object, a hash only commits to the bytes of that claim.

QUICK CHECK · NO PRESSURE

Can recalculating toy hashes alone rewrite Ethereum’s accepted history?

Your progress stays in this browser.

Keep exploring the original referenceethereum.org ↗

Original explanations by EtherTools. Examples are educational and source-linked; this site is independent of the Ethereum Foundation. Our approach.