In this track: Trees, roots and proofs
Why a trusted root matters
A proof is only as relevant as the root it is checked against.
A route to an arbitrary building does not prove you reached the authorized office.
This example hashes UTF-8 A, B, C and D. The displayed hashes are abbreviated, and the tree uses the playground’s sorted-pair convention.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
Separate consistency from authority
A proof can be mathematically consistent with a tree an attacker created. That says nothing about whether the application intended to accept that tree.
Obtain the root through the protocol
An allowlist contract may store an authorized root. A chain proof needs an appropriately authenticated block context and root. The trust source must be explicit.
Check update permissions
If a privileged actor can change the accepted root, that authority affects the security model. A proof does not remove the risk of an unauthorized or malicious root update.
Describe the claim narrowly
A membership proof shows inclusion of an encoded value under the accepted construction. It does not independently prove honesty, asset backing or the correctness of every input record.
Follow the proof model
Convention: UTF-8 leaves, Keccak-256, lexicographically sorted hash pairs
leaf A: 0x03783fac2efed8fbc9ad443e592ee30e61d65f471140c10ca155e937b435b760
sibling B: 0x1f675bff07515f5df96737194ea945c36c41e7b4fcef307b7cd4d0e602a69111
parent AB: 0x69de756fea16daddbbdccf85c849315f51c0b50d111e3d2063cab451803324a0
sibling parent CD: 0xe62e1dfc08d58fd144947903447473a090c958fe34e2425d578237fcdf1ab5a4
root: 0x4e2b32e9c7b10ee15f38192ed65b95656a84e32531157b9384ef0d3cabe95956Binary examples use the stated local playground convention. They are not Ethereum account or storage trie proofs.
Does a proof against an attacker-selected root establish authorized membership?
The root must be accepted under the intended trust model.
Original explanations by EtherTools. Examples are educational and source-linked; this site is independent of the Ethereum Foundation. Our approach.