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Merkle Tree Visualizer — Real SHA-256, Real Tamper Detection

A real Merkle tree, built by hashing your data blocks pairwise bottom-up with real SHA-256 (via the browser's Web Crypto API) — the exact structure Bitcoin, Git and IPFS build their integrity trees from. Edit one leaf and watch exactly which path of hashes changes on the way to the root, while every sibling subtree not on that path stays byte-for-byte identical — then generate a real Merkle proof that verifies one leaf against the root using only a short hash path, not the entire dataset.

How to use Merkle Tree Visualizer

  1. Edit any data block (leaf).
  2. Watch which hash path changes, highlighted in amber.
  3. Notice untouched sibling subtrees stay identical.
  4. Pick a leaf and generate + verify its Merkle proof.

Frequently asked questions

Why does editing one leaf only change some of the hashes?
Only the parent hashes on the direct path from that leaf up to the root actually depend on its content — a sibling subtree that never contains the edited leaf hashes to exactly the same value as before, which is the property that keeps a Merkle proof short even for a huge dataset.
What is a Merkle proof actually proving?
That one specific piece of data is included in the dataset that produced a given root hash — verified using only that leaf plus a handful of sibling hashes along its path (logarithmic in the total leaf count), without needing the rest of the data at all.
Where is this actually used?
Bitcoin and other blockchains use Merkle roots to let a lightweight client verify a transaction is in a block without downloading the whole block; Git uses a similar hash-tree structure for commit integrity; IPFS and Certificate Transparency logs use it for tamper-evident data structures.
Is the SHA-256 real, or simulated for the demo?
Real — every hash is computed with the browser's native Web Crypto SHA-256 implementation, the same algorithm used in production systems, not a toy hash function standing in for it.

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