Simple vs Actual Blockchain

Add blocks to both chains simultaneously. The Simple Chain links blocks using a short arithmetic formula. The Actual Chain uses real SHA-256 cryptographic hashes, the same method used in Bitcoin. Try tampering with a block to see how it breaks the chain. Once tampered, no new blocks can be added, just like in a real network, where peers reject a broken chain.

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Simple Chain - Arithmetic Link

Each block stores a link value computed as:
link = (prev_link × 31 + amount) mod 100,000

Fast and easy to verify mentally, but trivially forgeable; you can compute any value you want with the right inputs.

Actual Chain - SHA-256 Hash

Each block stores SHA-256(index + amount + prevHash + nonce). The hash is a 256-bit fingerprint; any change to any field produces a completely different hash, breaking the link to the next block.
Block states: Genesis Valid Tampered Broken (downstream)

Simple Chain

Actual Chain (SHA-256)