Plain English
A hash is a cryptographic fingerprint of data. Any input — a file, a transaction, a block — produces a fixed-length string that uniquely identifies it. Change one character of the input and the hash changes completely.
How it actually works
Cryptographic hash functions (SHA-256 for Bitcoin, Keccak-256 for Ethereum) are one-way functions: easy to compute the hash from input, computationally infeasible to reverse. Hashes are what cryptographically link blocks together — each block contains the hash of the previous block, forming the chain.
What it means for you
Hashes are the math under “you cannot quietly change blockchain history.” When the curriculum says the ledger is tamper-evident, the hash chain is what makes it so.
Members do not need to compute hashes by hand. But understanding why a hash-chained ledger is structurally different from a database matters when you are explaining the strategy to your CPA or your heirs.
Educational content only. Not investment, tax, or legal advice.