Hash

A cryptographic function that maps arbitrary data to a fixed-size fingerprint — the cryptographic primitive enabling blockchain integrity.

Hash functions are deterministic (same input → same output), one-way (cannot reverse), and collision-resistant (hard to find two inputs with the same hash). Common algorithms include SHA-256 (Bitcoin) and Keccak-256 (Ethereum).

Systems Connection

Hashes create the causal links in blockchain structure. Each block contains the hash of its predecessor, forming a chain. This creates a feedback mechanism: any modification to a past block changes its hash, which invalidates all subsequent blocks. The boundary of valid history is enforced cryptographically.

Uses in Cryptoeconomics

• Block linking — chains blocks together
• Transaction IDs — unique identifiers for transactions
• Merkle trees — efficient verification of data inclusion
• Proof of work — mining puzzles based on hash difficulty

See Also

• Cryptoeconomics — parent domain
• Blockchain — structure built from hashes
• Consensus Mechanism — uses hashes for validation