Cryptographic Hash
security primitive
Cryptographic hashes are mathematical functions that convert input data of any size into a fixed-length output, known as a digest. These hashes are deterministic (same input always produces the same output), irreversible (original data cannot be derived), and collision-resistant (two inputs wonÔÇÖt generate the same hash). Hashes are essential in blockchain systems for linking blocks, validating data integrity, and powering cryptographic signatures and authentication protocols.
Use Case: A blockchain stores the hash of each blockÔÇÖs contents inside the next blockÔÇÖs header. If any part of the previous block is altered, its hash changes ÔÇö instantly signaling tampering and breaking the chainÔÇÖs integrity.
Key Concepts:
- Data Integrity ÔÇö Ensures stored or transmitted data hasn’t been modified
- Immutability ÔÇö Core to blockchainÔÇÖs unchangeable history
- SHA-256 ÔÇö A widely used cryptographic hashing algorithm
- Collision Resistance ÔÇö No two inputs create the same output
- Irreversible Encryption ÔÇö Hashes cannot be decrypted back to original data
- Digital Signatures ÔÇö Use hashes for fast message authentication
- Block Validation ÔÇö Every blockÔÇÖs hash depends on the previous
Summary: Cryptographic hashes are foundational to blockchain security and digital trust. They provide tamper detection, authentication, and structural integrity in decentralized systems by turning data into secure, fixed-length fingerprints.