Hash

What is Hash?

A hash is a unique digital fingerprint created by running data through a mathematical function. It transforms any inputfrom a single character to an entire databaseinto a fixed-length string of characters that is virtually impossible to reverse.

How does Hash work?

1. Input data of any size is provided to a hash function.
2. The function perform a series of bitwise operations and transformations.
3. A fixed-size output (the hash) is generated.
4. Any change to the input, however small, produces a radically different hash.
5. The function is one-way: you can generate a hash from data, but not data from a hash.

Why does Hash matter?

Hashes are fundamental to blockchain integrity because they allow the network to verify that data has not been tampered with. Each block in a chain contains the hash of the previous block, creating an unbreakable cryptographic link.

Key features of Hash

• Deterministic (same input always equals same output)
• Fixed output length regardless of input size
• Highly sensitive to input changes ("Avalanche Effect")
• Computationally efficient to generate
• Collision-resistant (unique inputs produce unique outputs)

Examples of Hash

A Bitcoin transaction hash (TXID) uniquely identifies a specific transfer, while a block hash identifies an entire collection of transactions and the state of the network at a specific point in time.