Hash
Hash (Cryptographic Digest)
A fixed-length string of characters generated by a mathematical function from any input data, serving as a unique fingerprint. Even a tiny change in the input produces a completely different hash value.
技術的詳細
Cryptographic hash functions (SHA-256, SHA-3, BLAKE3) must satisfy three properties: preimage resistance (cannot reverse to find input), second preimage resistance (cannot find another input producing the same hash), and collision resistance (cannot find any two inputs with the same hash). Non-cryptographic hashes (CRC32, MurmurHash, xxHash) prioritize speed over security for checksums and hash tables. In web applications, the SubtleCrypto API provides browser-native SHA-1/256/384/512 hashing. Content-addressable storage systems (Git, IPFS) use hashes as identifiers.
例
```javascript
// Hash: web API example
const response = await fetch('/api/resource');
const data = await response.json();
console.log(data);
```