Question 1

What is a cryptographic hash?

Accepted Answer

A cryptographic hash function takes an input (text, file, etc.) and produces a fixed-size string of bytes that appears random. The same input always produces the same hash (deterministic), but even a tiny change in input produces a completely different hash (avalanche effect). Hashes are used for data integrity verification, password storage, digital signatures, and commit identifiers (Git).

Question 2

Which should I use: MD5, SHA-1, SHA-256, or SHA-512?

Accepted Answer

For security purposes, use SHA-256 or SHA-512. MD5 and SHA-1 are considered cryptographically broken and should not be used for security. However, MD5 is still useful for checksums and non-security purposes. SHA-256 offers a good balance of security and output length for most applications.

Question 3

Where is hash generation done — on a server or in my browser?

Accepted Answer

All hash generation happens entirely in your browser using the Web Crypto API (SubtleCrypto) for SHA algorithms and a JavaScript implementation for MD5. Your input text never leaves your device. You can verify this by disconnecting your internet — the tool continues to work.

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