Hash Generator

About this tool

A cryptographic hash function takes an input of any size — a word, a password, an entire file — and produces a fixed-length string of characters that acts as a fingerprint of that exact input. Change a single byte anywhere in the input and the resulting hash changes completely and unpredictably; the same input, hashed again, always produces the identical output. That combination of properties — deterministic, fixed-length, and wildly sensitive to any change in the input — is what makes hashing useful for integrity checks, deduplication, and (with important caveats) credential storage.

This tool generates four algorithms side by side so you can compare or pick the one a given task requires. MD5 and SHA-1 are older, fast, and still common in legacy systems and checksums, but both have known collision weaknesses — two different inputs can, with enough computation, be crafted to produce the same hash — which makes them unsuitable anywhere security actually depends on the hash being unforgeable. SHA-256 and SHA-512, from the SHA-2 family, have no known practical collision attacks and are the current standard for integrity verification, digital signatures, and blockchain applications; SHA-512 produces a longer digest and tends to be faster on 64-bit hardware, while SHA-256 remains the more commonly expected default in most tooling.

It's worth being precise about what hashing a password directly does and doesn't buy you, since this is the single most common point of confusion. Feeding a password straight through SHA-256 and storing the result is a large step up from storing it in plain text, but it's not what production authentication systems actually do — a bare hash of a password is still vulnerable to precomputed rainbow-table attacks and, for short or common passwords, brute force at speeds modern hardware makes uncomfortably fast. Real password storage uses purpose-built, deliberately slow algorithms — bcrypt, scrypt, or Argon2 — combined with a per-user random salt. This tool is for understanding and demonstrating what a hash is and does, and for the many hashing tasks that aren't password storage — it isn't a substitute for a proper password-hashing library in an application.

Where hashing does its most everyday work is integrity checking: downloading a large file and comparing its SHA-256 against the value the publisher listed, confirming a file wasn't corrupted or tampered with in transit, or detecting duplicate files in a large set without comparing their full contents byte for byte. All four algorithms here run using your browser's built-in cryptographic primitives (SubtleCrypto for SHA, a compact local implementation for MD5) — nothing you type or upload is transmitted anywhere.