What is a cryptographic hash?
A cryptographic hash function turns input of any length into a fixed-length fingerprint. The same input always gives the same hash, and changing even one character gives a completely different one. Hashes are used to verify file and download integrity, compare data without storing it, build cache keys, and inside signatures and protocols. This tool hashes the UTF-8 bytes of your text using your browser's built-in Web Crypto API and shows the result as hexadecimal.
Hashing vs encryption
Hashing is one-way: there is no key and no way to turn a hash back into the original text. Encryption is two-way: data encrypted with a key can be decrypted with the right key. A hash is not encryption, so don't use it to "hide" data you need to read back later.
SHA-256 example
The SHA-256 hash of hello world is b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9. Note that whitespace matters: a trailing newline or a Windows line ending (\r\n) produces a different hash.
Security note
- SHA-1 is considered cryptographically weak and should not be used for security-sensitive purposes. Prefer SHA-256 or stronger.
- Do not use simple SHA hashes for password storage. Fast hashes can be brute-forced quickly; passwords need a slow, salted algorithm such as Argon2, scrypt, or bcrypt, run on your server.
- MD5 is intentionally not offered: it is broken and not supported by Web Crypto.
FAQ
Is my text uploaded?
No. Hashing runs locally with your browser's Web Crypto API.
Why doesn't my hash match the one from another tool?
Usually the input differs invisibly — a trailing newline (common with echo; use printf instead), different line endings, or a different text encoding. This tool always hashes UTF-8.