HMAC Calculator
Compute a keyed message authentication code (HMAC) to verify integrity and authenticity.
Hashing & encryption Client-side WebCrypto HMAC
Tool preview
How to use it
- 01
Enter the message.
- 02
Enter the secret key.
- 03
Choose the hash and compute.
Limitations
- ! The key is typed in plain text on screen; avoid using production secrets on a shared machine.
- ! Only HMAC-SHA1, SHA-256 and SHA-512 are offered.
FAQ
How is HMAC different from a plain hash?
HMAC mixes in a secret key, so only someone holding the key can produce a valid tag.
Is HMAC encryption?
No, the message stays readable; HMAC only proves it was not altered by someone without the key.
Is the key sent anywhere?
No, the computation runs in the page.
Files never leave your device
Processing happens in your browser using the File API, WebAssembly and Web Workers. There is no upload endpoint.
Technical details
- Processing
- Client-side
- Implementation
- WebCrypto HMAC
- Category
- Hashing & encryption
- Network requests
- None while processing