HMAC generator

Computed in your browser using the Web Crypto API.

What is HMAC generator?

An HMAC (Hash-based Message Authentication Code) proves both that a message hasn't been tampered with AND that it came from someone who knows a shared secret key — a plain hash alone can't prove the second part, since anyone can hash a message.

How to use it

Enter a message and a secret key, and pick the underlying hash algorithm. This is exactly how webhook signature verification works (Stripe, GitHub, etc. all sign payloads this way).

Example

Message: "The quick brown fox", Key: "my-secret-key", HMAC-SHA256: cc3f378ba5084cb4c800968b7fb2bcc23ad61f003333220f417fb2171048013a