HMAC Generator — HMAC (Hash-based Message Authentication Code, RFC 2104) is the standard way to verify both the integrity and authenticity of a message. Given a message and a shared secret, it produces a fixed-size tag that only the holder of the same secret can recompute.
Computation runs entirely in your browser. Your message and secret never leave this device.
Was HMAC Generator useful?
What is hmac generator?
HMAC (Hash-based Message Authentication Code, RFC 2104) is the standard way to verify both the integrity and authenticity of a message. Given a message and a shared secret, it produces a fixed-size tag that only the holder of the same secret can recompute.
This tool uses the RFC 2104 algorithm directly (no library magic) and outputs the MAC in hex. All computation runs in your browser, so even sensitive secrets never leave the device.
How to use it
-
Pick an algorithm
SHA-256 is the modern default. SHA-1 / MD5 are kept for compatibility with legacy systems; do not use them for new work.
-
Enter the secret and message
Secrets can be plain text or a hex string prefixed with "hex:". Messages are plain UTF-8 text.
-
Copy the hex MAC
Use the hex output directly in HMAC headers (e.g. X-Hub-Signature-256) or as a binary comparison key.
Preguntas frecuentes
Herramientas relacionadas
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes of any text instantly.
JWT Sign (HS256 / RS256)
Sign a JSON Web Token with HS256 (HMAC shared secret) or RS256 (RSA private key). Output is a standard compact JWT (header.payload.signature).
Signature Maker
Draw a handwritten signature in your browser with mouse, trackpad, or touch. Pick a pen color, set the stroke width, and download the result as a transparent PNG. Free, no upload.
Last reviewed: 2026-09-24