HMAC Generator
Compute a Hash-based Message Authentication Code (HMAC) for any message and shared secret. Supports SHA-256, SHA-512, SHA-1, and MD5. All computation runs in your browser.
Private: Your secret and message never leave this device. Pure client-side RFC 2104 HMAC.
Computation runs entirely in your browser. Your secret and message never leave this device.
Tip: prefix the secret with hex: if you have raw key bytes (e.g. hex:0b0b0b…).
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.