🔐 W3C Web Cryptography API Engine (RFC 2104)
HMAC Generator
Compute secure Hash-based Message Authentication Codes (HMAC-SHA256, HMAC-SHA512) client-side with 100% private in-browser hashing.
Hexadecimal HMAC Signature
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Base64 Encoded Signature
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RFC 2104 HMAC Architecture
An HMAC is defined mathematically by:
HMAC(K, m) = H((K' ⊕ opad) ∥ H((K' ⊕ ipad) ∥ m))
Where $H$ is a cryptographic hash function, $K'$ is the normalized key, $ipad$ is the inner padding byte ($0\text{x}36$), and $opad$ is the outer padding byte ($0\text{x}5C$).