🔏 HMAC SHA-256
Compute HMAC SHA-256 of a message with a secret key.
HMAC
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How it works
How it works
HMAC (Hash‑based Message Authentication Code) uses a cryptographic hash (SHA‑256) together with a secret key to authenticate messages.
- The key is normalized to the hash block size and combined with inner/outer pads (
ipad/opad). - Compute
H(key ⊕ opad || H(key ⊕ ipad || message)), whereHis SHA‑256. - Verification recomputes the same MAC and compares in constant time.
Use‑cases: API request signing, webhooks, and integrity/authentication of messages between parties sharing a secret.
Privacy & Security
Secret never leaves browser.
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Accuracy, Limits & Tips
No streaming; loads whole message into memory.
Examples
- Key: secret, Message: hello world.
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Looking for broader guides and best practices? Visit the ToolsAreUs Blog for indexes (like the full tool list) and articles (e.g. secure password generation).