HMAC-SHA Message Authenticator (256/512/1)
Processed in your browser
Compute cryptographic Hash-based Message Authentication Codes (HMAC-SHA256, HMAC-SHA512, HMAC-SHA1) in Hex and Base64.
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Direct In-Browser Handoff
Cryptographic Hash & Integrity Pipeline
Chain this tool with complementary private browser utilities for a complete zero-server workflow:
Helpful Examples
HMAC-SHA256 Test
Authenticate payload with secret
Key: secret123, Message: Hello WorldHow to Use the HMAC-SHA Message Authenticator (256/512/1)
Generate secure HMAC message authentication digests using Web Crypto API. Test API secret signatures, webhook verifications, and AWS/GitHub signature headers with secret keys.
Privacy & Data Processing Notice
No user data leaves your browser. Computation is executed entirely on your device. We do not store, view, or transmit your inputs over our network. Your computation remains on your personal machine.
Frequently Asked Questions
How does HMAC differ from a regular hash?
A standard SHA hash only verifies data integrity. An HMAC combines the message with a shared secret key, proving both integrity and authenticity (only the holder of the key could have generated it).
Can this be used to verify webhooks (e.g., GitHub, Stripe)?
Yes. Paste the payload and secret key into the calculator to verify if your computed HMAC matches the webhook header.
Related Utilities
Frequently paired browser tools in Encoding, Hashing & Cryptography