About HMAC Cryptographic Signature Generator
Generate Hash-based Message Authentication Codes (HMAC) for webhook verification, API authentication, and JWT signing. Supports SHA-256, SHA-512, SHA-384, and SHA-1 in Hex or Base64.
Key Capabilities & Features
- Supports HMAC-SHA256, HMAC-SHA512, HMAC-SHA384, HMAC-SHA1
- Hexadecimal and Base64 output digests
- Hardware-accelerated Web Crypto API execution
- 1-Click copy signature
How to Use HMAC Cryptographic Signature Generator
Select Algorithm
Pick SHA-256 (standard) or SHA-512.
Enter Secret Key & Message
Provide your secret key string and payload message.
Compute & Copy
Click Compute HMAC Signature and copy the digest.
Privacy & In-Browser Execution Guarantee
HMAC calculation is executed locally via the Web Crypto API. Secret keys never leave your device.
Frequently Asked Questions
What is an HMAC?
An HMAC (Hash-based Message Authentication Code) combines a secret cryptographic key with message data to verify both data integrity and the authentic identity of the sender.
How does HMAC prevent replay and tampering attacks?
Because an attacker lacks the private secret key, any modification to the payload invalidates the signature, preventing unauthorized tampering.
Where are HMAC signatures used in industry?
HMAC-SHA256 is the standard for webhook verification (Stripe, GitHub, Shopify), AWS Signature Version 4, and JWT (JSON Web Token) HS256 tokens.