About HMAC Generator
HMAC tool generates keyed message authentication codes with SHA-256, SHA-512 and other digest algorithms. Useful for API signatures, webhook verification, tamper protection and integration debugging.
How to Use
- Enter the message to sign
- Provide the shared secret key
- Select HMAC algorithm and output encoding
- Copy the generated signature for API verification
Frequently Asked Questions
- How is HMAC different from a regular hash?
- A regular hash has no secret. HMAC uses a shared key, so it verifies both message integrity and that the sender knows the key.
- Why does my API signature not match?
- Common causes include parameter order, newlines, encoding, timestamp, key or algorithm mismatch. Build the string-to-sign exactly as the API document requires.
- Can HMAC decrypt data?
- No. HMAC is an authentication code, not encryption. It verifies integrity and origin but cannot recover plaintext.