Security — Dev Tool
HMAC Generator
Runs entirely in your browser · Nothing is sent to our servers
Generate HMAC-SHA256 or HMAC-SHA512 message authentication codes with a secret key.
Algorithm
Format
HMAC Output
What is HMAC?
HMAC (Hash-based Message Authentication Code) combines a cryptographic hash function with a secret key to produce a unique signature for a message.
HMAC vs plain hash
A plain hash like SHA-256 proves a message has not changed. HMAC goes further — it also proves the sender knew the secret key. Without the key, the signature cannot be reproduced even if the message is known.
Common uses
- ‣ Signing API requests (AWS, Stripe, GitHub)
- ‣ Verifying webhook payloads
- ‣ Protecting cookie and session integrity
- ‣ Message authentication between services
About HMAC▾
What is HMAC?
HMAC (Hash-based Message Authentication Code) combines a cryptographic hash function with a secret key to produce a unique signature for a message.
HMAC vs plain hash
A plain hash like SHA-256 proves a message has not changed. HMAC goes further — it also proves the sender knew the secret key. Without the key, the signature cannot be reproduced even if the message is known.
Common uses
- ‣ Signing API requests (AWS, Stripe, GitHub)
- ‣ Verifying webhook payloads
- ‣ Protecting cookie and session integrity
- ‣ Message authentication between services