HMAC Generator

Generate cryptographic hash-based message authentication codes (HMAC) instantly.

Message (String)

Secret Key

Output Format

Generated Hashes

HMAC SHA256

HMAC SHA512

HMAC SHA384

HMAC SHA1

HMAC MD5

HMAC RIPEMD160

HMAC Explained

Hash-based message authentication code (HMAC) involves a cryptographic hash function and a secret cryptographic key.

It verifies both the data integrity and the authentication of a message.
Any change to the message or the secret key will result in a completely different hash.
It prevents length extension attacks, a common vulnerability in simple hashing.

What is HMAC?

HMAC stands for Hash-based Message Authentication Code. It is a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. It may be used to simultaneously verify both the data integrity and the authentication of a message.

How is it used?

HMACs are widely used in web applications, especially for API authentication (like AWS Signature, Webhooks, JWTs). The sender and receiver both share a secret key. The sender hashes the message with the key and sends both the message and the hash. The receiver re-hashes the message with their copy of the key and verifies that the output matches the sent hash.

Privacy Note

All calculations are performed locally in your browser. Your message and your secret key are never sent to our servers.

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