HMAC Generator
Generate an HMAC (hash-based message authentication code) for any message and secret key using SHA-256, SHA-384 or SHA-512. Unlike a plain hash, an HMAC mixes in a secret key, so it both fingerprints the message and proves it was produced by someone who knows the key. That is why HMACs sign webhooks, API requests and tokens: the receiver recomputes the HMAC with the shared secret and checks that it matches. This tool uses your browser native Web Crypto API to compute the code and shows it as a lowercase hex string. Enter your message, your secret and pick an algorithm, then click generate. Everything runs locally in your browser, so your secret key is never transmitted to any server.
How to use HMAC Generator
- Enter your message.
- Enter the secret key.
- Choose SHA-256, SHA-384 or SHA-512.
- Copy the hex HMAC output.
Frequently asked questions
What is an HMAC?
An HMAC is a keyed hash that combines a secret key with your message using a hash function, producing a signature that proves the message came from someone holding the key.
Which hash functions are available?
You can compute the HMAC with SHA-256, SHA-384 or SHA-512 via the Web Crypto API.
How does HMAC differ from a plain hash?
A plain hash uses only the message, while an HMAC also mixes in a secret key, so it can authenticate the message and not just fingerprint it.
What is HMAC Generator?
Generate an HMAC (hash-based message authentication code) for any message and secret key using SHA-256, SHA-384 or SHA-512. Unlike a plain hash, an HMAC mixes in a secret key, so it both fingerprints the message and proves it was produced by someone who knows the key.
Is HMAC Generator free to use?
Yes. HMAC Generator is completely free, with no sign-up and no usage limits.
Does HMAC Generator work in a web browser?
Yes. HMAC Generator runs in any modern web browser. There is nothing to download or install.
Is my data private with HMAC Generator?
Yes. HMAC Generator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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