- 1Choose file
- 2Adjust
- 3Download
HMAC Generator & Calculator online, free
Compute Keyed-Hash Message Authentication Codes (HMAC) using secret keys across SHA-256, SHA-512, and SHA-1.
- Runs in your browser — no upload
- Free, no sign-up, no watermark
- TXT
How to use HMAC Generator & Calculator · HMAC Generator & Calculator — frequently asked questions
How to use HMAC Generator & Calculator
- 1
Add your TXT file
Drop a file on the page, paste it, or click Select Files. Nothing is uploaded — it opens straight in your browser.
- 2
Fine-tune the settings
Set hash algorithm in the Fine-tune panel, or keep the defaults — they suit most files.
- 3
Run HMAC Generator & Calculator
Press the start button. Processing happens on your device, usually in seconds.
- 4
Download the result
Save the finished file, or continue with another tool without downloading in between.
What HMAC Generator & Calculator can do
- Hash Algorithm: sha256, sha512 and sha1
- Private by design — files are processed in your browser and never uploaded
- Free with no sign-up, no watermark and no daily limit
HMAC Generator & Calculator — frequently asked questions
What is an HMAC?
An HMAC (Hash-based Message Authentication Code) is a cryptographic construction that uses a cryptographic hash function (like SHA-256 or SHA-512) and a shared secret key to verify both the data integrity and authenticity of a message.
Which hash algorithms are supported?
The tool supports HMAC-SHA256, HMAC-SHA512, and HMAC-SHA1 algorithms.
What is HMAC commonly used for?
HMAC signatures are ubiquitous in modern web APIs (such as AWS Signature v4, Stripe webhook verification, GitHub webhook payloads, and JWT signatures).
Is my secret key safe?
Yes. Because our tool executes 100% locally in your web browser using the Web Crypto API, your secret key and message are never sent over the internet or saved to any database.
Can I output uppercase hexadecimal signatures?
Yes. You can output signatures in standard lowercase hex or uppercase hex format.
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