Tool Fu
$ toolfu run hmac-generator

HMAC Generator — Generate HMAC-SHA256 / SHA512 Online Free

Generate HMAC digests using SHA-256, SHA-512, SHA-384, and SHA-1. Free online HMAC generator using the Web Crypto API — your secret key never leaves your browser.

all processing runs in your browser
hmac-generator
input > message
secret > key
algorithm

Free Online HMAC Generator

Generate HMAC (Hash-based Message Authentication Code) digests instantly. Enter a message and secret key to get HMAC-SHA256, HMAC-SHA512, and other variants.

Features

  • SHA-256, SHA-512, SHA-384, SHA-1 algorithms
  • All digests generated simultaneously
  • Uses the Web Crypto API for security
  • Copy individual results to clipboard
  • 100% private — nothing sent to any server
$ cat FAQ.md
What is HMAC?
HMAC (Hash-based Message Authentication Code) is a cryptographic method that combines a hash function with a secret key to verify both the data integrity and authenticity of a message.
How is HMAC different from a regular hash?
A regular hash only uses the message as input, while HMAC also requires a secret key. This means only parties who know the key can generate or verify the HMAC, providing authentication in addition to integrity.
Which algorithm should I use?
SHA-256 is the most common choice, offering a good balance of security and performance. SHA-512 provides stronger security. SHA-1 is considered legacy and should be avoided for new applications.
Is my secret key safe?
Yes. HMAC generation uses the Web Crypto API and runs entirely in your browser. Your secret key and message never leave your device.