How is the HMAC computed?

Using your browser's native Web Crypto API (crypto.subtle), which securely signs the message with your key using the selected hash algorithm.

Is my secret key sent anywhere?

No, everything is computed locally in your browser — your key and message are never transmitted.

What's the difference between HMAC and a plain hash?

A plain hash has no secret key, so anyone can compute it. An HMAC combines a secret key with the message, letting you verify both integrity and authenticity.

Which hash algorithms can I use for the HMAC?

HMAC can be computed with SHA-1, SHA-256, SHA-384, or SHA-512 as the underlying hash function, matching what's available in the Web Crypto API.

Why would I use HMAC instead of just hashing the message?

A plain hash proves the message wasn't altered but anyone can compute it; HMAC also requires knowledge of a shared secret key, so it proves the message came from someone who holds that key.

How do I verify a signature I received?

Paste the HMAC into Verify a signature (hex, Base64 or Base64URL). The tool compares it to the one it computes for your message and key and tells you whether they match.

Can I use a hex or binary key?

Tick Key is hex to enter the key as pairs of hex digits instead of plain text.

Processed 100% locally in your browser

HMAC Keyed-Hash Generator

Generate an HMAC in hex or Base64 and verify a received signature, computed locally in your browser.

Quick Answer

HMAC Keyed-Hash Generator lets you: Generate an HMAC in hex or Base64 and verify a received signature, computed locally in your browser. To start, type or paste the message you want to sign.

Loading tool…

How to use this tool

1
Enter your message
Type or paste the message you want to sign.
2
Enter your secret key
Type the secret key used to compute the HMAC.
3
Choose an algorithm
Select SHA-1, SHA-256, SHA-384, or SHA-512.
4
Copy the HMAC
The resulting hex-encoded HMAC updates instantly — copy it with one click.

Frequently Asked Questions

Hash Generator

Generate MD5, SHA and CRC32 hashes of text or files and verify a checksum — processed 100% locally.

Password Generator

Create strong passwords and passphrases with live entropy and crack-time estimates — generated securely in your browser and never stored.

HMAC Keyed-Hash Generator

How to use this tool

Enter your message

Enter your secret key

Choose an algorithm

Copy the HMAC

Frequently Asked Questions

How is the HMAC computed?

Is my secret key sent anywhere?

What's the difference between HMAC and a plain hash?

Which hash algorithms can I use for the HMAC?

Why would I use HMAC instead of just hashing the message?

How do I verify a signature I received?

Can I use a hex or binary key?

Related Tools

Hash Generator

Password Generator

HMAC Keyed-Hash Generator

How to use this tool

Enter your message

Enter your secret key

Choose an algorithm

Copy the HMAC

Frequently Asked Questions

How is the HMAC computed?

Is my secret key sent anywhere?

What's the difference between HMAC and a plain hash?

Which hash algorithms can I use for the HMAC?

Why would I use HMAC instead of just hashing the message?

How do I verify a signature I received?

Can I use a hex or binary key?

Related Tools

Hash Generator

Password Generator