Are my secret keys sent to a server?

HMAC Signature Generator

Security & Privacy

Cryptographically secure Hash-based Message Authentication Code (HMAC) generator. Compute HMAC-SHA256, HMAC-SHA512, and HMAC-SHA1 message signatures using the browser's native Web Crypto API with Hex and Base64 output.

100% Client-Side

HMAC Configuration

Secret Key:

Message / Payload:

Hexadecimal Signature (SHA-256)

Computing...

Base64 Signature (SHA-256)

Computing...

Zero-Knowledge Privacy Guarantee

This HMAC Signature Generator executes 100% locally in your browser’s JavaScript memory using client-side Web APIs. No inputs, keys, tokens, files, or outputs are ever uploaded to any server or logged in any database.

Key Features & Capabilities

Supports HMAC-SHA256, HMAC-SHA512, HMAC-SHA384, and HMAC-SHA1
Secret key encoding in UTF-8 Text or Raw Hex
Output in Hexadecimal and Base64 formats
100% private: Web Crypto API computes signatures in browser memory without sending keys

How to Use This Tool

1Enter your payload or message text.
2Enter your secret key.
3Select your HMAC hash algorithm (e.g. SHA-256).
4Copy the resulting Hex or Base64 signature.

Frequently Asked Questions (FAQ)

Never. The HMAC is calculated strictly using window.crypto.subtle in local browser memory.

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