HMAC Generator

About This Tool

The HMAC Generator creates Hash-based Message Authentication Codes — cryptographic signatures used to verify both message integrity and authenticity. HMAC combines a secret key with a hash function (MD5, SHA-1, SHA-256, SHA-512) to produce a unique signature.

HMAC is widely used in API authentication (AWS, Stripe), webhook signature verification, JWT signing, and secure data transmission protocols.

How to Use

1. Enter the message text you want to sign.
2. Enter your secret key (keep this confidential).
3. Select the hash algorithm (SHA-256 recommended for security).
4. The HMAC signature is generated instantly — copy it for use.

Use Cases

API request signing, webhook payload verification, session token generation, and any scenario requiring proof that a message was created by a specific sender.

FAQ

• What is HMAC? — HMAC (Hash-based Message Authentication Code) uses a secret key combined with a hash function to create a digital signature that proves message authenticity.
• Which algorithm should I use? — SHA-256 is the industry standard for most use cases. Avoid MD5 and SHA-1 for security-sensitive applications.
• Is the secret key sent anywhere? — No. All computation happens in your browser. Your key and message never leave your device.
• What is the difference between HMAC and a regular hash? — A regular hash (SHA-256) has no secret key — anyone can compute it. HMAC requires a shared secret key, making it impossible to forge without knowing the key.