HMAC Generator

About the HMAC Generator

HMAC (Hash-based Message Authentication Code) is a type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. It's used to simultaneously verify both the data integrity and the authenticity of a message. This tool allows you to generate HMACs using various hash algorithms (SHA-256/384/512, SHA3 series) and a user-provided secret key.

Why Use This Tool?

HMACs are crucial for: ensuring that messages haven't been tampered with during transmission (integrity); and verifying that a message originates from a party possessing the secret key (authenticity). It's widely used in API authentication (e.g., AWS signatures, JWT HS* algorithms), secure communication protocols, and data verification.

Example Use Cases

• Generating an HMAC-SHA256 signature for an API request to authenticate the client.
• Verifying an HMAC received with a webhook payload to ensure its authenticity and integrity.
• Creating a keyed hash for data validation where both integrity and source authentication are important.

Pro Tips

• Secret Key Security: The security of HMAC relies heavily on the secrecy of the key. Keep your secret keys confidential and use cryptographically strong keys.
• Key Format: Pay attention to the 'Key Format' if your key is not a simple UTF-8 string. If your key is in Hex or Base64, select the appropriate format so it's correctly converted to bytes before being used in the HMAC calculation.