HMAC Generator
Message Authentication
Generate cryptographic authentication codes to verify message authenticity and integrity using secret keys.
Secret Key Based
Uses shared secret keys for authentication, providing security against forgery attacks and unauthorized access.
HMAC Verification
Verify message authenticity by comparing generated HMACs with expected values to detect tampering.
Process Visualization
Understand the step-by-step HMAC algorithm with an interactive visualizer showing key processing and hashing.
Multiple Algorithms
Support for various hash functions including SHA-256, SHA-512, SHA-384, SHA-224, SHA-1, and MD5.
Developer Friendly
Built with clear, modular code, making it easy to integrate and extend for developers and security applications.
About HMAC
HMAC (Hash-based Message Authentication Code) is a specific type of message authentication code involving a cryptographic hash function in combination with a secret cryptographic key. It was defined in RFC 2104 and provides both data integrity and authentication.
HMAC can be used with any cryptographic hash function (MD5, SHA-1, SHA-256, etc.) in combination with a secret shared key. The cryptographic strength of HMAC depends upon the cryptographic strength of the underlying hash function, the size of its hash output, and the size and quality of the key.
The HMAC construction is resistant to extension attacks and provides strong security guarantees. It's widely used in internet protocols including TLS, IPsec, SSH, and many others for ensuring message authenticity and integrity.
How to Use
- Enter Message: Type or paste the message you want to authenticate into the message field.
- Enter Secret Key: Provide the secret key shared between sender and receiver.
- Select Hash Algorithm: Choose the underlying hash function (SHA-256 recommended for security).
- Select Output Format: Choose the desired format for the HMAC (Hexadecimal lowercase, uppercase, or Base64).
- Select Operation: Choose to 'Generate HMAC' or 'Verify HMAC'. For verification, enter the expected HMAC value.
- Process: Click the "Generate HMAC" or "Verify HMAC" button to perform the selected operation.
- View Result: The result will appear in the result box below. You can copy it to your clipboard.
Note: The visualization section shows the internal steps of the HMAC algorithm as you generate an authentication code.