HMAC Generator

This tool computes an HMAC value for a given secret key and message using a selectable hash function. It is designed for developers and security engineers who need verifiable data authenticity in API calls, webhooks, and data payloads. The output MAC ensures that any alteration of the message will be detectable by the recipient who also possesses the shared secret key.\n\nThe computation follows the HMAC algorithm as defined in RFC 2104. If the key is longer than the hash function's block size, it is hashed first; then the key is XORed with ipad and opad constants, and the inner and outer hash passes are performed with the message as input. The tool presents the result in hex and base64 formats.\n\nSupported hash families include SHA-1, SHA-256, SHA-384, SHA-512, and MD5 (with caution due to known weaknesses). The user can choose the algorithm to reflect security requirements and to match server-side validation. Inputs are treated as bytes encoded in UTF-8 unless a different encoding is specified.\n\nThis tool is valuable for API integrators, backend systems, and security auditors seeking deterministic MACs for testing, auditing, and integration pipelines. By avoiding storage of keys and exposing results only to authenticated users, it supports secure development and verification workflows.