HMAC Hash Online Generator This HMAC hash generator uses a cryptographic hash function such as SHA-256, SHA-512 and a secret key known as cryptographic key. Hash-based message authentication code (HMAC) is a message authentication code. HMAC is more secure than any other authentication codes as it contains hashing as well as MAC. Use the above HMAC hash generator to generate HMAC authentication code. If this tool was helpful, tweet it or share it.