About this Tool
HMAC (Hash-based Message Authentication Code) is a mechanism for message authentication using cryptographic hash functions combined with a secret key. Unlike simple hashing, HMAC provides both data integrity and authenticity verification. It's widely used in API authentication (like AWS Signature), JWT signing, and secure communication protocols. HMAC can use various hash functions (MD5, SHA-1, SHA-256, SHA-512) with SHA-256 being the most commonly recommended.