A cryptographic hash function and a secret cryptographic key are used in the Hash-based Message Authentication Code (HMAC), a form of message authentication code (MAC). HMAC enables the verification of a message’s authenticity and data integrity.
HTTP, SSL, SSH, and many more communication protocols frequently use HMAC as a safe method of message authentication. HMAC is also frequently used to create safe hashes for password storage, distinct tokens for session management, and other security-critical applications.
HMAC protects sensitive information and upholds confidentiality across a number of platforms and systems, including SSL/TLS, and keeps messages safe, secure, and free from outside interference.
The sender generates the HMAC value when they want to send a message using a hash function and their secret key. The message is then sent with this value attached. The recipient uses the same secret key to run the same hash function after receiving the message and the HMAC. They can verify that the message hasn’t been altered during transmission and that the sender is who they say they are if the HMAC value they calculate matches the one transmitted with the message, only the sender and the recipient are aware of the secret key.
