I currently need to encrypt large files (video, over 6 Gbytes) for our customers. To ensure authenticity and integrity, we chose HMAC-256 as we already use it in our internal messaging system.
But working in embedded systems, we are limitted by the memory. If the message is the whole data file, we could not stored 6Gb in memory to compute the HMAC.
Is there a dedicated protocol that breaks up the message into smaller blocks and create iterative HMAC ? Or any other way to achieve it ?