Hi Kaleb,
The reason why I've considered stream encoding is that I need ability to encode big amounts of data (several gigs) of fixed size with low memory footprint (less than 50 megabytes) using AES-GCM. The idea is to divide big input into chunks of apropriate size, load and process them one by one until entire input is processed. With current implementation of AES-GCM in WolfSSL we are unable to do that as it requires entire input to be preloaded.
One of possible solutions is to calculate authentication tag on the fly during encryption. Intermediate authentication tag vaules could be saved into Aes structure. Message authentication could also be implemented using streaming approach or be combined with decryption.
Regards,
Yaroslav