Performance issue when decrypting large set of data with hardware AES-NI accelerator 

1. Encrypting large data buffers, using only cipher.doFinal(buffer) call is 
slow. Hardware acceleration kicks in only after encrypting multiple buffers 
in a loop. 
2. Splitting encryption into many cipher.update calls, followed by 
cipher.doFinal, triggers the acceleration almost immediately. Should be done 
automatically inside a single cipher.doFinal(chunk) call (see 1.) 
3. Most significant problem: Splitting DEcryption into many cipher.update 
calls, followed by cipher.doFinal, does not trigger the acceleration. 
Hardware acceleration kicks in only after encrypting multiple buffers in a 
loop. Meaning that decryption of gigabytes of data cannot be accelerated by 
AES-NI hardware. 

See https://stackoverflow.com/questions/48905291/java-9-aes-gcm-performance