Switch AES-CBC to AES-GCM

[leonwind]

AES-GCM is the more secure cipher mode.
See

• https://crypto.stackexchange.com/questions/6029/aes-cbc-mode-or-aes-ctr-mode-recommended
• https://stackoverflow.com/questions/1220751/how-to-choose-an-aes-encryption-mode-cbc-ecb-ctr-ocb-cfb