Project for learning and experimenting with cryptography in go
Got some hints from https://golang.org/pkg/crypto/cipher/#NewGCM and other Go documentation examples.
As per Go's implementation of AES: The key may be either 16, 24, or 32 bytes, to select AES-128, AES-192, or AES-256 respectively. When a key is not manually specified, a securely random 32 byte key is generated.