[api]

This illustrates what's wrong with GPG: it's too hard to use. Why so many arguments for a common task? Why aren't the defaults acceptable?

[RMarcus]

The defaults are acceptable, and will produce a symmetrically encrypted file that can be quickly decrypted on even low-powered ARM cores in a reasonable amount of time.

These suggestions strike a different balance between protection and speed.

[tptacek]

You can safely just use "gpg -c" to encrypt files.