When encrypting a file, for example, symmetric:
gpg -c filename
and then decrypting
The file gets decrypted without gpg asking for a passphrase.
As explained in:
The passphrase gets cached by gpg-agent for some time.
For better security, this caching should be disabled or set to the minimum possible.
Solution from the above link:
For newer versions (v2.1+), disable password caching for the agent by creating
~/.gnupg/gpg-agent.confand adding the following lines:
default-cache-ttl 1 max-cache-ttl 1
There was no such caching (issue already solved) in Whonix 13