I'm using Emacs 26.1 and GnuPG 2.1.18. The help doc for variable
epa-file-cache-passphrase-for-symmetric-encryption explains that enabling this option is a security risk and to "consider using gpg-agent which
does the same job in a safer way."
However, it does not seem that passphrases cached by gpg-agent are ever used for encryption, only for decryption. (I always get a passphrase prompt when saving a
.gpg file, even if I was able to automatically open/decrypt the file using a cached passphrase.) Conversely, setting
t allows EPA to cache passphrases for both decryption and encryption.
Therefore, it seems to me that the statement that gpg-agent "does the same job in a safer way" is incorrect. Am I mistaken that gpg-agent can only be used to cache passphrases for decryption (when using symmetric encryption)? Or are the docs wrong? (Also see How to get gpg-agent to cache the passphrases I enter when reading/saving *.gpg files?)
Additionally, the user's manual asserts that you cannot use the elisp passphrase cache with GnuPG 2.1 or 2.0, but I am doing so just fine (by enabling
epa-file-cache-passphrase-for-symmetric-encryption). Does this change in Emacs >26.1, or is it another mistake in the docs?
If these are legitimate errors in the docs, then I will file a bug report for EPA.