Okay, playing with it, it's not *horrible*.
% echo "hello world" | aespipe
Password:
Error: Password must be at least 20 characters.
Of course, it's is stopping me from doing providing "00000000000000000000" as the password either:
% echo "hello world" | aespipe | xxd
Password:
00000000: 403b 05ac 272e 04ad 2238 61a9 0363 fba0 @;..'..."8a..c..