By default, messages are encrypted to all recipients (To,
CC, BCC headers). Thus, you will not be able to decrypt
your own messages. To make sure that messages are also encrypted to
your own key(s), several alternative solutions exist:
encrypt-to option in the file gpg.conf (for
OpenPGP) or gpgsm.conf (for S/MIME with EasyPG).
See Invoking GPG in Using the GNU Privacy Guard, or
See Invoking GPGSM in Using the GNU Privacy Guard.
mml-secure-openpgp-encrypt-to-self (for
OpenPGP) or mml-secure-smime-encrypt-to-self (for
S/MIME with EasyPG).