How to create a key and export it for encryption using GnuPG? about openpgp-php

[singpolyma]

You can see where the default key flags are set here: https://github.com/singpolyma/openpgp-php/blob/master/lib/openpgp_crypt_rsa.php#L157

As of recent commits the defaults are S and C.

If you want to add E, you will need to pass sign_key_userid an OpenPGP_SignaturePacket in addition to the key and userid packets. Set up as you see for the defaults, but add whatever settings you want (for example, also or on 0x04 to say the key can be used to encrypt communications -- see more flags in RFC4880 section 5.2.3.21)