On Tue, Jul 27, 2021 at 02:34:28PM +0200, Ingo Klöcker wrote: > On Dienstag, 27. Juli 2021 01:32:53 CEST root wrote: > > Long story short, when the public key is downloaded to my PC as a plain text > > .asc file, and later imported using the function > > gpgme_op_keylist_from_data_start() and gpgme_op_keylist_new(), the > > key->can_encrypt, key->sign_certify, and can_sign are all 0x01. > > gpgme_op_keylist_from_data_start() does _not_ import any keys. All it does is > retrieve the meta data of the keys passed to it as data. Those keys cannot be > used for any crypto operations like signing, encrypting, etc. because the > public key data has _not_ been imported. The keys have just been listed. This > is very similar to listing the keys on a keyserver without actually > retrieving > the public keys from the keyserver. > > > Alternatively, if I do gpgme_op_keylist_start() using an email address with > > GPGME_KEYLIST_MODE_EXTERN, the key->can_encrypt, key->can_certify and > > key->can_sign are all 0x00. I've tried several email addresses found on > > keys.opengpg.org, and the result is the same. > > Using gpgme_op_keylist_start() with GPGME_KEYLIST_MODE_EXTERN does a remote > lookup on the keyserver. It does _not_ import the found keys. That's why > can_encrypt, etc. are all 0x00. You need to download and import the keys if > you want to use them. > This makes sense now. I will look into the sample codes and manual to see how I can download and import the keys after listing it. Any suggestion on where to look for them ? Hopefully, it'll be straight forward. > Alternatively, you may want to use the auto-key-locate option of gpg which > automatically locates and retrieves keys when encrypting to an email address. The codes that I am developing is actually a DLL used by another C#/C++ written in .Net framwork. Thus, the binary developed has to be portable. I will look into the auto-key-locate option for sure. > > Don't reinvent the wheel using gpgme if you can simply use what gpg provides > out of the box. Of course, you can still use gpgme for doing the encryption, > but don't try to retrieve the keys yourself if gpg can do it for you. I am new to GnuPG and this is a great tool in programming. I am not sure how to use gpg commands directly in C/C++ codes though. I thought gpgme is providing the interface to use gpg ?
Thanks again, Eric > > Regards, > Ingo > _______________________________________________ > Gnupg-users mailing list > Gnupg-users@gnupg.org > http://lists.gnupg.org/mailman/listinfo/gnupg-users _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
