I came from it with stuffing the vector into a QByteArrayView - and then comparing it with the same string being roundtripped thru a copy/paste operation by the user.

I explicitly keep the null byte so that you can simply pass the (pointer to the data of the) vector of bytes to the std::string c'tor. Meh! The c'tor wants const char *, but the vector is const unsigned char * so that one has to reinterpret_cast.

I don't think the trailing zero-byte should survive the conversion to c++ datastructures.

I have documented the function. The documentation is essentially a copy of the documentation of gpgme_op_random_bytes which should make clear that the function essentially behaves like gpgme_op_random_bytes (except that the gpgmepp function creates a buffer instead of taking one).

I guess it would have been better gpgmepp API to add an additional function for getting 30 zbase32 bytes and to omit the mode flag in the generateRandomBytes function instead of mirroring the API of gpgme.

I don't consider this a bug in gpgmepp's code. gpgmepp behaves exactly like gpgme (because it simply calls gpgme_op_random_bytes after creating a buffer of the requested size). With zbase32 you get 30 bytes zbase32 code and, if you requested more bytes, you get uninitialized additional bytes (which happen to be nullbytes, but that's more accidental than intentional). If anything then the problem is that gpgmepp's API is in general un(der)documented.

Yeah. It's a gpgmepp bug.

FWIW: Okay, gmime is still a wrapper around gpgme. After decryption it has the ability to get the used session key from the gpgme result structure. Thus, I have been on the wrong trail. The actual problem is not gpgme but more GnuPG's use of Libgcrypt or an actual regression in Libgcrypt. Well, Friday 13th.

This has been specified in 1997 by PGP 5 for a good reason. We talked often enough about this and it does not help to repeat your ideas over and over again. RFC9580 specifies a different protocol than OpenPGP as specified by RFC2440 and RFC4880 but alas grabbed the name OpenPGP for this.

I can't speak for gpgmpp but for gpgme. And the gpgme manual says:

b) For non-confirmed keys it returns broken OpenPGP keys (ie. without a user id and thus without important information)

Thank you very much for yours answers, explanations and effort!!!

Any hints where to find the actual crypto code which uses libgcrypt?

Maintainer of the FreeBSD notmuch port/package here. The steps below consistently trigger the problem on FreeBSD 16.0 (unreleased main branch), but there are no problems on FreeBSD 15.0. All my testing was on amd64.

Has now been backported to be released with 2.2.53

Yeah sure.

In T8101#213455, @werner wrote:

You need to use a current Windows version (and not Windows Server 2016)

keys.openpgp.org has two problems: a) it is a centralized service due to the requirement to confirm mail addresses. b) For non-confirmed keys it returns broken OpenPGP keys (ie. without a user id and thus without important information). For these reasons and the general problems with the keyserver-(networks) there is no more default.

Shall we change log_* functions also emit message to console, when file/socket is specified?

Any hints where to find the actual crypto code which uses libgcrypt?

I'm surprised that nobody did detect these problems during the long beta phase...

@thesamesam Thanks a lot.
I managed to replicate the failure somehow (for me, it fails at the importing the key).

I've attached notmuch-bug.log with debug-level guru commented out for gpg-agent:

I can reproduce it using Stuart's script from https://lists.gnupg.org/pipermail/gcrypt-devel/2026-February/006031.html.

Please tell us the information of your environment.
What the versions of gpg and gpg-agent?

Here is an attempt of mine this week:

diff --git a/g10/call-agent.c b/g10/call-agent.c
index 5e13a3e52..8949fad17 100644
--- a/g10/call-agent.c
+++ b/g10/call-agent.c
@@ -3290,13 +3290,14 @@ confirm_status_cb (void *opaque, const char *line)
    message.  If FORCE is true the agent is advised not to ask for
    confirmation. */
 gpg_error_t
-agent_delete_key (ctrl_t ctrl, const char *hexkeygrip, const char *desc,
+agent_delete_key (ctrl_t ctrl, const char *keygrip, const char *desc,
                   int force)
 {
   gpg_error_t err;
   char line[ASSUAN_LINELENGTH];
   struct default_inq_parm_s dfltparm;
   struct confirm_parm_s confirm_parm;
+  const char *keygrip2 = NULL;

We have seen the same thing on amd64 (x86_64) linux: https://bugs.gentoo.org/969501