I contacted Microsoft Security Response Center (MSRC) in regard to this matter. They confirmed the failed PGP key verification, but have not yet any explanation for that.

What are MS doing when they get it right, though? I'd look at the differences between those two to identify what they've messed up here.

Thanks. The mail is a standard, non-crypto mail with one attachment. That attachment is a TNEF file which has according to ytnef(1) just one file. That file has the name gpgolPGP.dat and contains a clearsigned message.

Sure, I zipped the eml which failed and I´ll send it by e-mail to you

Is it possible that you upload or send me a copy of such a mail (wk gnupg.org)? ZIP or tar the eml file and send it in an encrypted mail to me to make sure it won't be modified on the transport.

I checked my mails in detail, and I can confirm that the error occurs only with "Microsoft security update releases". Indeed "Microsoft security advisory notification" and "Microsoft security update summary for..." will be verified correctly.

I agree. It also happens to me. But only with mails coming from "Microsoft security update releases". Mails coming form "Microsoft security advisory notification" and Microsoft security update summary for..." are ok and are signed by the same key. It could be some trouble in MS automated email treatment.

Fair enough. Let's wait and see what others think.

Also consider that it is possible to change the key usage flags. Thus it will never be clear whether one has a fixed or unfixed public key. I'd like to close this bug because it is currently also discussed in the IETF WG.

No info received.

There is another argument for respecting the usage flags: it trims the admissible key space, if key ID in the PKESK packet is zero ('wild card') and thus all private keys have to be considered for decryption.

I disagree, and you don't have to try to convince me, the decision is with werner. I just want to give my opinion:
Bug compatibility is nothing esoteric or bad especially for a general purpose backend tool like gnupg. Being open to accepting broken input is a good thing because it will mean that we can get people out of a "broken tool vendor lock in".

i agree with @Valodim that it would be better to not have a warning at all for an attempt to decrypt from secret key whose public key has never been marked as valid for encryption. A strict failure there (as with a strict failure for lack of mdc) is a better scenario than a warning. If the user controls the secret key and they decide they want to be able to decrypt with it, they should be able to mark it as decryption-capable (if that's really what they want) and retry. But this is an action only for experts.

The same *cannot* be said for a subkey that is marked specifically for certification or signing, and not for decryption.

I understand the real world requirement for decrypting messages that have been encrypted to a revoked or expired key.

I don't see a problem. If you have the private key you can and will use it. I guess your concern is an oracle?

Dear aheinecke,

Hi Adam,

To compute the key validity (trust) more information may be needed and we can only do that after the changes have been saved. Further, no-auto-chec-trustdb will anyway delay that computation until "gpg --check-trustdb" is run (e.g. by a cron job).

success, thank you for the help!

In GnuPG 2.1, secret keys are under control of gpg-agent. Currently, it is not deleted by gpg frontend.
Please run:

$ gpg -K --with-keygrip

IIRC, rfc2440 did not forbid partial length encoding for key-material so gpg could use that. rfc4880 limits partial length encoding to non-key-material which causes this error message.

Well, I'd expect gpg not to alter my digest/compression preferences when changing my cipher preferences and vice versa. So if a user's going to have to lose his previously set preferences for a key in this manner because that's the only reasonably viable way of maintaining backwards compatibility, I think it would be appropriate to let him know beforehand and also suggest that he set it all up at once (as I've so described above) so that nothing is lost in the process.

The way the setpref command works is implementation specific and thus the OpenPGP standard is irrelevant here
.
Are you requesting a change in the behaviour of the setpref command? That would not be easy to implement for backward compatibility.

Well, iff we implement that for gpg we also need to implement it for gpgsm.

A decision must be made what the desired behaviour should be.

• marcus (Marcus Brinkmann) <noreply@dev.gnupg.org> [20170622 16:41]:

So, the default change 7y ago and the world didn't end. Closing this.

So, the default change 7y ago and the world didn't end. Closing this.

Tested this again with 2.1.18 and it works now as expected. Export secret key
just exports a key if it has no passphrase. So I think this issue can be marked
as resolved.

It is a hack in OpenKeychain to allow the use of several devices. Frankly, I am
not sure whether this is really a good idea: The security is limited by the key
for the least secure device.

So i've tested this locally with:

    export GNUPGHOME=$(mktemp -d)
    gpg --quick-gen-key 'test user <test@example.org>'
    gpg --armor --export-secret-key 'test user <test@example.org>'

(choosing no passphrase during the prompts that come up during the quick-gen-key
step). The final export step works fine.

Can you show what steps you're taking that fail for you, Andre?

I'm using latest master and I still can't export a secret key without passphrase.

And Justus also has not closed this bug or wrote that he commited something
more. So I think the 2.1.13 announcement was mistaken and this problem still
exists. (Or am I missing some option / need a different pinentry mode?)