I just realized that my example is incorrect. It doesn't make sense to support multiple issuer subpackets on self signatures. But it is useful to do so on binary signatures and third-party certifications. Here's a better example, which gpg correctly supports. As such, this issue should be closed. Sorry for the noise.

I implemented subkey collapsing in 2.3. It is enabled by default but you can disable it it with

OpenPGP (RFC-4880) requires support for 3DES and SHA-1 thus you can't disable them. However, they are not used in practice because the key preference guarantee the use of more modern algorithms,

Since it was handled in T4908, this task is merged into that.

@mbrinkers : I think that it was fixed in GnuPG 2.2.21 by T4908: ECDH with AES-128 decryption failure when fully padded.
It was unfortunate that this bug report didn't work to solve problem, with malformed data and discussion went to unrelated thing.

I have run into an interoperability issue between BouncyCastle PGP (Java) library and gpg which seems to caused by key obfuscation.

In the SOS branch, rG1c4291c3951d: ecc-sos: Add special leading zero octet removal. should be reverted.
Instead, the S_KEY should be fixed up in read_key_file in findkey.c,
and merge_lists in protect.c.
(Then, no need to be fixed up in extract_private_key.)

Exactly same problem is there in libgcrypt.
In the definitions of curves, it uses negative constant internally in some specific places, but for other parts, we have same problems.

I should concentrate the case of ECC, in particular, ECC with modern curves.
Removing leading zero from RSA/ECC/ELGamal assuming unsigned integer would result more work.

In libgcrypt, we have another problem of GCRYSEXP_FMT_ADVANCED formatting, which is used by gpg-agent of GnuPG 2.3 with name-value list.

Confusingly, in the SSH specification, it is signed MPI.
See RFC4251, for the definition of "mpint": https://tools.ietf.org/html/rfc4251#page-8

There are more places for clean up in GnuPG.
While "MPI" in OpenPGP specification is based on unsigned integer, the default "MPI" handling of GnuPG/Libgcrypt is signed. This difference matters internally.
Formatting by "%m" with libgcrypt, it may result prefixed by 0x00 (so that it represents unsigned value, even if scanned as signed).
And because of this, existing private keys in private-keys-v1.d may have this leading zero-byte.
But the counting bits don't count this byte.

Important interoperability issue:
OpenPGP implementations should implement:

• Recovery of leading zero octets for Ed25519 key handling (secret part) and Ed25519 signature

Better to paste directly:

# SOS representation
#
# Initially, it was intended as "Simply, Octet String", but 
# it is actually "Strange" Octet String.
#

I wrote this:

Sorry, I don't know what kind of sample data that is. The reference keys have been provided by the RFC6637 author and are part of GnuPG's test suite; see (gnupg/tests/openpgp/samplekeys/ecc-sample-*).

I can't find any places where it is interpreted as signed integer.

It seems that the reference to PKCS#5 is correct. It is an issue of how to describe the case of more than 8-byte padding in OpenPGP.

Your example data is malformed, I suppose.

I also don't think that key size obfuscation is useful, after all the preferences of the key demand a certain key size.

It is easy to explain:

That means that the GnuPG Backend does not work. I do not think that the office update is the reason, me and others use GpgOL with the most recent versions of Office Pro Plus without issue.
Have you possibly modified you gnupg config files? If there is a bad value in there it would result in such an error.

Very few OpenPGP data signatures have an expiration time either, fwiw. I have never actually seen one in the wild, and no one that i know uses --ask-sig-expire or --default-sig-expire (it shows up in the cupt test suite and the apt test suite, but doesn't appear to be actually used by anything).

CMS signatures do not have a expiration time. Further the meaning of the expiration time of one of the certificates also depends on the validation model (shell or chain); thus a one-to-one relationship between these times is not possible.

For pinpadtest.py, you need to offer an option --add (adding dummy byte), when you are using Cherry ST-2xxx.

For pinpadtest.py, you need to offer an option --add (adding dummy byte), when you are using Cherry ST-2xxx.

It is not supported, by CCID protocol itself. So, it is not supported by scdaemon, and by any of card readers (which I know of), either.

It is not supported, by CCID protocol itself. So, it is not supported by scdaemon, and by any of card readers (which I know of), either.

Note that rGd3f5d8544fdb needs to be backported to 2.2 but we will wait until we have better tested it.

I am in charge of editing the current OpenPGP draft, so I will for sure keep an eye on that issue. If would appreciate if you can post your report also to openpgp at ietf org.

I am trying to reproduce your problem with my 3.3 card using my TTXS card reader.

I use the internal driver.

Are you using pcscd (is that process running) or the internal driver.? Please try the latter if you are not already using it.

It was rG07250279e7ec: * keyedit.c (keyedit_menu): Invisible alias "passwd" as "password". in 2004, which set default to rfc2440-text behavior.
And in 2007, the commit rGb550330067b6: * gpg.c (main): Disable --rfc2440-text and --force-v3-sigs by default. changed the default to no-rfc2440-text.

I see. Thanks for your explanation.

I see. Thus the problem is that IPWorksOpenPGP does not create proper OpenPGP private keys. I guess they use OpenSSL with their different CRT parameter style and do not convert them correctly. RFC-4880 says this in 5.5.3:

The secret key is this series of multiprecision integers:
o  MPI of RSA secret exponent d;
o  MPI of RSA secret prime value p;
o  MPI of RSA secret prime value q (p < q);
o  MPI of u, the multiplicative inverse of p, mod q.

At the time the verification is done some output has already been written to the file 'signed'. When checking whether the deprecated abbreviated format

The digest algorithm used is computed based on the preferences in the key if encryption is also used. Thus this should always work and any decent key has sha256 in its preferences. In case sha1 has a higher precedence, as seen on old keys, --personal-digest-preferences can be used to prefer sha256. However, it is way better to fix the key. The easisies way to do that is to change the expiration date - then the new standard preferences will be used.

Thanks so much your helps.
With new version 3.1.6, I can generate key on Kleopatra tool and use key stored in smartcard.

There was indeed a problem. With a test card I could reproduce the issue and fix it.

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