Strange MDC --entrypt-to self-encryption behaviour

[H29]

Hi there,

I must admit that I did not fully unterstand what's hapenning.
So when I send an e-mail to a colleague he gets the message, that no matching private key was found.
So do I if I click on that mail in my sent-folder.

We both see Enigmail Security Info with:
Error - no matching secret key found to decrypt message
Good signature from <sender>
Note: The message is encrypted for the following User ID's / Keys:
<my correct="" id=""> ( my name and email),
<sender correct ID< ( sender name and email)</my></sender>

like described here: https://sourceforge.net/p/enigmail/forum/support/thread/b092f30e/

Setting the insecure --no-mdc-warning flag leads into that he can read my messages and I can read mails to him in my sent-folder. So the reason for that Enigmail-message was found. But how to fix it?

The other way around (he sending me a mail) work fine.

I looked into my enigmail-console which command is issued on encryption.

gpg --charset utf-8 --display-charset utf-8 --no-auto-check-trustdb --batch --no-tty --status-fd 2 -a -t --encrypt --trust-model always --encrypt-to 0xDCB68FB86823E595 -r 0x00300D000HIS0KEY -u 0xDCB68FB86823E595

And used that command to encrypt a text on my commandline to verify the mentioned warning message appears on decryption:

gpg: WARNUNG: Botschaft wurde nicht integritätsgeschützt (integrity protected)

Now the part I do not fully understand:
The output of
gpg --edit-keys (KEYID) and then showpref on his key (on his machine)

[ultimate] (1). His Name his.name@example.org
Cipher: AES, AES256, CAST5, 3DES
Digest: SHA256, SHA512, SHA1, RIPEMD160
Compression: Uncompressed, ZIP, ZLIB

and for my key (on my machine):

[ ultimativ ] (1). My Name mName@example.org
Verschlü.: 3DES
Digest: SHA512, SHA384, SHA256, SHA1
Komprimierung: ZIP, nicht komprimiert
Eigenschaften: MDC, Keyserver no-modify

So from my understanding my gpg-client is not able to use MDC for my own key in Enigmail (because my colleague does not have that feature enabled so I can not come from him)?

Basic encryption for myself is working and decryption of that does not show any warning:

gpg --armor --encrypt -r mName@example.org

[Patrick Brunschwig]

I think you better ask such questions at the GnuPG users mailing list: < gnugp-users AT gnupg.org >

[H29]

Yep, thought that shortly after this post.
The issue was fixed when my collegaue enabled MDC on his key.

So my guess is that gpg does not perform MDCs to --encrypt-to if the -r (recipient) has MDC disabled.

Thanks for your time