K-9 doesn't "see" public keys in OpenKeychain

I am trying to get my K-9 gmail address to work with OpenKeychain. In OpenKeychain I have imported my full key and public keys from several others. I can send encrypted mails with no problems (until now), but when I receive mails, I get the message “This key is not available. To use this key, you have to import them as one of your own keys”. I have searched everywhere if someone has ever had the same problem, but I can’t find any solution. I can’t find any possibility to import keys within K-9, but all the necessary keys are in OpenKeychain.
I would appreciate if someone could point me in the right direction.
Thanks in advance

Hi,
is K9 connected to OpenKeychain and is your key selected under “Configure end-toend key”?

I see the same behaviour as plamya wrote.
The public key of the recipient is importet. I can send encrypted mails to him.
When I open the answer mail I see the message “This key is not available. To use this key, you have to import it as one of your own keys”. It asks for the key of the sender.
This is strange because the key of the sender is not used to decrypt e-mails to my adress but my secret key.
It is only used to verify a digital signature of the sender. I asked the sender not to sign the e-mail.
Result: Same strange message.
Any ideas ?

Maybe the sender has encrypted the message only for their own key. You know it’s not one of your own keys, but OpenKeychain doesn’t. It only knows it doesn’t have access to any keys that can decrypt the message.

Thank you cketty. That could be an explanation. But it is not. the case. I can decrypt the e-mails in Thunderbird. The signed and the unsigned one. The public key of the sender and my private key is in both mail clients the same. I suspect that this is a bug in OpenKeyChain. Perhaps also a problem between OpenKeyChain and Android 12.
Any ideas. ?

Are you sure you imported you actual GPG private key? The E2E keys created by Thunderbird are not recognised as valid private keys as they use a non-standard format.

Problem solved.
Thank you very much. Good hint. But the problem was slightly different. My private keys in Thunderbird and OpenKeyChain were not the same. That explains it. By the way, not created with Thunderbird or Enigmal but with GPG.
I was confused by the error message in OpenKeyChain. It asked me to import the sender’s key as my own key. Strange.

Just discovered that K-9 v6.308 isn’t working with OpenKeyChain any more - config is still there, but K-9 says unable to contact crypto provider.
I’m a bit unusual in that I only have a signing key (i.e. there’s no encryption key) but it’s worked fine for ages.

Well, whatever the problem was it has gone away :slight_smile:

Still on 6.308? Or did you change to .309 in the meantime? There does not seem to be any OpenKeyChain related changes, though…

Good point, I’m now on 6.309

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This is still a problem. I can decrypt one of the messages I receive and if I send myself an encrypted message. For 9 of 10 people I want to decrypt, I get the error “key is not available. To use it it you must add it as one of your own!” I have confirmed public keys for the addresses that i am getting the errors on. For the addresses I can decrypt, I have their public key but they do not appear any different from the ones that will not allow decryption. I checked the key format and all of the key formats are alike.

I found the problem. I had an older Public Key that most people were using. Hence, i could only decrypt from senders who used my new key.