{"action":"created","issue":{"url":"https://api.github.com/repos/k9mail/k-9/issues/1259","repository_url":"https://api.github.com/repos/k9mail/k-9","labels_url":"https://api.github.com/repos/k9mail/k-9/issues/1259/labels{/name}","comments_url":"https://api.github.com/repos/k9mail/k-9/issues/1259/comments","events_url":"https://api.github.com/repos/k9mail/k-9/issues/1259/events","html_url":"https://github.com/k9mail/k-9/issues/1259","id":146035101,"number":1259,"title":"attached OpenPGP key thoughts","user":{"login":"Valodim","id":27813,"avatar_url":"https://avatars.githubusercontent.com/u/27813?v=3","gravatar_id":"","url":"https://api.github.com/users/Valodim","html_url":"https://github.com/Valodim","followers_url":"https://api.github.com/users/Valodim/followers","following_url":"https://api.github.com/users/Valodim/following{/other_user}","gists_url":"https://api.github.com/users/Valodim/gists{/gist_id}","starred_url":"https://api.github.com/users/Valodim/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Valodim/subscriptions","organizations_url":"https://api.github.com/users/Valodim/orgs","repos_url":"https://api.github.com/users/Valodim/repos","events_url":"https://api.github.com/users/Valodim/events{/privacy}","received_events_url":"https://api.github.com/users/Valodim/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":13,"created_at":"2016-04-05T16:06:19Z","updated_at":"2016-10-15T17:18:49Z","closed_at":null,"body":"The general idea of attaching an openpgp key to a mail is to inform a\r\ncommunication partner about one's key, for the purpose of verifying signatures\r\nand possibly to encrypt a reply. this bypasses the need for a keyserver lookup,\r\nbut also adds some 10kb to an email which is quite some overhead.\r\n\r\nThere are a couple of ways to implement the general idea of sticking one's\r\npublic key into an email, with varying levels of user involvement, adherence to\r\nstandards, among other differences.\r\n\r\nTo start off the discussion, the first distinction and decision I would like to make\r\nis whether the key should be part of the mime structure, or in the pgp data. In\r\nthe mime structure it's a regular old attachment like any other, this is already\r\nused here and there, e.g. in the Web.de App (and I think supported in current\r\nstable?). Putting the key in the pgp block will basically stick it next to the\r\nsignature data, where it will only be exposed to the pgp backend. Thoughts:\r\n\r\nin the MIME structure:\r\n+ more established (because it's not a new idea)\r\n+ if the user agent doesn't handle the key itself, the user can still import it\r\n  from the attachment (good for user-involved workflow)\r\n- users who don't have pgp get two weird attachments instead of one (bad for ux)\r\n- the attached key is part of the mime structure, so handing it to the pgp\r\n  implementation leads to more complex data flow (implementation complexity)\r\n- keys meant to establish pgp-communication can't easily be distinguished from\r\n  an attached key for somebody else (bad for implementation complexity)\r\n\r\npart of the PGP data:\r\n+ both signature and pubkey data are passed to the pgp implementation with no\r\n  further effort\r\n+ purpose of key is clear (good for implementation complexity)\r\n- no visible pubkey attachment for the user to open and import (bad for\r\n  user-involved workflow)\r\n- useless unless implementation-supported, unexpected keyblock might produce warning (I tested this: gpg gives a warning, which is shown in mutt but not in enigmail. openkeychain silently ignores the block.)\r\n- only possible for emails which are at least signed\r\n\r\nI think for establishing encrypted communication in an opportunistic way, the\r\nsecond option is the way to go. I would really love to see this working to\r\nallow keyserver-independent, tofu-style pgp encryption between K9 clients.\r\n\r\nI'll leave it at this for now, but would love to hear some thoughts. (also ping @dschuermann, @dkg. also probably gonna crosspost to openpgp-email ml)"},"comment":{"url":"https://api.github.com/repos/k9mail/k-9/issues/comments/253997729","html_url":"https://github.com/k9mail/k-9/issues/1259#issuecomment-253997729","issue_url":"https://api.github.com/repos/k9mail/k-9/issues/1259","id":253997729,"user":{"login":"sc-perth","id":10677739,"avatar_url":"https://avatars.githubusercontent.com/u/10677739?v=3","gravatar_id":"","url":"https://api.github.com/users/sc-perth","html_url":"https://github.com/sc-perth","followers_url":"https://api.github.com/users/sc-perth/followers","following_url":"https://api.github.com/users/sc-perth/following{/other_user}","gists_url":"https://api.github.com/users/sc-perth/gists{/gist_id}","starred_url":"https://api.github.com/users/sc-perth/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/sc-perth/subscriptions","organizations_url":"https://api.github.com/users/sc-perth/orgs","repos_url":"https://api.github.com/users/sc-perth/repos","events_url":"https://api.github.com/users/sc-perth/events{/privacy}","received_events_url":"https://api.github.com/users/sc-perth/received_events","type":"User","site_admin":false},"created_at":"2016-10-15T17:18:49Z","updated_at":"2016-10-15T17:18:49Z","body":"I submit the following wrench in the \"import the key that signed the mail\" plan:\r\nI have a master key, which has three sub keys, each sub key can only do one of the 3 functions (signing, encryption, authentication). If only the signing key were to be auto imported, then opportunistic encryption would not happen with me; though automatic verification would. I'm under the impression that this setup -- offline master, distinct function sub keys -- is becoming **more** normal. I do it this way because it's seamless for me with my yubikey & purportedly provides better security.\r\n\r\nI would suggest that the proposed automatic import be complicated to: identify all attached keys used to secure this e-mail, import all of them. That said, I'm not e-mail savvy enough to know if that will become an issue should there be multiple replies from multiple participants. Perhaps going the route of MIME attachments to attach the key key would cause previously attached keys to become stripped preventing this issue (replies tend to not include attachments, while forwards do).\r\n\r\nHere's wishing this feature request the best :)"}}
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