So I happened to be browsing SO, and came across this question. As it deals more with abstract security principles and trust models than with a specific programming problem, it looked to me like a potential candidate for migration to security.SE.

That is, until I noticed the banner below the question that read:

migrated from security.stackexchange.com 1 hour ago

This question came from our site for Information security professionals.

OK, so what gives? Why was this question deemed off-topic for security.SE, and why did somebody think it would be more on-topic at SO?

Admittedly, I haven't been very active here on security.SE, so it's quite possible that there's some good and well agreed-upon reason why this question was closed here that I'm simply not aware of; if that's the case, I'd be happy with a simple pointer to the relevant policy / meta discussion.

(Even then, though, I'd still question the appropriateness of SO as a migration target.)

  • I changed the title of my question to reflect the real problem. Any suggestions to make it a better fit are welcome. May 26, 2014 at 13:40

3 Answers 3


Based on the discussion here, I've restored this question. Due to the activity following the migration, the most expedient way of handling this was to re-migrate the question and delete the other copies; rejecting the migration would've necessitated re-posting answers and potentially left broken links.

Final question: Proof that client app is using the recipient's public encryption key

Be careful with migrations; unlike normal closing, with migration you give up your say in the future of a question.


Speaking as a Sec.SE user: this question is about PKI and about the security architecture of an application. It's squarely on-topic.

Speaking as an SO user: this question is about application design with a security perspective. I personally find it to be on-topic but borderline; if I found it on SO, I'd suggest a migration to Sec.SE. Since Prog.SE was launched, part of the SO community considers that these questions belong exclusively on Prog.SE and not on SO.

Conclusion: I've voted to close on SO.

At this point in time, only your answer was newly posted on SO; if the migration is rejected, please post it again when we reopen the question on Sec.Se.


I voted to move this to SO because its a programming question. The OP is not asking how encryption works, he is asking how to implement it in an application. This issue was previously addressed on SO, there was a comment on my question before it was migrated, but it looks to somehow have gotten lost.

The question may need to be broken down into multiple questions. There is something about cloud storage at the end ("Also encrypted cloud storage like Wuala or Mega is only a marketing gag."), but that seems to be a separate question (which would likely get closed because its too broad).

Others, including mods agreed with the move. Maybe one part of this which would be a good fit would be "how can users share and verify keys/certificates for usage in end to end communication".

The issues are not really theoretical, but how will you implement them in an application.

  • 2
    I removed the sentence about cloud storage, because it seems to be more distracting than value adding. Besides that, I didn't asked about signing a message, that was part of your answer and someone commented that your answer is related to a SO post, not the question itself. I strongly disagree that it's a programming question, because I cannot tell what should be implemented. Therefore if the question remains on SO, it surely will be closed as off-topic. But I can't tell where to put it, if it's not "information security". May 22, 2014 at 13:20

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