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Old 13th July 2014
cravuhaw2C cravuhaw2C is offline
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I thought I had done so an hour earlier, here.
By now you will have noticed that I'm a bit dense but I've a good excuse: I'm in my late 60s.

In your future replies to my posts, please do give me a bit of leeway.

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All that these systems do is prove is that the person with the private key has signed the plaintext, and that it subsequently arrived without change. Any other comfort or feeling of safety you take beyond that simple fact is an assumption on your part.

No digital signature system, including the GPG toolset you are familiar with, can prevent that plaintext from attacks before it is signed, nor protect you if the person who has signed it are themselves a bad actor.
You're absolutely right and I totally agree with you on the above.

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This inherent weakness in established frameworks is one of the reasons that OpenBSD developed signify(1), as it limits the chain of trust to a single authority.
What is that single authority? Thanks in advance for your answer.
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Old 13th July 2014
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What is that single authority?
For OpenBSD software, it is The OpenBSD Project (the "Project"), in two ways:
  1. By the Project member who issued signify(1) -G to create the key pair. The public key having been distributed in /etc/signify by the Project in its distributions, and the private key managed by applicable members of the Project.
  2. By the Project members who use signify(1) -S to sign messages*, which may be source code components (break/fix patches for releases, and as of today, Portable LibreSSL), kernels and installation filesets, distributable third party firmware, and all distributed pre-compiled binary packages of third party software that has been configured to run on OpenBSD.
* Message being the term used in signify(1) for the plaintext that is to be cryptographically signed or verified.
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Old 13th July 2014
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I know next to nothing about crypto, so I have a really dumb question. I just can't get past it, so I'd like to ask:

When you install the initial unverified OS, how can you trust anything it's telling you? Isn't it possible, at least in principle, that the bad guys have tampered with and corrupted it such that when you think you're running signify on it, you get bogus output that says "everything is ok" ?
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Yep. This is why you are given the SHA-2 hashes -- it is your responsibility to review them and compare them from multiple mirrors.

And while the SHA algorithms are US NIST Standards -- meaning you may not trust them due to the NIST's ties to another famous government agency that can't get out of the news no matter how much it wants to -- they were openly developed and later adopted by NIST, and the hashes can be checked by a vast number of tools across all sorts of computing platforms.
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Old 13th July 2014
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I know next to nothing about crypto, so I have a really dumb question.
Me too, me too.

If you think you're dumb, I'm even dumber.

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Originally Posted by jggimi View Post
When you install the initial unverified OS, how can you trust anything it's telling you? Isn't it possible, at least in principle, that the bad guys have tampered with and corrupted it such that when you think you're running signify on it, you get bogus output that says "everything is ok" ?
I second that.

About two to three years ago I attended a seminar hosted by developers of some anonymity software. I think it was Tor or Tails.

Anyway one of them advised those who were unable to obtain the developers' public signing keys in person to download their software from several different FTP sites hosted in different countries, compared their digital signatures and over a period of time, if nothing to the contrary shows up, we can then trust their public keys. We know now that this logic is wrong.
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-- it is your responsibility to review them and compare them from multiple mirrors.....
My dear friend, I hate to say you're wrong on this point.

What if all the mirrors have been compromised?

It happened to Gentoo once, many years ago.

It was in the news a few months ago that the NSA is planning to recruit 6,000 IT professionals to be sent to all of their offices over the world for assignment.
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Old 13th July 2014
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All the hashes prove is whether the plaintext has been altered. If the message and the hash have been compromised, you are out of luck. If you are comparing hashes from your nearby mirror with hashes from the central distribution site, you have done all you can. You must trust that the central site has not been compromised, or is not otherwise being managed by bad actors.

The addition of a signature framework from the central site merely adds one form of authentication. It does not assure you of anything else.
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Yep. This is why you are given the SHA-2 hashes -- it is your responsibility to review them and compare them from multiple mirrors.
Thanks jggimi, I should have thought of that!
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