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https://github.com/robertdavidgraham/hunter-dkim
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@@ -59,7 +59,7 @@ Many can't be validated. They are sent from domains that don't use DKIM
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to sign outgoing emails. Others used DKIM when sent, but we can no longer
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find the public-keys that would authenticate them (it's been years).
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### "Can't signatures can be faked, replayed, forged, or cheated?"
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### "Can't signatures be faked, replayed, forged, or cheated?"
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Not cryptographic signatures, at least, not in any practical/reasonable manner.
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@@ -90,7 +90,7 @@ The signature covers both the metadata and the body. Yes, some email metadata is
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the signature, esoteric things like `X-Received:` headers. But the signature does cover the
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ones we care about: `Date:`, `From:`, `To:`, and `Subject:`.
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### "OKay, the email and metaday, but what about the envelope?"
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### "OKay, the email and metadata, but what about the envelope?"
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Several people have cited this Wikipedia article that says that
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[DKIM signatures do not encompass the message envelope](https://en.m.wikipedia.org/wiki/DomainKeys_Identified_Mail).
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@@ -98,7 +98,7 @@ This is correct, but it doesn't mean what you might think it means.
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It's like if somebody sent you a printed copy of this email. The address
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on the outside is unrelated to the contents -- it doesn't mean the contents
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aren't authenticate.
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aren't authenticated.
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In any case, Google forces the two to be the same. If the email says `From:` a
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GMail account, and it was authenticated by GMail's DKIM key, then it came from
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@@ -111,11 +111,11 @@ DKIM verifies the contents of that field (that somebody didn't alter after signi
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but not that it's the correct date. Any fraudulent information can be put here.
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But the fraud would have to occur at the time the email was sent. And that time
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would have be before October 2016, when GMail changed their DKIM signing keys.
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would have to be before October 2016, when GMail changed their DKIM signing keys.
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Thus, it's effectively timestamped "some time after January 2012 and before October 2016".
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In other words, we know it came from Vadym Pozharskyi, but he couldn't sent it
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In other words, we know it came from Vadym Pozharskyi, but he couldn't have sent it
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around a year later than the authenticated email headers claimed he sent it, like April 2016
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instead of April 2015.
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@@ -142,7 +142,7 @@ of the old key, including archives of old sites, log files from servers, and so
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on.
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Thus, in theory the system only works when the domain in question is currently
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providing the public-key to validate signatures, in practice we can know GMail's
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providing the public-key to validate signatures, but in practice we can know GMail's
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old key even if they don't provide it directly.
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The proper key is one of the files in this project, but of course, I could
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@@ -222,7 +222,7 @@ conspiracy was this sophisticated, they could do better emails. This one is lame
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### "How did you see that secret metadata, in a debugger?"
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In some cases, metadata in files like photographs require special tools. But emails
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are just text, even the metadata. You can open in any text editor. Just click
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are just text, even the metadata. You can open them in any text editor. Just click
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on this [link](https://raw.githubusercontent.com/robertdavidgraham/hunter-dkim/main/Meeting%20for%20coffee.eml)
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and see for yourself.
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