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Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

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Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#121

Post by lmm »

derefr wrote: post #84
aftbit wrote: post #63

Hi, Eric here, co-creator of evil32. I posted a brief note on our site about this, but here's a little more detail. I found an old (local) backup of the private keys and used it to generate revocation certificates for each key. Fortunately, there is no way for anyone else to access or regenerate the private keys for this particular clone of the strong set, and I have been very careful with my copy - it is only availa…

> users who want to email someone discover their key by searching the keyserver for that email, then taking the newest key. This is akin to trust-on-first-use, and opts out completely from the web of trust or any kind of external verification Well, yes? What is the alternative, if I want to email someone who exists only in the form of a pseudonymous online identity?

> Well, yes? What is the alternative, if I want to email someone who exists only in the form of a pseudonymous online identity?

If you want to communicate with someone specific then presumably there's something that distinguishes that person from other people. Find a way to connect that something with a key fingerprint. E.g. if the point is that that someone is a journalist for the New York Times (as when Snowden was first looking to leak), they should publish their fingerprint in the NYT, or at least something NYT-official (like their website).

There are use cases where trust-on-first-use is adequate, sure. But there are use cases where it isn't.

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#122

Post by lmm »

mangodrunk wrote: post #59
cooper12 wrote: post #38

Earlier quoted context omitted.

Regarding the SSH randomart, it's enabled by adding `VisualHostKey=yes` to your ssh config or adding the flag `-o VisualHostKey=yes` on the command line. It was announced with OpenSSH 5.1 ( http://lists.mindrot.org/pipermail/openssh-unix-dev/2008-Jul... ) and there's also a paper on it ( http://www.dirk-loss.de/sshvis/drunken_bishop.pdf ). You can find the code/comments in `key.c` under `key_fingerprint_randomart()`.…

Sure, but what is the point of that? It's not as if I would remember all the different images. And it checks with the previous one, so what's the purpose (genuinely asking, as it looks pretty cool).

The idea is that you may not "remember" it but you'd subconsciously notice if the image was different. I'm not sure it's any better than a hex key in that regard - either way people usually just go "yes" the first time they connect - but I can imagine it might be easier for some people to notice.

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#123

Post by lmm »

masklinn wrote: post #31
sleepychu wrote: post #26

Earlier quoted context omitted.

I'm not sure if you're sincere but I don't think emoji would be easier to compare. +Might be less friendly to screen reader users?

> I'm not sure if you're sincere but I don't think emoji would be easier to compare. The point is to leverage human pattern matching so you want short-ish figures with large differences. Each hex digits is 4 bits, but each emoji is 10 bits, a 128 bits key is 13 emoji which is significantly more eyeballable than 32 hex digits, and chances are you'll notice EGGPLANT being replaced by CAMERA in 13 pictures easier than y…

> Each hex digits is 4 bits, but each emoji is 10 bits, a 128 bits key is 13 emoji which is significantly more eyeballable than 32 hex digits, and chances are you'll notice EGGPLANT being replaced by CAMERA in 13 pictures easier than you'd notice B being replaced by 8 in 32 characters.

Compare like with like - what are the two most similar emoji from that set of 2^10 ?

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#124

Post by lmm »

Fry-kun wrote: post #106

I've mentioned an idea in Phoronix forums[1] yesterday: Since most users won't bother comparing the entire signature (also applies to comparing md5/sha*/etc. hashes), it might be a good idea to map & display blocks of the sig as English words to the user. Care must be taken to avoid similar-looking and similar-sounding (homophonic) words, but since there are >150k words in Oxford English Dictionary, so it should be p…

The pgp word list was created for exactly this purpose. https://en.wikipedia.org/wiki/PGP_word_list

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#125

Post by johannes1234321 »

lmm wrote: post #120
Corrado wrote: post #118

Earlier quoted context omitted.

I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Also, I have several invites for Keybase is anyone wants one.

> I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Doesn't that undermine the whole decentralized web of trust concept? All those services are operated by US companies - or what if someone simply compromised…

> Doesn't that undermine the whole decentralized web of trust concept? All those services are operated by US companies - or what if someone simply compromised Keybase itself?

Ideally: Nothing. Keybase refers to other sources. I.e. a page on GitHub woth username and key fingerprint. So if keybase is compromises those links miss and it's no prove.

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#127

Post by delusional »

lmm wrote: post #120
Corrado wrote: post #118

Earlier quoted context omitted.

I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Also, I have several invites for Keybase is anyone wants one.

> I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Doesn't that undermine the whole decentralized web of trust concept? All those services are operated by US companies - or what if someone simply compromised…

An important part of keybase is that all proofs are publicly verifiable. When i prove i own a github account, I have to post a public gist. When you get my key from keybase, your client automatically looks at that link and verifies that the gist, and the text within (which is signed by my key) is valid.

Keybase is just the place that connects all the proofs. The actual client verifies that they are correct. As such, if keybase was every compromised they would only be able to change the link to the gist, which wouldn't do them much good without access to my github account.

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#128

Post by pflanze »

ashitlerferad wrote: post #115
voltagex_ wrote: post #104

Earlier quoted context omitted.

I'm just some guy, but I've got a stack of cards with my short ID on them - what do I do now? Toss them?

Destroy them carefully and use the opportunity to create new ones with QR codes on them with your full public key (or just the full fingerprint).

I've written software to help me create QR codes for my business card, including PGP, address, web site etc. There are many gotchas, some apps ignore some VCard fields, hence it puts copies into generic comment fields, too. Seems to work OK now. Maybe I should turn this into a web service.

https://github.com/pflanze/vcard-scm

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#129

Post by Senji »

lmm wrote: post #120
Corrado wrote: post #118

Earlier quoted context omitted.

I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Also, I have several invites for Keybase is anyone wants one.

> I think Keybase.io is a pretty good solution to the problem of key ownership. You can confirm the identity of anyone's Keybase key by comparing the fingerprint to one listed in any one of several "public" sources: Twitter, Github, Reddit, and even Hacker News. Doesn't that undermine the whole decentralized web of trust concept? All those services are operated by US companies - or what if someone simply compromised…

You can always use Namecoin.

Re: Fake Linus Torvalds' Key Found in the Wild, No More Short-IDs

#130

Post by Senji »

geofft wrote: post #110
raphlinus wrote: post #102

Earlier quoted context omitted.

Someone claims ( https://groups.google.com/forum/#!topic/sci.crypt/JSSM6Nbfwe... ) that it's just as easy to spoof 64 bit as 32 bit keys. I have no idea whether to believe him, but even if he's full of it, it's prudent to assume that if the 32 bit attack was practical 20 years ago, 64 bits is within reach today.

That's a post from 1996. I'm not sure how "easy" was calculated. Possibly both were hard but tractable, but 64 bits should have been much harder. Today it is significantly easier to collide a 32-bit key than a 64-bit one, but both are pretty easy. A 32-bit key can be collided in 4 seconds on a GPU, according to https://evil32.com . It can certainly be done on normal desktop hardware in hours. For a 64-bit key, 'JoshT…

This means state actors like three letter agencies already have this capability.
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