Well, in practice, public/private key encryption with large keys does achieve the same security, as does meeting in person (as required here) and simply exchanging a 100gb flash with a random OTP.<p>What this method does is makes it harder to attack if the Bob's key/OTP is physically stolen. ALthough keys embedded on secure chip-cards cheaply and commonly available now are just as secure - the authors apparently claim that the keys can be read off the glass blocks in less than 24 hours; and extracting a long key off a chip-card (even if it's just pin-protected with permanent blocking for x mistakes) would be a bigger pain, you have to physicially scan the chip with extremely expensive gear for that.<p>What this method doesn't do, is "make electronic copying impossible" or facilitate DRM, since Bob or anyone who compromises Bob's computers can freely copy and distribute the data right after the decryption.
This is not a one-time pad. It uses a key that contains less information than the message. It is still possible to brute-force the key if you have enough data.<p>It is a great way to make the key hard to copy, which is how encryption is usually circumvented in practice.
I feel like I'm missing something. Isn't this still vulnerable to "electronic" intrusion, since the light-slab-cipher has to presumably be read into some type of memory somewhere, somehow?
OT: If two people have to send a signal to each other, they should be named Alice and Bob, this goes back to Einstein's paper on the EPR paradox[1], and is based presumably on the fact that Alice starts with A and Bob starts with B.<p>Sometimes I read articles where Alice sends a signal to Charlie or something like that, and for me that is a huge red flag that indicates the author may not have payed much attention in school and/or may not have a great grasp on what they are talking about.<p>Fortunately this article is about Alice and Bob, so I am inclined to take it seriously.<p>[1] <a href="https://en.wikipedia.org/wiki/EPR_paradox" rel="nofollow">https://en.wikipedia.org/wiki/EPR_paradox</a>
Can someone explain this to me? I read the article but it didn't make sense.<p>The physical object as I understand it provides a source of random data, with the property that it is fast to do a single lookup (shine an arbitrary light pattern on it), but slow to copy the whole data.<p>This means that an attacker who steals the object, but doesn't know which lookups will be done, won't be able to copy all the data.<p>Now my objection is that the only lookups that the person who steals the object will not be able to do, is the ones based on random patterns that have not been published, i.e. the ones that are generated next time Alice and Bob meet.<p>But from that point of view, it would be no less safe if Alice and Bob simply generated a one time pad and stored it when they met.
What's involved in the handling of this glass? They claim security because heating the glass damages its structure. A fingerprint or scratch would also damage it. Is it secure because it's just so fragile that it is plain unworkable in real world conditions?<p>Also this article doesn't touch on whether the randomness generated is sufficiently random for cryptographic purposes. With enough error correction and an improper random distribution, it can become possible to break even OTP.
As far as I can tell, it's just a reasonably large on-demand (until it overheats) source of randomness. All the other OTP principles hold, the glass-generated random bits are the only new things. And you can still "electronically copy" it - viruses are great at executing code, such as dumping all the random data such a thing can generate (they even say it would only take 24 hours, and less to upload).<p>I suspect it's not even very good randomness. Long dark / bright lines from deeper scratches at either end, skewed randomness due to the atomic structure of glass (though glass is probably a reasonably good natural source, since it's not crystalline), that sort of thing happens when you're dealing with physical (hard, static) structures. And this thing has to be <i>very</i> reproducible or you can't decrypt your message, so we're not talking extracting randomness from a warm cup of tea.
There's been a lot of "physically unclonable function" work, which IMO is a lot more useful for DRM and anti-counterfeiting than for encryption.<p>The big weakness with OTPs is inadvertent key reuse, not someone stealing the key wholesale.<p>Even with quantum computing, conventional OTPs are fine, provided keys aren't reused (or lost). OTOH there are plenty of other more efficient symmetric and asymmetric systems which are still fine under quantum computing, too. (it's really not much of an issue for conventional symmetric cryptography; yes, most common public key systems in use today fall to quantum cryptography, but their are known/viable systems which would be fine)
I don't understand, where is the beef?<p>How is this qualitatively different than a plain old symmetric encryption. Bob and Alice (or whatever and for whatever reason renamed characters in their example) each have the key, Alice encrypts ( ⊕ ) sends to Bob, he decrypts.<p>Is it the idea that the key cannot be digitally copied and instead it is two pieces of glass? How is it different than Alice and Bob using a one-time key for each transmission then destroying it (using secure wipe)? What if they use hand written papers to keep their keys and burn the pages when done.<p>I am probably being dense missing some deeper idea. Anyone care to explain?
>That looks to be a significant improvement over any kind of cryptography that stores keys electronically and is therefore vulnerable to an electronic attack that can copy digital information perfectly.<p>Hmmm... so is paper?
Can someone help me understand something - Manufacturing the "glass" in order to create at least 2 identical copies will require some blueprint. I would assume that this blueprint would be stored in some database or communicated to various parties in some fashion. Couldn't hackers just get their hands on this somehow in order to reproduce the glass without having to actually physically steal the glass?
When I read articles like this, I imagine scenarios involving some United Earth Government sending vessels deep into space with one time pads which would protect us from evesdropping from advanced hostile civilizations with vast computing/cracking power. I guess it would kind of suck if your glass got broke and then you couldn't decode any more messages from Earth.
This is a very interesting way of solving the key distribution problem. It forces attackers to capture both the digital part of the key and the physical.