One-Time Pad reinvented to make electronic copying impossible
technologyreview.com
One-Time Pad reinvented to make electronic copying impossible
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Re: One-Time Pad reinvented to make electronic copying impossible
#2This 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.
Re: One-Time Pad reinvented to make electronic copying impossible
#3I 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?
Re: One-Time Pad reinvented to make electronic copying impossible
#4This 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.
This doesn't solve the key distribution problem at all:
To start off, both Alice and Bob must have their own slabs of diffusing glass and must physically meet to create a key for encoding a message later.
Like any other OTP system, key distribution — ensuring that the parties who wish to communicate securely have a shared secret (or secrets in the case of OTP; the whole point of OTP is that a key is only used once) — is the weak point. Unlike many other OTP systems, this one requires a physical meeting, which, depending on your use-case for needing crypto in the first place, may be impossible, or deadly dangerous.
At best, this complicates key compromise.
EDIT: clarifying language.
Re: One-Time Pad reinvented to make electronic copying impossible
#5>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.
Hmmm... so is paper?
Re: One-Time Pad reinvented to make electronic copying impossible
#6This 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.
It is a great way to make the key hard to copy, which is how encryption is usually circumvented in practice.
Re: One-Time Pad reinvented to make electronic copying impossible
#7Can someone explain this to me? I read the article but it didn't make sense.
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.
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.
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.
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.
Re: One-Time Pad reinvented to make electronic copying impossible
#8What'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?
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.
Re: One-Time Pad reinvented to make electronic copying impossible
#9This 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. It is a great way to make the key hard to copy, which is how encryption is usually circumvented in practice.
You misread it - they are not using any short keys.
Re: One-Time Pad reinvented to make electronic copying impossible
#10This 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. It is a great way to make the key hard to copy, which is how encryption is usually circumvented in practice.
I'm not sure you right on this. The way I'm reading it they generate the keys by sending the same random signals through each set of glass. If they send N signals through the glass and N is >= the message length then it certainly is a one-time pad. The two keys end up being as long as (or likely longer than) the message, so you can't brute force it.