4 ms·

I mean, what you're saying here is that in addition to one-time-pad based cryptography, there is a "give a briefcase to the person"-based cryptographic system.

I mean, what you're saying here is that in addition to one-time-pad based cryptography, there is a "give a briefcase to the person"-based cryptographic system. In reality, I think lot more briefcase-based transfers are "cracked", as it were, than SSL sessions. My problem is just that the proposed mechanism relies on already having an even more perfect mechanism, and thus cannot be the "only one", but is in fact strictly weaker than this other mechanism. So we have a contradiction, and we can get rid of the notion that there exists such a thing as an "unbreakable" system (or, alternatively, that it is a useful concept)

admax88q 13y ago
No, the notion of the unbreakable one time pad is a great notion to have around. It is the good standard for crypto systems. Yes it's unworkable in practice but that's exactly why nobody really uses it. It is useful for teaching and making comparisons.
- voidlogic 13y ago
  Governments use it all the time. (Men with handcuffed briefcases and armed guards..) Before you send your submarine to sea for example, you can provide them with many gigabytes of one time pad. They can then use this for their most secret communication.
voidlogic 13y ago
No, this is a a breifcase full of one time pad. If you could fit 32 4 TB hard drives full of pad in the brief case that would allow you to send 128 TB in the future securely using something like an XOR one time pad. Assuming you are just sending ASCII and compress it before sending/XORing you could send a lot more then 128 TB of ASCII. This is pretty powerful. It means that organization which and periodically move physical assets securely can send information in a manner that is secure even if quantum computers reach their full potential.
- _kst_ 13y ago
  Was "128 GB" a typo for "128 TB"? Incidentally, the mechanism for sharing the pad doesn't have to be 100% secure, as long as you can reliably detect any compromises. If someone opens the briefcase while it's in transit, you just generate new pads and send another briefcase. To compromise the system, an adversary has to compromise the pad in transit without being detected.
0xdeadbeefbabe 13y ago
> I think lot more briefcase-based transfers are "cracked", as it were, than SSL sessions. Lots of SSL sessions are going on right now. It only takes a vulnerability like CVE-2014-0160 to change the score by 100 or so. Briefcases: 1 in the last day SSL sessions: 100 in the last day Edit: if only CVE-2014-0160 had some evocative name.

admax88q 13y ago

No, the notion of the unbreakable one time pad is a great notion to have around. It is the good standard for crypto systems. Yes it's unworkable in practice but that's exactly why nobody really uses it. It is useful for teaching and making comparisons.

voidlogic 13y ago
Governments use it all the time. (Men with handcuffed briefcases and armed guards..) Before you send your submarine to sea for example, you can provide them with many gigabytes of one time pad. They can then use this for their most secret communication.

voidlogic 13y ago

No, this is a a breifcase full of one time pad. If you could fit 32 4 TB hard drives full of pad in the brief case that would allow you to send 128 TB in the future securely using something like an XOR one time pad. Assuming you are just sending ASCII and compress it before sending/XORing you could send a lot more then 128 TB of ASCII. This is pretty powerful. It means that organization which and periodically move physical assets securely can send information in a manner that is secure even if quantum computers reach their full potential.

_kst_ 13y ago
Was "128 GB" a typo for "128 TB"? Incidentally, the mechanism for sharing the pad doesn't have to be 100% secure, as long as you can reliably detect any compromises. If someone opens the briefcase while it's in transit, you just generate new pads and send another briefcase. To compromise the system, an adversary has to compromise the pad in transit without being detected.

0xdeadbeefbabe 13y ago

> I think lot more briefcase-based transfers are "cracked", as it were, than SSL sessions. Lots of SSL sessions are going on right now. It only takes a vulnerability like CVE-2014-0160 to change the score by 100 or so. Briefcases: 1 in the last day SSL sessions: 100 in the last day Edit: if only CVE-2014-0160 had some evocative name.