3 ms·
Are you familiar with the one time pad (OTP)? http://en.wikipedia.org/wiki/One-time_pad http://en.wikipedia.org/wiki/One-time_pad As long as the key is secure
by gcommer 13y ago
Are you familiar with the one time pad (OTP)?
http://en.wikipedia.org/wiki/One-time_pad http://en.wikipedia.org/wiki/One-time_pad
As long as the key is securely shared between the two parties, this scheme provides perfect secrecy, and the proof of this is trivial (check the link).
The main issue (and the reason OTP is very rarely used) is the key distribution. Quantum communication can solve this however by providing a channel which can be proven (to an arbitrarily high probability) to have not been eavesdropped or intercepted. Sadly, this doesn't scale at all, but it does give us a perfectly secure scheme to build up from.
http://en.wikipedia.org/wiki/Quantum_key_distribution http://en.wikipedia.org/wiki/Quantum_key_distribution
- betterunix 13y agoAnother reason one time pads are rarely used is that there it is easy to screw them up, since the key material must never be reused. In practice this is often violated.
- sirkneeland 13y ago"perfect" is a dangerous word. Whether it's someone saying a "perfect" product or "perfect" society or "perfect" anything, I tend to run in the opposite direction. What can I say, I'm a digital Burkean..
- gcommer 13y agoPhilosophically I may agree, but in this case "perfect secrecy" is a mathematically defined term with a specific definition. Basically, it is mathematically impossible for any encryption scheme to ever provide better data secrecy than the OTP, so I think calling it "perfectly secret" is perfectly alright :)
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