4 ms·
One-time pads are extremely impractical and error-prone. You need: 1. A secret key as long as the plaintext. 2. A consistent source of true randomness and a w
by throwawaymath 7y ago
One-time pads are extremely impractical and error-prone. You need:
1. A secret key as long as the plaintext.
2. A consistent source of true randomness and a way of sampling it such that your secret key is truly random.
3. To never reuse a key once it's been used once.
Imagine the ramifications of retrofitting servers to use one-time pads for TLS. Moreover, essentially everything we take for granted in cryptography relies on constructions which use pseudorandom permutations and generators. Even if we resolved all these problems and forged ahead in a brave new world using stream cipher-like constructions based on one-time pads, we'd still have to rethink all of public-key cryptography.
This impracticality is one of the major reasons we moved on from information theoretic security to complexity theoretic security by the mid 20th century.
- TheOperator 7y agoSure of course its incomprehensibly impractical.
- gpm 7y agoFor what it's worth, quantum computers might give a provably correct source of 2 (random numbers). The version I saw (requires 2 quantum devices): http://www.henryyuen.net/fall2018/scribe2.pdf http://www.henryyuen.net/fall2018/scribe2.pdf New paper that claims to do it with only one quantum device: https://arxiv.org/pdf/1804.00640.pdf https://arxiv.org/pdf/1804.00640.pdf