From Wikipedia:
Information-theoretic security is a cryptosystem whose security derives purely from information theory. In other words, it cannot be broken even if the adversary had unlimited computing power. The adversary simply does not have enough information to break the encryption and so the cryptosystems are considered cryptanalytically-unbreakable.
List of unbreakable encryption-methods:
- Secret sharing
- Private information retrieval with multiple databases
- Reduction between cryptographic primitives or tasks
- Symmetric encryption with high entropic security
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- Why quantum cryptography isn't commercially used:
GCN Article: “There are limitations to QKD (= Quantum key distribution),” Hayford said. Photons can only be sent about 60 miles, and it is a point-to-point protocol, meaning that complete system hardware is needed at each location. Expanding a system beyond a campus or a small number of local facilities “starts to be a little impractical.” And: "There also are challenges with existing hardware, particularly in the generation and measurement of individual photons. “That is a complicated physics problem,” which NIST and other research facilities have been working on for years, he said. Ideally the photon source would generate a single photon on demand. “We can’t do that right now.”
The problem for a broad execution of QKD is, that the two parties have to know each other before communicating. And there needs to be a physical established line of communication, either from point to point or in nodes.
- Why quantum cryptography isn't commercially used:
- Pedersen commitments against the opener
- ElGamal encryption used as commitment, against the committer
My questions are:
Are there more known unbreakable encryptions? If so, please provide a link & I will extend the list.
Why aren't these schemes commercially used? Please provide an explanation (and link if possible) and I will edit the list as well.