What is the current state of research on quibit commitment?

It seems that the answer is not 2001 but it seems to me that a lot of these pdf are referring to a old protocols of quantum bit commitment 1997, where the impossibility of that scheme has been proved for a unconditionally (or perfect) security of qubit commitment. Other sources, such ash 2012 propose a practical version of qubit commitment which employs another protocol, and shows that qubit commitment can be indeed practically secure.

I have found 2015 (last update of the page) these sentence that might be what I was definitely looking for:

Bit commitment can be realized classically in an computationally secure sense. More precisely, the protocols are either computationally hiding (in which case it is only computationally secure from Alice's point of view) or computationally binding (computationally secure from Bob's point of view). Moreover, it is not hard to prove that information-theoretically secure bit commitment protocols cannot exist classically. Interestingly, it could be shown that the same is true if we allow Alice and Bob to use quantum mechanics.

And what about string commitment? For what I got, It's a way of committing multiple qubits together in order to achieve a commitment that increases with the number of qubits committed in the strings. But it seems that also string commitment is impossible as well. 2005

So is the research on this topic finished? Is there anything to do on the topic of qubit commitment? Does protocol can commit only z-basis states (such as 0 or 1) or are they able to commit a full qubit (such as any superposition of states).

  • $\begingroup$ "Classical" commitment schemes of interest usually include a protocol to prove knowledge of the value committed. $\endgroup$ Dec 7, 2015 at 22:29


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