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Abel Molina, Thomas Vidick, and I proved that the correct answer is $c=3/4$ in this paper: A. Molina, T. Vidick, and J. Watrous. Optimal counterfeiting attacks and generalizations for Wiesner's quantum money. Proceedings of the 7th Conference on Theory of Quantum Computation, Communication, and Cryptography, volume 7582 of Lecture Notes in Computer ...


7

"I'm looking for an explicit upper bound on the probability of successful counterfeiting ...". In "An adaptive attack on Wiesner's quantum money", by Aharon Brodutch, Daniel Nagaj, Or Sattath, and Dominique Unruh, last revised on 10 May 2016, the authors claim a success rate of: "~100%". The paper makes these claims: Main results. We show that in a ...


6

Bitcoin uses elliptic-curve cryptography to sign transactions, which can easily be broken by Shor's algorithm. I didn't actually read the article because it looked kind of dumb, but I gathered that the author proposed using Grover's algorithm to speed up the mining process by looking for hashes more efficiently. If you had a functioning quantum computer, ...


5

Why can you not subdivide a quantum bitcoin? Anyone can create a Cryptocurrency, how it works is up to them, how well it is received is up to the public, generally it is decided by: Utility, Scarcity, Perceived Value. As of today a Bitcoin is worth USD 7,073.54, A Bitcoin is 10$^8$ Satoshis which are 0.00000001 Bitcoins, so a Satoshi is worth: 7,073.54 * 0....


3

The paper propounds that quantumizing the unabridged blockchain could address the problem of prevailing crisis to the security of blockchain encryption. While quantum cryptography has been suggested as a workaround for this problem before, the proposed design by Rajan and Visser is novel. They argue that the solution lies in developing a blockchain that ...


3

Quantum computing will not kill private communication, cryptocurrency or ecommerce but will cause fundamental changes in how these are implemented. For instance, RSA encryption standards will no longer be effective since factoring is a problem that can easily be solved with a powerful quantum computer. This will lead to the need for post-quantum cryptography ...


3

In complexity theory (quantum and classical) the distinction between construction and verification is very important, and the ability to verify certainly does not imply the ability to construct. For example, it is easy to verify that a satisfying assignment to a Boolean formula really is a satisfying assignment, but finding such an assignment given only the ...


2

I disagree. By no means is there a scarcity of quantum algorithms. Consider for example this review on Quantum Machine Learning. Therein the term qBLAS is contained for Quantum Linear Algebra Subroutines. This term describes all the quantum algorithms that exist for basic linear algebra tasks. Together with the (in)famous Grover Algorithm that gives a ...


2

How would the market determine the value of a quantum coin, potentially from different merchants or minters? tl;dr: by trading! Disclaimer: I am working on a startup that is addressing this problem I curated some thoughts on blockchain in an article entitled Tokenize Everything (& the Decentralized P2P Global Market) at the end of last year. A few ...


2

If each coin is entangled w/ the ledger, burning a coin via measuring it in the 'burn' (or 'wrong') basis would create an update in the ledger which could then be verified by anyone who had access to the ledger. See this paper: Quantum Blockchain using entanglement in time for more info on one approach. I also posted a question about time entangled ...


1

I think that if someone (Government / big company) would learn how to break currently used cryptographic algorithms, this could be unnoticed for a while but not for a long time. At that point, panic would cause a major collapse of the markets. This would have unpredictable consequences even for the Government / big company that initiated it. On the other ...


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