# Time Entangled Quantum Blockchain

This answer cites a paper[$\dagger$] which purposes a quantum blockchain using entanglement in time.

"The weakness is that the research only presents a conceptual design." - QComp2018

How could a quantum blockchain which leverages time entanglement be realized?

Resources:

1. Quantum Secured Blockchain

2. Quantum Bitcoin: An Anonymous and Distributed Currency Secured by the No-Cloning Theorem of Quantum Mechanics

[$\dagger$]: Quantum Blockchain using entanglement in time Rajan & Visser (2018)

• IBM have a Q network. Maybe that can be used. I am researching this now. Sep 1, 2018 at 18:22
• @TrevorOakley Re: consensus, I was thinking that what they would have to agree on is the time. Re: classic + quantum layers: do you have any thoughts on a bloch sphere + blockchain (blochain) mashup? Also, had not made the connection that you had already commented here before til now! Nov 10, 2018 at 7:56
• There are consensus algorithms already built on time (POET). Hence time could be used in principle. I think about the bloch sphere and blockchains, there could be some utility - depends on details of the proposal. I tend to think the power of entanglement surpasses time, or bloch sphere analysis. I think something more fundamental could apply which would see the end of the consensus algorithm as we know it. The key is storing values. That is how nodes via hashing blocks created certainty. But that can be achieved via entanglement (if qubits could be stored - now possible). Nov 10, 2018 at 8:04
• My thinking regarding storing values: Quantum XOR Cipher Construction & Quantum XOR Linked List Construction. In essence: time-entangled quantum xor cipher / linked list. Nov 10, 2018 at 16:55
• phys.org/news/… Nov 10, 2018 at 17:37

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 rests on quantum particles entangled in time, rather than space. Based on the new structure, any attempt to hack or distort the blockchain would result in the link being destroyed, as entanglement is heavily critical. In their paper, Rajan and Visser explain that by encoding transactions on a quantum particle (or photon), it would be possible to entangle the past information, allowing the chronologically older blocks to vanish once they have been absorbed into the more fresh addition.

Their might be a proper chance of quantum networked time machine effect in future based on the current research arena of quantum entanglement in blockchain.