Arbitrated Quantum Digital Signature: Difference between revisions

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* <math>G</math>: PKG's master key which is a one way function where <math>\{0,1\}^n \xrightarrow{}\{0,1\}^n</math> .
* <math>G</math>: PKG's master key which is a one way function where <math>\{0,1\}^n \xrightarrow{}\{0,1\}^n</math> .
* <math>F</math>: Public quantum one way function selected by Seller to generate quantum digest.
* <math>F</math>: Public quantum one way function selected by Seller to generate quantum digest.
* <math>m</math>: Message sent by Seller to the Verifier, where <math>m \in \{0,1\}^n</math>.
* <math>m</math>: Message sent by Seller to the Buyer, where <math>m \in \{0,1\}^n</math>.
* <math>s</math>: Random string of uniform distribution selected by the Seller, where <math>s \in \{0,1\}^n</math>.
* <math>s</math>: Random string of uniform distribution selected by the Seller, where <math>s \in \{0,1\}^n</math>.
* <math>t</math>: Random string of uniform distribution selected by the Seller, where <math>t \in \{0,1\}^n</math>.
* <math>t</math>: Random string of uniform distribution selected by the Seller, where <math>t \in \{0,1\}^n</math>.
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*<math>b_l</math>: measurement result of <math>l^{th}</math> qubit in the concerned quantum state
*<math>b_l</math>: measurement result of <math>l^{th}</math> qubit in the concerned quantum state
* <math>|F\rangle</math>: Quantum digital digest received by PKG.
* <math>|F\rangle</math>: Quantum digital digest received by PKG.
* <math>|F\rangle'</math>: Quantum digital digest generated by Verifier.
* <math>|F\rangle'</math>: Quantum digital digest generated by Buyer.
* <math>u</math>: The most number of verifiers in this scheme.
* <math>u</math>: The most number of Buyer in this scheme.
* <math>w</math>: Safety parameter threshold for acceptance.
* <math>w</math>: Safety parameter threshold for acceptance.
* <math>w_0</math>: Security threshold decided in advance.
* <math>w_0</math>: Security threshold decided in advance.
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* In this protocol, it is proven that no adversary can break the secrecy of the seller's signature private key.
* In this protocol, it is proven that no adversary can break the secrecy of the seller's signature private key.
* The quantum digital signature produced in this protocol is impossible to repudiate and cannot be forged in any condition.
* The quantum digital signature produced in this protocol is impossible to repudiate and cannot be forged in any condition.
* In the protocol the public and the private key belong to the classical bits, only the signature cipher has quantum nature.
* In the protocol the public and the private key belonging to the classical bits, only the signature cipher has quantum nature.
* No Certificate Authority is required to manage digital public-key certificate of sellers.
* No Certificate Authority is required to manage digital public-key certificate of sellers.
* If  <math>|F\rangle = |F\rangle'</math>, the measuring result <math>|0\rangle</math> occurs with probability 1, otherwise it occurs with probability <math>\frac{1+\delta^2}{2}</math>. Hence, when repeated for <math>w</math> times, the probability of equality is at least 1-<math>(\frac{1+\delta^2}{2})^w</math>.
* If  <math>|F\rangle = |F\rangle'</math>, the measuring result <math>|0\rangle</math> occurs with probability 1, otherwise it occurs with probability <math>\frac{1+\delta^2}{2}</math>. Hence, when repeated for <math>w</math> times, the probability of equality is at least 1-<math>(\frac{1+\delta^2}{2})^w</math>.
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==Further Information==
==Further Information==
Like most other classical digital signature schemes which provide unconditional security, this scheme also requires a trusted arbitrator who distributes public key to the recipients. This protocol was preceded by a few other protocols which use an arbitrator to establish quantum digital signatures, most of which used entangled states.
Like most other classical digital signature schemes which provide unconditional security, this scheme also requires a trusted arbitrator who distributes the public key to the recipients. This protocol was preceded by a few other protocols which use an arbitrator to establish quantum digital signatures, most of which used entangled states.
#[https://arxiv.org/abs/quant-ph/0109007 Zeng and Keitel (2002)]
#[https://arxiv.org/abs/quant-ph/0109007 Zeng and Keitel (2002)]
#[https://arxiv.org/abs/quant-ph/0511224 Wang et al (2005)]
#[https://arxiv.org/abs/quant-ph/0511224 Wang et al (2005)]
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