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Measurement Device Independent Quantum Digital Signature (MDI-QDS): Difference between revisions
Measurement Device Independent Quantum Digital Signature (MDI-QDS) (edit)
Revision as of 02:35, 3 June 2019
, 3 June 2019→Outline
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Quantum Digital Signature protocols can be separated into two stages: the distribution stage, where quantum public keys are sent to all recipients, and the messaging stage, where classical messages are sent and verified. Here, we take the case of three parties, one sender (referred to as seller) and two receivers (buyer and verifier) sharing a one bit message.<br/> | Quantum Digital Signature protocols can be separated into two stages: the distribution stage, where quantum public keys are sent to all recipients, and the messaging stage, where classical messages are sent and verified. Here, we take the case of three parties, one sender (referred to as seller) and two receivers (buyer and verifier) sharing a one bit message.<br/> | ||
The following protocol consists of only quantum communication in the distribution phase and only classical communication in the messaging phase. It uses the protocol for QDS with insecure channels [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#References|(1)]] and replaces KGP (Key generation protocol) with Measurement Device Independent KGP (MDI-KGP). Distribution phase can be divided into the following steps: | The following protocol consists of only quantum communication in the distribution phase and only classical communication in the messaging phase. It uses the protocol for QDS with insecure channels [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#References|(1)]] and replaces KGP (Key generation protocol) with Measurement Device Independent KGP (MDI-KGP). Distribution phase can be divided into the following steps: | ||
*'''Key Distribution:''' Seller uses MDI-KGP twice with buyer and verifier, individually, to generate two different [[correlated]] keys, each. Both Seller and Receiver have two keys each, one for message bit 0 and one for message bit 1. Sender's signature for a particular message bit is a conjugation of corresponding key for message bit sent to the Buyer and the Verifier. | *'''Key Distribution:''' Seller uses MDI-KGP twice with buyer and verifier, individually, to generate two different [[Supplementary Information#Correlation in Qubits|correlated]] keys, each. Both Seller and Receiver have two keys each, one for message bit 0 and one for message bit 1. Sender's signature for a particular message bit is a conjugation of corresponding key for message bit sent to the Buyer and the Verifier. | ||
*'''MDI-KGP:''' MDI-KGP consists of the following steps (only quantum communication part) from MDI-QKD protocol in [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#References|(2)]]:</br> | *'''MDI-KGP:''' MDI-KGP consists of the following steps (only quantum communication part) from MDI-QKD protocol in [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#References|(2)]]:</br> | ||
The MDI-QKD protocol requires a third party, arbitrator. The following steps are performed with Seller and each recipient, pairwise. | The MDI-QKD protocol requires a third party, arbitrator. The following steps are performed with Seller and each recipient, pairwise. | ||
**'''State Preparation:'''Seller and buyer/verifier prepare states in randomly chosen basis and randomly chosen intensity. These states are sent to the arbitrator | **'''State Preparation:'''Seller and buyer/verifier prepare states in randomly chosen basis and randomly chosen intensity. These states are sent to the arbitrator | ||
**'''Measurement:'''Arbitrator, if honest, performs [[Bell State Measurement (BSM)]] on the received states. In case of successful measurement, the outcome is a [[bell state]] which is declared over public channel. | **'''Measurement:'''Arbitrator, if honest, performs [[Supplementary Information#Bell State Measurement|Bell State Measurement (BSM)]] on the received states. In case of successful measurement, the outcome is a [[bell state]] which is declared over public channel. | ||
**'''Sifting:''' In case of successful BSM, Seller and buyer/verifier exchange the information regarding the intensity and basis used to prepare states over authenticated quantum channel. Otherwise they discard their data. The data corresponding to successful measurements are grouped into two sets, depending on the basis used for preparation. The above steps are repeated until the cardinality of both sets is more than required threshold number of elements for each set. In the end, Buyer/Verifier flips his bits in his two sets according to the Bell state obtained in each case (given in [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#Pseudo Code|Pseudo code]] below). | **'''Sifting:''' In case of successful BSM, Seller and buyer/verifier exchange the information regarding the intensity and basis used to prepare states over authenticated quantum channel. Otherwise they discard their data. The data corresponding to successful measurements are grouped into two sets, depending on the basis used for preparation. The above steps are repeated until the cardinality of both sets is more than required threshold number of elements for each set. In the end, Buyer/Verifier flips his bits in his two sets according to the Bell state obtained in each case (given in [[Measurement Device Independent Quantum Digital Signature (MDI-QDS)#Pseudo Code|Pseudo code]] below). | ||
**'''Parameter Estimation:''' | **'''Parameter Estimation:''' | ||