Prepare-and-Send Quantum Fully Homomorphic Encryption: Difference between revisions

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===Stage 3 Client’s Correction===
===Stage 3 Client’s Correction===
'''Decryption (QFHE.Dec())
'''Decryption (QFHE.Dec())
*Input: QOTP Circuit Output State (Xa0[1]Zb0[1] ..... ⊗ Xa0[k]Zb0[k]ρ0Zb0[1]Xa0[1] ..... ⊗Xa0[k]Zb0[k]), Corresponding Encrypted Pad key (a˜0,b˜0)
*Input: QOTP Circuit Output State (<math> X^{a'^{[1]}}Z^{b'^{[1]}}\otimes.....\otimes X^{a'^{[k]}}Z^{b'^{[k]}}\rho' Z^{b'^{[1]}}X^{a'^{[1]}}\otimes.....\otimes X^{a'^{[k]}}Z^{b'^{[k]}}</math>), Corresponding Encrypted Pad key (<math>\tilde{a'},\tilde{b'}</math>)
*Output: Final outcome of the computation CρC† = ρ0 (a) Client uses skL to restore the pad key from sent encryption. (a0[i],b0[i])=(HE.Dec [i](a0[i]),HE.Dec [i](b0[i]))
*Output: Final outcome of the computation C<math>\rho</math>C<math>^\dagger=\rho'</math>
# Client uses skL to restore the pad key from sen encryption
# Client uses <math>sk_L</math> to restore the pad key from sent encryption: (<math>{a'}^{[i]},{b'}^{[i]}</math>)=(HE.Dec<math>_{sk_L^{[i]}}(a'^{[i]}</math>),HE.Dec<math>_{pk_L^{[i]}}(b'^{[i]}))</math>
# Client uses pad key and operates Xa Zb on single qubits i separately just like encryption.<br/>Let single qubit representation of the output state be Xa0[i]Zb0[i]σ0Zb0[i]Xa0[i], then operation of Pauli X,Z gates as above yields σ0
# Client uses pad key and operates <math>X^{a'^{[i]}}Z^{b'^{[i]}}</math> on single qubits i separately just like encryption.  
# Client repeats this for all single qubits and hence gets the quantum state ρ0, final outcome of the computation.
##Let single qubit representation of the output state be <math>X^{a'^{[i]}}Z^{b'^{[i]}}\sigma' Z^{b'^{[i]}}X^{a'^{[i]}}</math>, then operation of Pauli X,Z gates as above yields <math>\sigma'</math>
# Client repeats this for all single qubits and hence gets the quantum state <math>\rho'</math>, final outcome of the computation.


==Further Information==
==Further Information==


<div style='text-align: right;'>''*contributed by Shraddha Singh''</div>
<div style='text-align: right;'>''*contributed by Shraddha Singh''</div>
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