Basic properties

 
Key type
Most important features / context / techniques
Quantum one-time pad (QOTP) [MTdW00] symmetric
information-theoretic, simple
Secure Assisted Quantum Computation [Chi05]
symmetric
information-theoretic, simple, delegated computation
Clifford scheme (CL) [BJ15]
public
homomorphic for Cliffords, based on QOTP
EPR [BJ15] public
homomorphic, based on CL
AUX [BJ15] symmetric
homomorphic, based on CL
TP [DSS16]
public
homomorphic, based on CL
Trap code [BGS12] symmetric
authentication, Pauli twirl
Clifford code [ABE10]
symmetric
authentication
(Signed) polynomial code [BOCG+06] ...
...
Blind Quantum Computation [AS03]
...
...
Universal Blind Quantum Computation [BFK08]
symmetric
measurement-based framework, introduction of brickwork states
Unconditionally Verifiable Blind Quantum Computation [FK12]
...
...
Extending the Delegated Verifiable Blind Quantum Computation Functionality [KW16]
...
...
Publicly Verifiable Blind Quantum Computation [Hon16]
...
...
Actively Secure Two-Party Evaluation of any Quantum Operation [DNS12]
...
...
Blind Multiparty Quantum Computing [KP16]
...
...
Interactive Proofs for Quantum Computations [ABE10]
...
...
A Classical Leash for a Quantum System [RUV12]
...
QPIP, two non-communicating servers, classical client
How to Verify a Quantum Computation [Bro15] symmetric QPIP, information-theoretic (perfect)

 

Efficiency

Offline / preparation phase

  Time (for \(n\) qubits)
Quantum power
Key size (for \(n\) qubits, security parameter \(\kappa\))
Quantum one-time pad (QOTP) [MTdW00] sample \(2n\) classical bits
none
\(2n\) classical bits
Secure Assisted Quantum Computation [Chi05]
sample \(2n\) classical bits
none
\(2n\) classical bits
Clifford scheme (CL) [BJ15] polynomial in \(\kappa\) (classical FHE)
none
polynomial in \(\kappa\) (classical FHE key)

EPR [BJ15]

polynomial in \(\kappa\) (classical FHE) none
polynomial in \(\kappa\) (classical FHE key)
AUX [BJ15] polynomial in \(\kappa\) (classical FHE), plus ~\(O(n^{2^L})\) time to generate the gadgets (where \(L\) is the number of layers of T gates)
generate single-qubit states of the form \(Z^bP^a|+\rangle\).
polynomial in \(\kappa\) (classical FHE key), plus ~\(O(n^{2^L})\) gadgets (where \(L\) is the number of layers of T gates)
TP [DSS16] polynomial in \(\kappa\) and the number of \(T\) gates to be evaluated (classical FHE, and gadget generation)

If unaided by server: generate random Bell pairs, and SWAP

If aided by (untrusted) server: Pauli and SWAP gates.

polynomial in \(\kappa\) (classical FHE key) and number of \(T\) gates (gadgets, which are themselves polynomial in \(\kappa\) in size)
Trap code [BGS12]
linear in \(nm\) (for [[m,1,d]] QECC)
none
\(O(m \log m)\) for the permutation, plus \(6nm\) classical bits
Clifford code
linear in \(n\) and \(m\) (for \(m\) check bits)
none

\(n + m\)-qubit Clifford (classical description), where\(d\) is related to security parameter

...
...
...
...
Blind Quantum Computation [AS03] ...
...
...
Universal Blind Quantum Computation [BFK08] linear in \(n\) and number of gates to be performed generate states of the form \(Z^aP^bT^c|+\rangle\)
linear in \(n\) and number of gates to be performed (size of brickwork state), classical bytes
Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
...
How to Verify a Quantum Computation [Bro15] linear in number of gates to be executed, and sample \(2n\) classical bits
generation of random single-qubit states of the form \(X^aZ^bP^cT^dH^e|0\rangle\)
\(2n\) classical bits (as in QOTP)

 

 

Encryption

  Time (for \(n\) qubits)
Quantum power
Size of cyphertext (for \(n\) qubits, security parameter \(\kappa\))
Quantum one-time pad (QOTP) [MTdW00] linear in \(n\)
Pauli gates
\(n\) qubits
Secure Assisted Quantum Computation [Chi05]
linear in \(n\)
Pauli gates
\(n\) qubits
Clifford scheme (CL) [BJ15] linear in \(n\)
Pauli gates
\(n\) qubits + poly\((\kappa) \cdot n\) classical bits

EPR [BJ15]

linear in \(n\)
Pauli gates
\(n\) qubits + poly\((\kappa) \cdot n\) classical bits
AUX [BJ15] linear in \(n\)
Pauli gates
\(n\) qubits (the classical encryptions are part of the evaluation key)
TP [DSS16] linear in \(n\)
Pauli gates \(n\) qubits + poly\((\kappa) \cdot n\) classical bits
Trap code [BGS12] polynomial in \(n\) (or linear?)
Pauli gates, SWAP gates, plus whatever is needed for applying an [[m,1,d]] error-correcting quantum code (Clifford gates?)
\(3nm\)
Clifford code [ABE10]

polynomial in \(n+m\)

(\(m\) is number of check qubits)

multi-qubit Clifford gates
\(n+m\)
...
...
...
...
Blind Quantum Computation [AS03] ...
...
...
Universal Blind Quantum Computation [BFK08]

polynomial in \(n\)

classical input: none

quantum input: gates of the form \(Z^aP^bT^c\), and Paulis

\(n\) qubits
Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
...
How to Verify a Quantum Computation [Bro15] linear in \(n\)
Pauli gates
\(n\) qubits

 

 

Evaluation

  Types of gates that can be evaluated
Time (for \(g\) gates, \(t\) T gates) Quantum power from server
Quantum power from client
Quantum one-time pad (QOTP) [MTdW00]

N/A

(technically, Paulis)

N/A

(linear in \(g\))

N/A

(Pauli gates)

N/A

(none)

Secure Assisted Quantum Computation [Chi05]
all
linear in \(g\)
universal
Paulis (decrypt/encrypt in between), SWAP, generate \(|0\rangle\) state for every T gate
Clifford scheme (CL) [BJ15] Cliffords

linear in \(g\), polynomial in \(\kappa\)

(apply gates directly, and updates keys using classical-FHE evaluation)

Clifford gates
none (homomorphic)

EPR [BJ15]

Cliffords + constant number of T-gates

linear in \(g\), polynomial in \(\kappa\)

(for T gates: apply gate directly, generate an EPR pair and teleport into it)

universal
none (homomorphic)
AUX [BJ15] Cliffords + constant number of T-gates
linear in \(g\), exponential in \(L\) (T gate depth)
universal
none (homomorphic)
TP [DSS16] Cliffords + poly\((\kappa)\) T-gates

linear in \(g\), plus \(t \cdot\) poly\((\kappa)\)

(for T gates: apply gate directly, measure the gadget)

universal none (homomorphic)
Trap code [BGS12] all

linear in \(g\)

universal
Generate encodings of \(P|+\rangle, |+\rangle\) and \((H \otimes I)|\Phi^+\rangle\). This can be done in advance; then only classical power is required.
Clifford code [ABE10] N/A
N/A N/A N/A
...
...
...
...
...
Blind Quantum Computation [AS03] ...
...
...
...
Universal Blind Quantum Computation [BFK08] all
linear in \(g\)
measurements in various angles along the XY plane
none (only classical)
Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
...
...
How to Verify a Quantum Computation [Bro15] all
linear in \(g\) (note: \(P\) is treated as \(T^2\), and \(H\) as \(HPHPHPH\))
Clifford gates, computational measurements
none (unless preparation for gates is performed online)

 

Decryption

 

  Time (for \(n\) qubits)
Quantum power
Quantum one-time pad (QOTP) [MTdW00] linear in \(n\)
Pauli gates
Secure Assisted Quantum Computation [Chi05]
linear in \(n\)
Pauli gates
Clifford scheme (CL) [BJ15] linear in \(n\), polynomial in \(\kappa\)
Pauli gates

EPR [BJ15]

linear in \(n\), polynomial in \(\kappa\), quadratic in number of T gates
Pauli gates, H, HP, computational measurement
AUX [BJ15] linear in \(n\), polynomial in \(\kappa\)
Pauli gates
TP [DSS16] linear in \(n\), polynomial in \(\kappa\) Pauli gates
Trap code [BGS12] \(n\) times poly\(m\)
Pauli gates, SWAP, plus decoding the QECC
Clifford code [ABE10] polynomial in \(nm\)
Clifford gates
...
...
...
Blind Quantum Computation [AS03] ...
...
Universal Blind Quantum Computation [BFK08] linear in \(n\)

classical output: none

quantum output: gates of the form \(Z^aP^bT^c\), and Paulis

Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
How to Verify a Quantum Computation [Bro15] constant (only one output bit)
none (output is classical)

 

 

 

Security

  Type of security
Privacy (data)
Authentication (data)
Non-malleability (data)
Blindness (computation)
Verifiability (computation)
Circuit privacy (computation)
Quantum one-time pad (QOTP) [MTdW00] Information theoretic
yes (perfect)
no
no
N/A
N/A
N/A
Secure Assisted Quantum Computation [Chi05]
Information theoretic
yes (perfect)
no
no
no
no
no
Clifford scheme (CL) [BJ15] Computational, for example LWE (based on classical FHE) yes
no
no
? (is universal circuit for only Cliffords just for Cliffords?)
no
yes (see TP)
EPR [BJ15] Computational (see CL)
yes
no
no
yes, using universal circuit
no
...
AUX [BJ15] Computational (see CL)
yes
no
no
yes, using universal circuit
no
probably in the same way as CL?
TP [DSS16] Computational (see CL)
yes
no
no
yes, using universal circuit
no
yes, if classical FHE scheme has it (with upper bound to number of T gates known)
Trap code [BGS12] Information theoretic
yes (perfect)
yes
?
no
yes
no
Clifford code [ABE10] Information theoretic
...
yes (?)
yes
N/A
N/A
N/A
...
...
...
...
...
...
...
...
Blind Quantum Computation [AS03] ...
...
...
...
...
...
...
Universal Blind Quantum Computation [BFK08] information theoretic
yes (perfect)

yes, at expense of doubling input size.

[FK12]: proof does not hold for general adversary

...
yes
no
no
Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
...
...
...
...
...
How to Verify a Quantum Computation [Bro15] Information theoretic
N/A
N/A
N/A
no
yes
N/A

 

 

 

Interaction

 

  Interaction before the computation
Interaction during the computation and/or verification
Interaction after the computation 
Quantum one-time pad (QOTP) [MTdW00] N/A

N/A

(technically, could be homomorphic for Paulis)

N/A
Secure Assisted Quantum Computation [Chi05]
none
quantum (both directions), after every gate
none
Clifford scheme (CL) [BJ15] quantum (client to server)
none (homomorphic)
quantum (server to client)
EPR [BJ15] quantum (client to server)
none (homomorphic)
quantum (server to client)
AUX [BJ15] quantum (client to server)
none (homomorphic)
quantum (server to client)
TP [DSS16]

quantum (client to server)

if limiting client quantum power: extra round (quantum, server to client) to help build gadgets

none (homomorphic)
quantum (server to client)
Trap code [BGS12] quantum (client to server)

classical for every Pauli, CNOT

quantum (client to server) for every P, H, T

(can be adapted to only classical communication, and only for T gates)

quantum (server to client)
Clifford code [ABE10] N/A
N/A
N/A
...
...
...
...
Blind Quantum Computation [AS03] ...
...
...
Universal Blind Quantum Computation [BFK08] quantum (client sends partial brickwork state to server)
classical (both directions), after every `layer' of measurements
quantum (server to client)
Unconditionally Verifiable Blind Quantum Computation [FK12] ...
...
...
How to Verify a Quantum Computation [Bro15]
quantum (client to server)

classical (both directions), after every gate

if client is generating gadgets on the fly: also quantum (client to server)

classical (server to client)

 

 

 

 

Error correction

encoding, detection, correction, which gates are transversal, ...

 

Multiparty settings

How does the encoding scale with multiple parties? Can verification stuff still be done?