Photon phreaking:

What quantum can (actually) do for security

Gemalto Crypto Club 23 Feb 2017
Alan Robertson
Sarah Kaiser

progression from bit to qubit

Quantum Operations

  • Classical: Bitflip
  • Quantum: Rotations about some axis
  • Quantum: Measurement is the overlap between the state and some basis vector
bloch sphere

Quantum Measurement

  • Requires a basis
  • Outcomes are non-deterministic
  • Destroys phase information, only can measure once
bloch sphere

Quantum System Properties

  • No-Cloning Theorem: Quantum states cannot be copied
  • Entanglement: The state of a qubit is "correlated" with the state of another qubit
    • You cannot describe the effect of a rotation on only one qubit in set of entangled qubits

A Pathological Example

classical pathological problem

A Pathological Example

classical pathological problem

Quantum Algorithms

Deutch-Jozsa: Free$^{*}$ parallelism, reduces from $O(2^{n-1})$ to $O(1)$ function calls

Grover's Algorithm: Search an unsorted list for an$^{**}$ element in $O(\sqrt{n})$, best classical is $O(n)$

Shor's Algorithm: A faster prime factoring algorithm, because fourier transforms are unitary

Shor's Algorithm

GNFS: Generate polynomials and hope that their roots form a smooth ring such that the 'square root' of the ring is a homomorphism to the prime factors

Shor's algorithm: Find the period of the prime field using the quantum fourier transform, the 'square root' then gives the prime factors

Common Myths and Misconceptions

  • Quantum computers are NOT universally faster or more powerful than classical computers

  • Quantum computers will NOT be here tomorrow.
    have:100 qubits / need: 100 million

  • Dwave is NOT a quantum computer. Evidence shows quantum annealer at best

  • There is no one right material or system to make qubits

Why don't we all have quantum keys?

  1. Hardware developments

  2. Distance/Loss: $\approx 300$ km

  3. Realistic device security models

One approach to
overcoming loss:

QKD receiver satellite

QKD Hardware Security:

Functionality $\neq$ security

Commercial QKD devices

id Quantique Clavis 2

QKD receiver satellite

Reciever payload schematic

Single photon detector unit

detector unit
Geometry model

Integrated optical assembly (IOA)

IOA schematic
IOA photo

Acquisition pointing and tracking (APT)

detector unit
Geometry model