Transcript Quantum Communications Hub: Work packages

National Network of Quantum Technologies Hubs:
Quantum Communications Hub
Director: Professor Tim Spiller
Affiliation
Quantum Communications Hub: Partners
Academic partners:
York (lead), Bristol, Cambridge, Heriot-Watt, Leeds, Royal Holloway,
Sheffield, Strathclyde
Industrial partners:
R&D: Toshiba Research Europe Ltd. (TREL), BT and the National
Physical Laboratory (NPL)
Network: ADVA, NDFIS
Supplier/Consultancy (optical): Oclaro, ID Quantique
Collaboration/Consultancy (microwave): Airbus, L3-TRL
Start-ups (exploitation): Qumet (Bristol), Cryptographiq (Leeds/IP Group)
Standards/Consultancy: ETSI, GCHQ
User engagement: Bristol City Council, Knowle West Media Centre,
Cambridge Science Park, Cambridge Network Ltd
Quantum Communications Hub
Vision:
“To develop new quantum communications (QComm)
technologies that will reach new markets, enabling widespread
use and adoption in many scenarios – from government and
commercial transactions through to consumers and the home.”
Delivery:
First generation: Take proven concepts in Quantum Key
Distribution (QKD) and advance these to commercial-ready
stages. (Work packages 1-3)
Next generation: Explore new approaches, applications,
protocols and services – beyond QKD. (Work package 4)
Quantum Key Distribution (QKD)
Secure sharing of a key between two parties (Alice
and Bob!)
The quantum part is the distribution of the key, with a
promise from quantum physics that only Alice and Bob
have copies.
Once distributed, the (non-quantum) uses of the key(s)
cover a wide range of secure information tasks:
communication or data encryption, financial transactions,
entry, passwords, ID/passports…
The keys are consumables (use once only for security),
so need regular replenishment, which is “quantum”.
Quantum Communications Hub: Work packages
WP1 Short Range Consumer QKD (WP Lead: John Rarity (Bristol))
Near infra red, line-of sight
Microwave
WP2 Chip Scale QKD Components (WP Lead: Mark Thompson (Bristol))
Chip scale optics
Network switches
WP3 Quantum Networks (WP Lead: Andrew Shields (TREL))
Quantum Core Networks
Quantum Metro Networks
Quantum Access Networks
WP4 Next Generation QComm (WP Lead: Gerald Buller (Heriot-Watt))
Quantum digital signatures
Quantum Relays, Repeaters and Amplifiers
Device Independent and Measurement-device independent QKD
Quantum Communications Hub: Work packages
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WP1: Quantum secured key exchange for consumers
<€3000
<€10
Could use one-time-pad to protect the PIN
Generate one-time-pad using quantum secured key exchange
Key exchange at ATM allows user to ‘top-up’ a personal one-time-pad.
WP1: Why?
• Weekly ‘top-up’ a personal one-timepad into a personal phone/card.
• Protects against ‘skimming’
• Type your PIN into YOUR device
• Absolute security for PIN online
• Low cost: free to all customers
The competition:
• present readers provide simplistic
security based on ‘toy’ codes.
• In shops: data between card and
reader NOT encrypted during a
transaction, PIN is sent in the clear!
See http://www.cl.cam.ac.uk/~sd410/
See also google/vodafone: phone=wallet
Hacking demo
Bob meets Alice
9
WP1: The credit card Alice
New System:
Target 3x20x40mm Alice
>100MHz operation
WP1: Flexible receiver and software concept:
Standard 19” rack system with replaceable
receiver and software sub-units
WP2 Vision: Chip-based Qcomms devices
Integrated quantum photonic
Qcomms chip
1mm
Current approach
WP2: Compact chip-based QKD
• Chip-based devices for:
•
•
•
•
•
Low cost
Compact
Energy efficient
Mass-manufacture
Compatibility with current microelectronic devices
• Hub will target:
• Fully integrated and packaged QKD devices with control electronics
• Deployment in real networking situations
WP2: Targeted Applications
• Mobile devices
• Computer networks
• City wide communications
network
WP2: Chip-based QKD/WDM switches
4x4
building
block
16x16 integrated
switch
• Compact switching device for reconfigurable quantum
networks
• InGaAsP devices based on Clos switching
architecture
WP3: Quantum Networks
Today: Point-to-point fibre QKD
links
WP3: Quantum Networks
Long-Haul
Access
Metro
Explore integration of QKD in
different network segments
(long-haul, metro, access)
Key management and security
analysis of extended trusted
node network
Application development, eg
layer 3 encryption, quantum
digital signatures
Multiplex quantum signals on
conventional DWDM grid
...
...
data
Provisioning of quantum and
data channels
quantum
DWDM
DWDM
WP3: UK Quantum Network
Establish large-scale Quantum Network test-bed in UK
Implemented in stages
TREL
Metro networks in Cambridge and
Bristol
Long-haul network connecting
Cambridge-London-Bristol (NDFIS) with
possibility to extend
Cambridge
Bristol
Reading
UCL
Martlesham
(BT)
Telehouse
NPL
Access networks providing multi-user
connectivity
Southampton
A focus for application development, industrial standardisation and user engagement
Potential test-bed for the other QT Hubs and associated projects
WP 4: Emerging Quantum Communications Technologies
Quantum Digital Signatures
Quantum Repeaters
Information Theoretic Secure Digital Signatures
Amplifiers for Quantum Communications Systems
|ΨAlice>
𝑝
Bob
Noiseless amplifier
Verify
Quantum
limited
amplifier
Alice
Classical
amplifier
|ΨAlice>
Charlie
Coherent states 𝑥
Measurement Device Independent Quantum Key Distribution
Cryptographic Key Exchange in an Untrustworthy World
Alice
Bob
Untrusted
Measurement Unit
Quantum Comms Hub: Theory and Security Analysis
Contributes to all four Technology Workpackages:
Identify and remove security vulnerabilities at an early stage
Contribute to ETSI standards for QKD and other Qcomm systems
Physical level security analysis
Match physical models for analysis to practical implementations
Widely applicable channel analysis with side channel information leakage studies
Analysis of attacks and countermeasure design
Protocol level security analysis
Analysis of protocol stacks, incorporating low-level quantum and higher level conventional
protocols
Analysis of practical security advantages of new protocols such as QDS and MDIQKD
“Quantum-immune” conventional (classical) protocols
Hybrid system analysis
High speed (Gb/s upwards) systems combine QKD and conventional secure
communications protocols, trading unconditional and forward security for speed
Detailed security analysis of such hybrid systems (and mitigation against security “loss”) is
needed
Quantum Communications Hub: Work package targets
“Commercial-ready” QKD technologies...
WP1 Short Range Consumer QKD
Handheld system, leading to minimal mobile phone modification for Alice
Microwave quantum secure communications analysed and demonstrated
WP2 Chip Scale QKD Components
Chip scale Alice with semi-bulk Bob, leading to fully packaged chip scale QKD optical
modules
Network switches demonstrated on the UKQN
WP3 Quantum Networks
High bit rate link encryption
Quantum Metro Networks demonstrated in Bristol and Cambridge
Establishment and operation of the UKQN
WP4 Next Generation Quantum Communications
Quantum digital signatures deployed at Metro Network level
Quantum Relays/Repeaters for weak pulse QKD demonstrated on UKQN
Device Independent and Measurement-device independent QKD deployed at QAN level
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Partners
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The UK National Quantum Technologies Programme
aims to ensure the successful transition of quantum technologies
from laboratory to industry. The programme is delivered by
EPSRC, Innovate UK, BIS, NPL, GCHQ, DSTL and the KTN.
National Network of Quantum
Technologies Hubs:
Quantum Communications Hub
Director: Tim Spiller
Main partners: York (lead), Bristol, Cambridge,
Heriot-Watt, Leeds, Royal Holloway, Sheffield,
Strathclyde,
Toshiba Research Europe Ltd. (TREL),
BT and the National Physical Laboratory (NPL)
QCrypto – Example Key Distribution
Alice and Bob use alternative bases of individual photonic qubits
(e.g. plane polarization) to keep Eve guessing (BB84 protocol).
• Alice sends photons one by one, chosen at random
from
| > | > | > | >
• Bob chooses to measure polarization in basis
or
chosen at random.
• Bob announces publicly his list of bases used, but not
his results! (Null results are identified and discarded.)
• Alice tells Bob which data to keep, those where he used
the basis in which she transmitted.
• They agree a protocol for 0,1 in each basis to obtain a
shared bit string, the raw quantum transmission (RQT).
QCrypto – Example Key (BB84)
|
Alice
>=1
|
>=0
|
| > | > | > |
>=0
|
>=1
>| > | > | > | > …
…
Bob
Keep? yes
Bit
1
no
--
yes
yes
0
0
no
--
no
--
yes
0
no
--
…
…
QCrypto – Eavesdropping
• Eve cannot clone qubits, but she can try the same as Bob --guess a basis at random from
or
, measure the
polarization and then send on a photon to Bob polarized as
per her result.
• Out of the results which Alice and Bob keep, Eve will guess
wrong (on average) half of the time. Out of these (through
measurement in the wrong basis), Bob will (on average)
project half of these photons back to the original state
transmitted by Alice. Eve therefore corrupts 25% of the RQT
which she intercepts.
• More involved eavesdropping strategies also leave evidence:
the irreversibility of quantum measurement ensures that Eve
cannot gain information without causing disturbance.
QCrypto – Errors and key distillation
•
•
•
•
•
Using the public channel, A and B can:
- Estimate Eve’s activity
- Detect and eliminate errors in the RQT
- Distil a highly secure key
However, this costs! For every bit of information revealed
publicly, a component bit is discarded to avoid increasing
Eve’s information.
-6
•e.g. 4% RQT errors: 2000 ---> 754 bits (Eve knows ~10 bit)
-6
•
8% RQT errors: 2000 ---> 105 bits (Eve knows ~10 bit)
WP4: MDI-QKD
Current QKD systems secure
the fibre, but equipment must
be physically secure
Alice
& several “hacks” on detectors demonstrated
Bob
Eve’s
domain
Measurement Device Independent (MDI)
QKD relaxes the requirement to trust the
detectors. (The detectors can even be operated by Eve)
Measurement Unit
D1
Mitigates all attacks on the detectors.
We plan to demonstrate a practical and
efficient system for MDI-QKD.
Complimented by theoretical analysis of
MDI-QKD, as well as complete DI-QKD.
D3
PBS
BS
PBS
D2
Alice
D4
Bob
WP 4: Quantum Digital Signatures
Bob
|ΨAlice>
Alice
|ΨAlice>
• Authentication
•
Charlie
A receiver believes the message was from a known sender.
• Non-repudiation
•
A sender cannot deny sending a message, without claiming that the private key has
been compromised.
• Integrity
•
The message was not altered in transit.
• Transferable
•
The message is transferrable: Bob can be sure that if he forwards the message to
Charlie, then Charlie will also accept the message as genuinely from Alice.
WP 4: Quantum Digital Signatures
Phase encoded coherent states:
“A quantum one-way function”
Alice
Difficult
Classical
List of
Phases
Easy
Set phases
Measure phases
0
3π/
2
π/
2
Bob &
Charlie
π
The lower the intensity, the harder it is to
distinguish between the phases of the coherent states
WP 4: Quantum Repeaters
Classical amplifier: Increases the amplitude of the signal
Quantum amplifier: A perfect amplifier would violate the
No-cloning Theorem
Original
We pay the price in the form of noise:
Classical: noise is added from the technical
Imperfect
Perfect
𝑝
copy
copy
Noiseless amplifier
Quantum
limited
amplifier
limitations of the equipment
Quantum: Heisenberg’s relation prevents exact
knowledge of the signal, i.e. intrinsic noise
Solution: Non-deterministic (or probabilistic) amplifier
– Keep the success probability low
Classical
amplifier
Coherent states
𝑥
WP 4: Quantum Repeaters
Subtraction
𝑡√2𝛼⟩ ⟨𝑡√2𝛼
𝑡≈1
Vacuum
𝑟≈0
“1”
Detector

Comparison
𝑝1 √2𝛼⟩ ⟨√2𝛼 + 𝑝2 0⟩⟨0
𝛼⟩ ⟨𝛼
“0”
−𝛼⟩ ⟨−𝛼
Detector
𝛼⟩ ⟨𝛼

𝑝1 > 𝑝2
Imperfect
Indication of
Amplification
WP 4: Quantum Teleportation
RM Stevenson, J Nilsson, AJ Bennett, J Skiba-Szymanska, I Farrer, DA Ritchie, AJ Shields
arXiv preprint arXiv:1307.3197
References for WP 4
• P J Clarke, R J Collins, V Dunjko, E Andersson, J Jeffers and G S
Buller, Nature Comm. 3, 1174 (2012).
• V Dunjko, P Wallden and E Andersson, Phys. Rev. Lett. 112, 040502
(2014).
• E Eleftheriadou, S M Barnett and J Jeffers, Phys. Rev. Lett. 111, 213601
(2013).
• R J Donaldson et al., Experimental Implementation of a Quantum
Optical State Comparison Amplifier, arxiv:1404.4277.
• C L Salter et al. An entangled-light-emitting diode, Nature 465, 594–597
(2010).
• M Stevenson et al.,Nature Comm. 4, 2859 (2013).