ribordy presentation clusit · quantum cryptography – grégoire ribordy 4 technological...

Practical implementations and applications

Grégoire Ribordy, CEO

Quantum Cryptography

Quantum Cryptography – Grégoire Ribordy 2

OutlineQuantum information processingQuantum cryptography and information securityRealizing a QC channelCharacterizing a QC systemImplementationsQC-enabled hardware secure moduleCase study: Swissquantum


How to realize a « bit »

Oui

Non


Technological miniaturizationTechnological trend

The potential of quantum physics has not been fully used yet in industrial applications.

Another look at Moore’s Law

1

10

100

1000

10000

100000

1970 1980 1990 2000 2010 2020

Année

Tra

nsi

stor

s pa

r p

uce

[x

1000

]

0

10

20

30

40

50

Tai

lle

de

la g

rill

e d

'un

tr

ansi

sto

r [a

tom

es]

Limite quantique


Classical and quantum physicsClassical physics

… - 1900Describes the macroscopic world

Deterministic

Intuitive

Quantum physics1900 - …Description of the microscopic world

ProbabilisticCentral role of the observerNot very intuitive


Optical communications

Optical fibers

Optical networksDeployed in 2002: 82'000'000 km (World)

0 1 0 0 1 0 1 0 0 1

Electro – opticalconverter

Opto – electronicconverter

Optical fiber

"0""1""1"


PhotonsLight "Particules"

Quantum descriptionFragile object

Fragile !


VisionLong-term secrecy based on the laws of quantum physics

« Quantum cryptography will change the world »


Quantum cryptography

Quantum key distribution

Transmission of a random sequenceQuantum channel

Secrecy verificationClassical channel

Data encryption and transmissionClassical channel


Information securityAvailability of information and processing resources

Information leakage prevention and avoidance

Attack and intrusion detection

Reaction to threats or attacks


Quantum channelNecessary components

ChannelSingle-Photon Source

Single-Photon Detector


Photon SourcePractical single-photon sources do not existAttenuated laser pulses

Poissonian Distribution

0%

20%

40%

60%

80%

100%

0 1 2 3 4 5

Number of photons per pulse

Pro

babi

lity Mean = 1

Mean = 0.1

Absorbing Medium


Channel: Optical fiberAttenuation( ≈ transparency)

Components availability

λ [µm] α [dB/km] T10km

0.8 2 1%

1.3 0.35 44%

1.55 0.2 63%


Si

Single-photon detection (1)


Single-photon detection (2)


Characterizing a QKD System (1)

Raw key distribution rate

with q: systematic factor (< 1/2)

µ: unempty pulse probability

ν: laser pulse rate [Hz]

ηd: quantum detection efficiency

and ηt: transmission efficiency

[ ]HzqR dtraw ηµνη=

with Lf: losses in the fiber in [dB/km]

d: transmission distance

LB: Bob’s internal losses in [dB]

( )10

LdL-

tBf

10+

=η


Characterizing a QKD System (2)Quantum Bit Error Rate

with pphot: probability to detect a photon

pnoise:probability to register a noise count

πopt: probability for a photon to reach the wrong detector

dt

noisedet

pQBER

ηµη=where

optdet

optphot

noise

noisephot

noisephotopt

QBERQBER

p

p

p2p

pp

countscorrectfalsecountsfalse

QBER

+≡

π+≈+

+π≈

+=


Impact of QBER

0.40.0

Sha

nnon

Info

rmat

ion

0.1 0.2 0.30.0

0.2

0.4

0.6

0.8

1.0

QBER

)(1 QBERHI AB −=

IAESecret key rate


Distance limitation

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 20 40 60 80

Distance [km]

Pro

bab

iliti

es (

sig

nal

, err

ors

)

0%

10%

20%

30%

40%

50%

QB

ER


Distance

BB84

tc

Distance limitation (2)Useful key creation rate


Polarization CodingTypical system

LD 1

LD 2

LD 3

LD 4

QuantumChannel

Alice BobBasis 1

Basis 2

λ/2

PBS

PBS

"0"

"1""0"

Waveplates

BS

BS

BS F "1"

APD

APD

Public Channel

Unstable

Requires frequent alignment


Interferences


InterferometerClassical interference

φPort 1

Port 2

Er

1Er

2Er

0

0.5

1

0 2 4 6

Phase [radians]

Sortie 1

Sortie 2


Phase encodingQuantum optics: single-photon

φA

φ B

Alice

Bob

D2

D10

0.5

1

0 2 4 6

Phase [radians]

Output 1

Output 2

Base 1: φA = 0; π

Base 2: φA = π/2; 3 π/2

Basis choice: φB = 0; π/2

Compatible: Alice φA ⇒ Di

Bob Di ⇒ φA(φA-φB = nπ)Bas

es Incompatible: Alice and Bob ??

(φA-φB = ±π/2)


Phase encoding (2)Stability of such system ???

In practice

φA

φ B

Alice

Bob

D2

D1

10 km

10 km ± λ/10 (100 nm)

Alice

φA φB

Bob

Time (ns)

LL

0

20

40

60

80

CC

-3 -2 -1 0 1 2 3

CL + LC

+


Auto-compensated set-upTime multiplexing

Alice

BobA

B

Att.Short arm

Long arm

MF

SP


Extending the distanceFrom 100 km to 1000 km

(not necessarily short-term)

Secure relaysImproved components

Photon counting detectorsPhotonic crystal fibers: 0.2 dB/km 0.02 dB/km

Quantum repeaterFree-space links to satellites

A BB' A' B" A" B'" A'"

Telco Infrastructure


Distance limitation (3)

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 20 40 60 80

Distance [km]

Pro

bab

iliti

es (

sig

nal

, err

ors

)

0%

10%

20%

30%

40%

50%

QB

ER


Quantum cryptography enabled Hardware Secure Module

QKD Hardware QKD Hardware

Optical Fiber

Computernetwork A

Computernetwork B

Key exchange

Quantum channel

Encryption

Decryption

Classical channel

Traffic Network A to B

Traffic Network B to A

Encryptedtraffic

Encryptedtraffic

- Link encryption

- Automated key management


Block diagram

QC Hardware

Key Distillation andmanagement

Key Buffer

EncryptionNetwork interface

Supervisor

Random NumberGeneration

Classical channel

Classical channel

Classical channel

Quantum channel

Enc

rypt

ion

Laye

rK

ey m

anag

emen

tLa

yer

Qua

ntum

Cry

ptog

raph

yLa

yer


Case studySwissquantum

Secure data archiving using quantum cryptography


Problem: Secure data archivingOptimum servicecontinuity thanks to remote data replication.

High confidentiality of data transfer.


Pilot site: Swissquantum


Site pilote: Swissquantum


Technical specifications (1)Pilot site configuration

Distance: 11 kmOptical fiber type: Singlemode fiber (smf 28), dark fiberNumber of fibers: 2

Archive typeMission critical data of 30 customers (SME’s, banks, etc.), saved on 30 serversTotal data volume: 100 GbytesRemote archiving frequency: 1/day


Technical specifications (2)Quantum Cryptography Hardware

Key exchange rate: 800 bits/sKey management

Automated replacementEncryption

AES 128 (other options possible)Full authentication

Data transfer rate: 100 Mbits/s (full duplex)


Information securityAvailability of information and processing resources

Information leakage prevention and avoidance

Attack and intrusion detection

Reaction to threats or attacks


Thank you for your attention!id Quantique SAChemin de la Marbrerie 3CH-1227 Carouge

Ph: +41 22 301 83 71Fax: +41 22 301 83 79

[email protected]

ribordy presentation clusit · quantum cryptography – grégoire ribordy 4 technological...

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