Date post: | 13-Apr-2017 |
Category: |
Engineering |
Upload: | shahrikh-khan |
View: | 271 times |
Download: | 0 times |
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Quantum Key Distribution In QuantumCryptography
Shahrukh Ayaz KhanSeminar Presentation
SSBT’s College of Engineering & Technology,Bambhori, Jalgaon - 425 001, Maharashtra, India
October 6, 2015
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 1/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Presentation Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 2/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 3/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
What is Cryptography?
Cryptography: the coding and decoding of secretmessages.
Cryptography is the art of rendering a messageunintelligible to any unauthorized party
dkssudgktpdy(Korean)
It is part of the broader field of cryptology, which alsoincludes cryptoanalysis, the art of code breaking
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 4/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Need For Cryptography
Suppose Alice want to send a secret message to his friendBob over an insecure channel
we have to prevent Eve from Eavesdropping oncommunication between Alice and Bob.
Figure: Meet Alice and Bob
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 5/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 6/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Cryptography
What is key?
Encryption is combine a message with some additionalinformation - known as the key and produce acryptogram.
Decryption is combine a cryptogram with some additionalinformation - known as the key and produce a message.
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 7/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Types of Cryptosystems
Symmetric - use the same (secret) key to encrypt anddecrypt a message
Asymmetric - use one key (the public key) to encrypt amessage and a different key (the private key) to decrypt it.Asymmetric cryptosystems are also called public keycryptosystems.
Figure: Process of cryprography
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 8/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
One-Time Pad
first proposed by Gilbert Vernam in 1926This cryptosystem is thus provably secure in the sense ofinformation theory (Shannon 1949)Actually, this is today the only provably securecryptosystemOnly problem is distributing the keys and it is Difficult toimplement
Figure: One time pad
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 9/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 10/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Need of Quantum Cryptography?
The problem of distributing the keys in the OTP isovercomed in Quantum Key Distribution
Using quantum effects, we can distribute keys in perfectsecrecy!
The Result is Perfect Cryptosystem, QC = QKD + OTP
Classical Cryptography relies heavily on the complexity offactoring integers.
Quantum Computers can use Shors Algorithm toefficiently break todays cryptosystems
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 11/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Quantum Elements
Quantum Mechanics depends on 2 major elements of quantummechanics: i.e heisenberg uncertainity principle and principle ofphoton polarization.
Heisenberg uncertainty principle : states that certain pairsof physical properties are related in such a way thatmeasuring one property prevents the observer fromsimultaneously knowing the value for other.Principle of photon polarization: tells that aneavesdropper cannot copy unknown Qubits due tonon-cloning algorithm.
Figure: Polarization of Light
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 12/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Overview of Quantum Cryptography
Unique property of quantum cryptography is the ability oftwo communicating users to detect the presence of thirdparty trying to gain knowledge of the key.By using quantum superposition/entanglement andtransmitting information in quantum states , acommunication system can be implemented which candetect eavesdropping.The polarization basis is the mapping we decide to use fora particular stateEntangled pairs of photon are used that affectsrandomness of measurements
Figure: Photon Polarization using BasesApril 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 13/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 14/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Quantum Key Distribution
Quantum Key Distribution exploits the effects discussed inorder to thwart eavesdropping.
It enables two parties to produce a shared random bitstring known only to them, which can be used as a key forencryption and decryption.
If an eavesdropper uses the wrong polarization basis tomeasure the channel, the result of the measurement willbe random.
There are three main security protocols for QKD: BB84,B92, and Entanglement-Based QKD.
We will only discuss BB84 here.
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 15/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
BB84
BB84 was the first security protocol implementingQuantum Key Distribution.
The key consists of bits that will be transmitted asphotons.
Each bit is encoded with a random polarization basis!
Alice and Bob talk on the telephone:
Alice chooses a subset of the bits (the test bits) andreveals which basis she used to encode them to Bob.
Bob tells Alice which basis he used to decode the samebits.
Where the same basis was used, Alice tells Bob what bitshe ought to have got.
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 16/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
BB84 with no Eavesdropping
The test bits allow Alice and Bob to test whether the channelis secure.
Figure: Comparing measurements Alices BitApril 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 17/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Cont..
Figure: Getting the Final Key
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 18/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
BB84 with Eavesdropping
If an eavesdropper Eve tries to tap the channel, this willautomatically show up in Bobs measurements.
In those cases where Alice and Bob have used the samebasis, Bob is likely to obtain an incorrect measurement
As Eve intercepts Alices photons, she has to measure themwith a random basis and send new photons to Bob.
The photon states cannot be cloned (non-cloneability).
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 19/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 20/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Merits
Nearly Impossible to stealDetect if someone is listeningSecure
Limitations
Price limits length,signal is absorbed, noise increasedAvailabilityCompete with traditional networks
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 21/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Future Scope
Future applications are in the most secure communication linesfor bank-to-ATM transactions, financial information protectionover the internet, and military and government communicationsincluding the use for ship-to-ship, ground-to-satellite, andsatellite-to-satellite communication.
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 22/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Outline
1 Introduction
2 Classical Cryptography
3 Quantum Cryptography
4 Quantum Key Distribution
5 Pros and Cons
6 Conclusion
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 23/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Conclusion
Quantum cryptography is a major achievement in securityengineering.
As it gets implemented, it will allow perfectly secure banktransactions, secret discussions for government officials,and well-guarded trade secrets for industry!
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 24/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
References
1 N. Namekata, S. Mori, and S. Inoue, Quantum keydistribution over an installed multimode optical fiber localarea network, Optical Express, 2015.
2 A. Beresford and F. Stajano, Location privacy in pervasivecomputing, IEEE Pervasive Computing, 2011.
3 K. G. Paterson, F. Piper, and R. Schack, Why quantumcryptography?, Quantum physics, quant-ph/0406147,June 2004.
4 Hidema Tanaka, Security Analysis of GeneralizedConfidential Modulation for Quantum CommunicationInternational Journal of Computer Networks &Communications (IJCNC) Vol.5, No.5, September 2013
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 25/26
Quantum KeyDistribution
Outline
Introduction
ClassicalCryptography
QuantumCryptography
Quantum KeyDistribution
Pros and Cons
Conclusion
Thank You...ShahrukhA.Khan
April 10, 2015 Shahrukh Ayaz Khan Quantum Key Distributionl 26/26