Quantum CryptographyQuantum Cryptography

Presented ByPresented BySukhdeep KaurSukhdeep KaurRoll No. 5266Roll No. 5266

BCA FinalBCA Final

INTRODUCTIONINTRODUCTION

Quantum cryptographyQuantum cryptography, or , or quantum key quantum key distributiondistribution (QKD), uses (QKD), uses quantum mechanicsquantum mechanics to guarantee secure communication. It enables to guarantee secure communication. It enables two parties to produce a shared random bit two parties to produce a shared random bit string known only to them, which can be used string known only to them, which can be used as a as a keykey to encrypt and decrypt messages to encrypt and decrypt messages

FLOW OF SEMINARFLOW OF SEMINAR

HISTORYHISTORY APPROACHESAPPROACHES INFORMATION RECONCILATIONINFORMATION RECONCILATION PRIVACY AMPLIFICATIONPRIVACY AMPLIFICATION ADVANTAGESADVANTAGES ATTACKSATTACKS FUTURE SCOPE (PROSPECTS)FUTURE SCOPE (PROSPECTS) QUANTUM CRYPTOGRAPHY RESEARCH QUANTUM CRYPTOGRAPHY RESEARCH

GROUPGROUP COMPANIES WITH RESEARCH PROGRAMCOMPANIES WITH RESEARCH PROGRAM

TERMSTERMS

PHOTON PHOTON :--It is the elementry particle :--It is the elementry particle responsible for electromagnetic phenomena.It responsible for electromagnetic phenomena.It is the carrier of electromagnetic radiations. is the carrier of electromagnetic radiations.

QUANTUM ENTANGLEMENTQUANTUM ENTANGLEMENT :--It is a :--It is a physical resource like energy.It can be physical resource like energy.It can be measured,transformed and purified.measured,transformed and purified.

HISTORYHISTORY In the early 1970 In the early 1970 Stephen WiesnerStephen Wiesner, firstly introduced the , firstly introduced the

concept of quantum conjugate coding in New York. concept of quantum conjugate coding in New York. His seminal paper titled "Conjugate Coding" was rejected by His seminal paper titled "Conjugate Coding" was rejected by

IEEE Information Theory but was eventually published in IEEE Information Theory but was eventually published in 1983 in SIGACT News (15:1 pp. 78-88, 1983). 1983 in SIGACT News (15:1 pp. 78-88, 1983).

A decade later, A decade later, Charles H. BennettCharles H. Bennett, of the IBM , of the IBM Thomas J. Watson Research CenterThomas J. Watson Research Center, and , and Gilles BrassardGilles Brassard, of , of the Université de Montréal, proposed a method for secure the Université de Montréal, proposed a method for secure communication based on Wiesner’s “conjugate observables”.communication based on Wiesner’s “conjugate observables”.

In 1990, In 1990, Artur EkertArtur Ekert, then a Ph.D. student , then a Ph.D. student of Oxfordof Oxford University, developed a different approach to quantum University, developed a different approach to quantum cryptography known as quantum entanglement.cryptography known as quantum entanglement.

APPROACHESAPPROACHES

Quantum cryptographic Quantum cryptographic follows two type of follows two type of Quantum cryptographic Quantum cryptographic protocol.protocol.

Polarized photons Polarized photons Entangled photons Entangled photons

INFORMATION RECONCILATIONINFORMATION RECONCILATION

Information reconciliationInformation reconciliation is a form of error is a form of error correction carried out between Alice and Bob's correction carried out between Alice and Bob's keys,(to ensure both keys are identical).keys,(to ensure both keys are identical).

It is conducted over the public channel.It is conducted over the public channel. It is vital to minimise the information sent It is vital to minimise the information sent

about each key( as this can be read by Eve). about each key( as this can be read by Eve). A common protocol used is A common protocol used is cascade protocolcascade protocol, ,

proposed in 1994proposed in 1994

PRIVACY AMPLIFICATIONPRIVACY AMPLIFICATION

Privacy AmplificationPrivacy Amplification is a method for reducing (and is a method for reducing (and effectively eliminating) Eve's partial information effectively eliminating) Eve's partial information about Alice and Bob's key. about Alice and Bob's key.

This partial information could have been gained both This partial information could have been gained both by eavesdropping on the quantum channel during key by eavesdropping on the quantum channel during key transmission (thus introducing detectable errors), and transmission (thus introducing detectable errors), and on the public channel during information on the public channel during information reconciliation (where it is assumed Eve gains all reconciliation (where it is assumed Eve gains all possible parity information). possible parity information).

Privacy amplification uses Alice and Bob's key to Privacy amplification uses Alice and Bob's key to produce a new, shorter key, in such a way that Eve produce a new, shorter key, in such a way that Eve has only negligible information about the new key. has only negligible information about the new key.

ADVANTAGESADVANTAGES IT MAKES POSSIBLE TO PERFORM A 2-ION OPERATION ON IONS IT MAKES POSSIBLE TO PERFORM A 2-ION OPERATION ON IONS

THAT ARE NOT CLOSE TO ONE ANOTHER.THAT ARE NOT CLOSE TO ONE ANOTHER.

IT INCREASES THE COMPUTER’S ERROR THRESHOLD WHICH IT INCREASES THE COMPUTER’S ERROR THRESHOLD WHICH MEANS COMPUTERS WOULD BE EASIER TO MAKE.MEANS COMPUTERS WOULD BE EASIER TO MAKE.

STATE OF AN ION CAN BE STORED FOR A LONG TIME.STATE OF AN ION CAN BE STORED FOR A LONG TIME.

THIS PROCESS IS RELIABLE AND THE STATE THAT HAS BEEN THIS PROCESS IS RELIABLE AND THE STATE THAT HAS BEEN TELEPORTED IS AVAILABLE FOR ANOTHER ROUND OF TELEPORTED IS AVAILABLE FOR ANOTHER ROUND OF INFORMATION PROCESSING.INFORMATION PROCESSING.

ATTACKSATTACKS

In Quantum Cryptography, traditional In Quantum Cryptography, traditional man-in-the-middle attacksman-in-the-middle attacks are impossible due to the are impossible due to the Observer EffectObserver Effect..

If Alice and Bob are using an entangled photon If Alice and Bob are using an entangled photon system, then it is virtually impossible to hijack these, system, then it is virtually impossible to hijack these, because creating three entangled photons would because creating three entangled photons would decrease the strength of each photon to such a degree decrease the strength of each photon to such a degree that it would be easily detected. that it would be easily detected.

FUTURE SCOPE (PROSPECTS)FUTURE SCOPE (PROSPECTS)

The experiments suggests transmission to satellites The experiments suggests transmission to satellites is possible, due to the lower atmospheric density at is possible, due to the lower atmospheric density at higher altitudes. higher altitudes.

The current commercial systems are aimed mainly The current commercial systems are aimed mainly at governments and corporations with high security at governments and corporations with high security requirements. requirements.

Factors preventing wide adoption of quantum Factors preventing wide adoption of quantum cryptography outside high security areas include cryptography outside high security areas include the cost of equipment, and the lack of a the cost of equipment, and the lack of a demonstrated threat to existing key exchange demonstrated threat to existing key exchange protocols. protocols.

QUANTUM CRYPTOGRAPHY QUANTUM CRYPTOGRAPHY RESEARCH GROUPRESEARCH GROUP

Experimental Quantum Cryptography with Entangled Experimental Quantum Cryptography with Entangled Photons Photons

NIST Quantum Information NetworksNIST Quantum Information Networks

COMPANIES WITH RESEARCH COMPANIES WITH RESEARCH PROGRAMPROGRAM

ToshibaToshiba HPHP IBMIBM Mitsubishi Mitsubishi NEC NEC NTT NTT

Thank youThank you