Quantum Cryptography

QUANTUM CRYPTOGRAPHYASeminar Presentation On

SEMINAR COORDINATOR:Mr. Manas Singhal(Assistant Professor)SEMINAR GUIDE:Mrs.SHUCHITA SEXANA (Assistant Professor)PRESENTED BY:NAMAN KUMAR(1208231100)EC 3rd YearSection: JMIT(MORADABAD)

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CONTENT

Basic termsWhat is cryptography?The processAdvantages and Limitations of cryptographyRSA Crypto Scheme OTP (One Time Pad)Public Key CryptographyQKD (Quantum Key Distribution)What is quantum cryptography?Polarization of lightHeisenbergs Uncertainty PrincipleElement of quantum theoryQubits Quantum communicationBB84 ProtocolAdvantages and Disadvantages of Quantum cryptographyFuture aspect ConclusionRefrences

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BASIC TERMSPlain Text -Plain textis a pure sequence of character codes. Basically its is original message.Encryption Algorithm It is the process of encoding messages or information in such a way that only authorized parties can read it. Cipher Text -Cipher text is also known as encrypted or encoded information. Its is the combination of key and plain text.Decryption Algorithm It is reverse process of encryption.Eavesdropping- It is secretly listening to the private conversation of others without their consent.

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WHAT IS CRYPTOGRAPHY?Cryptography (derived from the Greek words kryptos and graphein meaning hidden writing) is the science of codes and ciphers.

Cryptography is the art of encoding and decoding messages of secure communications.

Cryptography is of increasing importance in our technological age using broadcast, network communications, Internet ,e-mail etc.34

Encrypted messages can sometimes be broken by cryptanalysis, also calledcode-breaking, although modern cryptograph techniques are virtually unbreakable.Fig.1-Block diagram of cryptography

eavesdropping

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THE PROCESSFig. 2- Process of cryptographyA-A16

ADVANTAGES OF CRYPTOGRAPHYIt hides the message and your privacy is safe.Only the person who have the key would be able to read the desired message.

LIMITATIONSKey can be hacked easily.Not efficient.

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RSA CRYPTOGRAPHYRSA stands forRon Rivest,Adi ShamirandLeonard Adleman.RSA consist a single key.

It provide more security but still it can be hacked.It take lot of time to generate and regenerate the code.

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OTP (ONE TIME PAD)One-time pad(OTP) is anencryptiontechnique that cannot be crackedif used correctly.

Fig.3- Example of one time pad 19

Here the problem raises how to get the key to the decrypting party safely or how to keep both keys secure.One-time pads have sometimes been used when the both parties started out at the same physical location and then separated, each with knowledge of the keys in the one-time pad.The key used in a one-time pad is called a secret key.Ideally destroy the key after use, to make your data to more secure.Key distribution problem led to the invention ofpublic keycryptography.110

PUBLIC KEY CRYPTOGRAPHYPublic-key cryptography, also known asasymmetric cryptography.Requires two separatekey, one of which issecret(orprivate) and one of which ispublic.It has better speed and less complicated then RSA and one time pad .But still there is a problem that is , it can also be hacked.

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QUANTUM KEY DISTRIBUTIONQuantum key distribution(QKD) uses quantum mechanics to guarantee secure communication.Quantum Key Distribution tell us all attempts of eavesdropping.Quantum key distribution is only used to produce and distribute a key, not to transmit any message dataIt enables two parties to produce a shared random bit string known only to them, which can be used as a key for encryption and decryption.

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It is more secure then others schemes.There is a problem that the finest optical fiber have limit of 50 km.

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WHAT IS QUANTUM CRYPTOGRAPHY ?Although the field of cryptography is ancient, but it is not static. Quantum cryptography is a relatively new concept in cryptography.Basically quantum cryptography is combination of OTP and QKD. Quantum cryptography is based on two important principles Polarization of light.Heisenbergs uncertainty principle.114

POLARIZATION OF LIGHT Polarized lightwaves arelightwaves in which the vibrations occur in a single plane.The process of transforming unpolarized light intopolarized lightis known as polarization.Symbols:- Horizontal polarizations Vertical polarization - 45 polarization - 135 polarization -

Fig.4- Polarization of light115

HEISENBERGS UNCERTANITY PRINCIPLEAccording to the principle two interrelated properties cannot be measured individually without affecting the other.The principle is that you cannot partition the photon into two halves without affect it value.So if someone tries to detect the state of photons being send over to the receiver the error can be detected.116

ELEMENT OF QUANTAM CRYPTOGRAPHYLight waves are propagated as discrete quanta called photons.Photons are massless but they have energy, momentum and angular momentum which is called spin.Spin carries the polarization.If on its way we put a polarization filter a photon may pass through it or may not.We can use a detector to check of a photon that has passed through a filter

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QUBITSA quantum bit or qubit is a unit of quantum information.Qubits are not like to simple bits because they have equal possibility.Exists as a 0, a 1 or simultaneously as a superposition of both 0 & 1 .Though the amount of information that can be retrieved in a single qubit is equal to one bit, the difference lies in the processing of information.

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QUANTUM COMMUNICATION

Here the message is send through the public network where as key send is through quantum channel.Fig.5- Quantum communication119

BB84 PROTOCOLBB84 was the first security protocol implementing Quantum Key Distribution.It uses the idea of photon polarization.The key consists of bits that will be transmitted as photons.Each bit is encoded with a random polarization basis!First thing is matter in it that is secure connection.After that the connection is secure and no need to distribution of key again and again,120

Table 1 -Comparing measurementsAlices Bit01011Alices Basis++PhotonBobs Basis+++Bobs Bit00011

The bits allow Alice and Bob to secure the channel for key distribution.

+ + 0 0 1 1

Table 2- Basis value 121

Table 3- Getting the final key basisAs long as no errors and/or eavesdropping have occurred. Alice and Bob have now made sure that the channel is secure.Alices Bit01011Alices Basis++PhotonBobs Basis+++Bobs Bit00011

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The first prototype implementation of quantum cryptography was built at IBM(International Business Machine) on 1989.

Fig.6- First prototype123

ADVANTAGES OF QUANTUM CRYPTOGRAPHYAdvantages of Quantum cryptography is un-hackable.Simple to use.

DISADVANTAGES

Quantum cryptography the signal is currently limited to approx. 50 km. Setup is expensive.

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FUTURE ASPECT Find the another path for key distribution because of the limitation of quantum cable.Make it more secure , so that in future also it cant be hacked.125

CONCLUSIONQuantum cryptography is a major achievement in security engineering.It secure our data transmission as it is never before.Easy to understand and easy to use. As it gets implemented, it will allow perfectly secure bank transactions, secret discussions for government officials, and well-guarded trade secrets for industry.

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REFRENCESMiss. Payal P. Kilor, Mr.Pravin.D.Soni Quantum Cryptography: Realizing next generation information securityISSN 2319 4847,Volume 3, Issue 2, February 2014 pp. 286-289.

Simmon, G. J. ,Symmetric and asymmetric encryption, ISSN 2319 4847,Volume 3, Issue 2, February 2014. pp. 305-330.

Avanindra Kumar Lal, Anju Rani, Dr. Shalini Sharma The New Approach of Quantum Cryptography in Network Security ISSN 2250-2459, Volume 3, Special Issue 2, January 2013 pp.122-126.

G. Ananda Rao a, Muduganti Rathan Reddy A note on Quantum Cryptography, ISSN : 0975-3397 Vol. 4 No. 09 Sep 2012 pp. 1540-1544

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THANK YOU128