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  • 1. Charushila Kadu, Dipti Sonwane, Dheera Jadhwani / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.188-191 How to Avoid Passive Attacks on Data Using BB84 Protocol in Quantum Cryptography: A Review Charushila Kadu, Dipti Sonwane, Dheera Jadhwani Computer Science Department, G.H.Raisoni Institute of Engineering and Management, JalgaonAbstract This paper discuss about new type of key exchange and use of quantum computers are thecryptography known as quantum cryptography. best example of use quantum cryptography.We know that, cryptography is an art of Quantum cryptography gives guarantee to detectconverting data from one form to another one so attacks like eavesdropping in key distribution as trythat it would not be easily known by outside of listening keys disturb complete quantum Many algorithms have been introduced What is the need of quantum cryptography?for converting from plain text to cipher text. Quantum cryptography can transmit aThough there are various secured algorithms are secret key over a long distance which is secure inavailable for encryption, it is very difficult to principle and based on laws of physics. Severalavoid passive attacks on data. Passive attacks are methods of key distribution are available but they allvery dangerous as both parties included in are based on unproven mathematical assumption.communication never know that their These all methods are always on risk of beingcommunication is getting attacked and hence this attacked by the attacker. If you want long-termattack becomes dangerous. Popular example for security, then its really a matter of fact. Quantumpassive attack is eavesdropping which is also now key distribution is known as a subset of quantumas dangerous because if anyone is eavesdropping cryptography which is developed for transferringyour communication, how you will come to know and distributing keys during symmetric encryption.about that? This paper discusses the concept ofquantum cryptography as a solution to this II. TYPES OF QUANTUM CRYPTOGRAPHYattack. A. Post-quantum cryptography Post quantum cryptography refers public –Keywords— quantum cryptography, passive key cryptosystems which cannot be brake byattacks, encryption key, eavesdropping, quantum computers. Basic need behind the evolutionencryption algorithm post quantum cryptography is that most of the popular public cryptographic systems are based onI. WHAT IS QUANTUM CRYPTOGRAPHY? integer factorization problem and discrete We all know that cryptography is a logarithmic algorithm which are easily breakable bytechnique of converting data from one form into large quantum computers using Shorsanother for its safety. Several different algorithms algorithm.[1][2].Though, current availableare implemented for maintains safety of data in experimental quantum cryptography is very secure,cryptography. Use of algorithm get differs from the most of the cryptographers are searching newtype of cryptography we are using for the encryption. algorithms for if quantum cryptography also haveMostly, there are two types of attacks on data in danger form attackers in future. In contrast to this,network. These are active and passive attacks. We symmetric cryptography which is performed byknow that comparative to active attacks; passive symmetric ciphers and hash functions are stillattacks are most dangerous one as parties taking part secured from quantum computers.[2][5] . Thoughin communication don’t aware about something Grover’s algorithm can increase the attacks onhappening wrong with their data. If we know about symmetric cipher text, the danger can be avoided bythe attack (active attack) which is taking place on increasing the size of key used for encryption.our data, we can take some actions against it, but ifwe don’t know that data is being attacked then its B. Position based-quantum cryptographysecurity is naturally under high risk. Then, how to Position based quantum cryptography isavoid passive attacks like release of message content, based on fixed geographical location. Suppose theretraffic analysis? Quantum cryptography is the best are two parties are interested in communication andsolution to overcome this problem. Quantum if they are using position-based quantumcryptography uses quantum mechanical effect to cryptography then one party can send message toencryption or decryption. Quantum mechanical another party only if the other one is at particulareffect includes quantum communication and expected location otherwise data will not bequantum computation. Quantum communication for delivered. How the verification task is performed 188 | P a g e
  • 2. Charushila Kadu, Dipti Sonwane, Dheera Jadhwani / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.188-191then? Basic task of position-verification is that, b) When this horizontally-polarized qubit is passedreceiver has to convince verifier that he is located at through vertically polarizing beam splitter, it alwaysparticular location. This technique is successful gains its horizontal polarization.when there are many restrictions on adversaries.First position-based quantum techniques were c) What happen if the horizonatally-polarizedinvestigated by Kent in 2002 which is known as photon passes through diagonally-oriented beamquantum tagging. A patent for position based- splitter:quantum cryptography known as US-patent [13] wasgranted in 2006, and scientific literature published  There are 50% chances of finding theresults in 2010.[14] Several position-based quantum photon at one of the exit.cryptography protocols have been suggested mostly  Photon will detect at one of the exit.using quantum entanglement.  The polarization of photon will changed into the corresponding diagonal polarization.III. QKD AND QUBITS Expected output for the step c is photon will be Quantum key distribution is most well blocked and not passed through and it will changeknown and developed application of quantum polarization. Polarized photon will convey digitalcryptography which is also known as QKD. QKD information, details of which are shown in Fig.2.explain the process of using quantum cryptographyfor distributing key between two parties taking partin communication without disturbing third party. Ifthese parties are communicating with each other andif third party try to eavesdrop the content, thencomplete bit pattern may get disturbs. Security of quantum key distribution can beeasily proved without imposing any type ofrestriction on eavesdropper which is not possible byusing classical cryptography, which is known as“unconditional security”. But there may be chancesof man-in-middle-attacks if eve becomes able toimpersonate Alice or Bob. Quantum cryptography iscommercially available in the form of QKD only.Basic unit of quantum information is quantum bitknown as qubit. Value of the quantum bit is taken asits polarization as value of classical bit can be takenas 0 or 1 only. Fig. 2 polarized photons conveying digitalA. Quantum properties information As we know that digital systems use binarystates like one/zero, on/Off or Yes/No, what is the B. BB84 Protocolstate of quantum bit? Qubit is considered as single BB84 protocol is the first quantumphoton and its manipulation is shown in Fig 1. cryptographic protocol discovered by Charles H. Bennet of IBM New York and Gilles Brassard of the University of Montreal in 1984.This protocol is based upon the technique of generation of secretes keys for encryption and decryption. This is implemented in different technologies which are as follows.  Single Photon polarization  Two Photon entanglements  Single photon Self interference phase modulationFig. 1 qubit and single Photon Here we will how BB84 protocol works for single photon polarization is discussed.a): A photon is emitted from light source and passes .through linear polarizer, here we consider horizontal  Alice will create photon by single photonpolarizer. This process will create qubit with from light source.horizontal polarization. 189 | P a g e
  • 3. Charushila Kadu, Dipti Sonwane, Dheera Jadhwani / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.188-191 Then, photon will send through polarizer Different cryptographic tasks such as encryption,and naturally it gives one of the possible polarization transmission and decryption of data is performed byout of four one. They are as Horizontal (Zero bit), various conventional tools over standardVertical (One bit), 45 degree left (Zero bit), 45 communication network so far secrete key protocolsdegree right (One bit). are implemented. By keeping encryption key secrete Then, photon starts travelling towards or documental secured, optimal data security isBob’s location. achieved. This is the way how data is encrypted with At receiver end, bob will be having two randomly generated key. This type of databeam splitters a vertical/horizontal and diagonal and encryption never containing unique patterns of itselftwo photon detectors. which can be used for code breaking. Bob will randomly choose one of the twosplitter and check photon detectors. E. Eavesdropping Detection Same process is repeated until the complete When third party try to listen your data onkey will be transmitted to the Bob. quantum channel, all the sequences of qubit get Then, Bob will inform Alice about the disturbed. Suppose, Eve listens the qubits, then hebeam splitter he have been used. will send bits to Bob with his listening. If all the bases used by the Eve are different then Then Alice will compare the informationwith the different sequence of polarizes that are used measurements will go wrong. Hence, eavesdroppingby her to send the key. can be easily detected in quantum cryptography. As we know that, avoiding passive attacks are very Alice will inform Bob where there is use important to maintain the security of your data.the right beam splitter in the sequence of bit. Quantum cryptography definitely provides you a Finally both Alice and Bob know key used very proper way of keeping your data safe fromin communication between them. eavesdropper.It is quite best method of exchanging key. REFERENCESC. Working Principle of BB84 Protocol [1] "Cerberis Encryption Solution - Layer 2 First Alice will transmit a random sequence Encryption with Quantum Keyof qubits to Bob over a quantum channel. this Distribution". id Quantique.sequence is generated by her by repeatedly encoding randomly selected bit with two selected base from encryption/cerberis-layer2-encryption-and-two different bases. It also results in random qkd.html. Retrieved 1 march 2012sequence of four selected quantum states. Base- [2] "Products". MagiQ.value –combinations was recorded by Alice which is during generation in future. The two bases are s.html. Retrieved 1 march 2012.applied for encoding and decoding. But they should [3] Crépeau, Claude; Joe, Kilian (1988).yield correct result when aligned and produced. "Achieving Oblivious Transfer Using Weakened Security Assumptions (ExtendedD. Key generation Abstract)". FOCS 1988. IEEE. pp. 42–52 Bob receives the qubits directly from Alice [4] Joe, Kilian (1988). "Founding cryptographywhen not intercepted. As Alice only transmits qubit on oblivious transfer". STOC 1988. ACM.without any information, Bob has to derive the pp. 20–31.information from the qubits through randomly sequence through its own base. If the bases ollected-papers/ by Bob match with the sequence at the time [5] Gilles, Brassard; Crépeau, Claude; Richard,of encoding, then the result is considered as correct. Jozsa; Langlois, Denis (1993). "A QuantumBob will record the sequence of his own bases and Bit Commitment Scheme Provablythe different measurement of result made by him. Unbreakable by both Parties". FOCS 1993. IEEE. pp. 362–371. Then Bob and Alice will communicate with [6] Mayers, Dominic (1997). "Unconditionallyeach other to compare their bases sequences. Only Secure Quantum Bit Commitment isthe value which is used for encoding and decoding Impossible". Physical Review Letters (APS)key by them, while other bits are removed from the 78 (17): 3414–3417. arXiv:quant-sequences. The remaining sequence is nothing but ph/9605044. Bibcoderandom private key which is also known as sifted 1997PhRvL..78.3414M.key. As this raw key is not enough suitable for using doi:10.1103/PhysRevLett.78.3414. Preprintencryption and decryption, it is used for generating at arXiv:quant-ph/9605044v2another key which will be used to perform different [7] Mayers, Dominic (1997). "Unconditionallyquantum cryptographic task on data. Secure Quantum Bit Commitment is Impossible". Physical Review Letters (APS) 190 | P a g e
  • 4. Charushila Kadu, Dipti Sonwane, Dheera Jadhwani / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol. 2, Issue 6, November- December 2012, pp.188-191 78 (17): 3414–3417. arXiv:quant- security from noisy quantum storage".A ph/9605044. Bibcode full version is available at arXiv: 0906.1030. 1997PhRvL..78.3414M. [11] Koenig, Robert; Wehner, Stephanie; doi:10.1103/PhysRevLett.78.3414. Preprint Wullschleger, Juerg. "Unconditional at arXiv:quant-ph/9605044v2 security from noisy quantum storage".A[8] Damgård, Ivan; Fehr, Serge; Salvail, Louis; full version is available at arXiv:0906.1030 Schaffner, Christian (2005). "Cryptography [12] Cachin, Christian; Crépeau, Claude; Marcil, In the Bounded Quantum-Storage Model". Julien (1998). "Oblivious Transfer with a FOCS 2005. IEEE. pp. 449–458. A full Memory-Bounded Receiver". FOCS 1998. version is available at arXiv:quant- IEEE. pp. 493–502. ph/0508222. [13] Dziembowski, Stefan; Ueli, Maurer (2004).[9] Wehner, Stephanie; Schaffner, Christian; "On Generating the Initial Key in the Terhal, Barbara M. (2008). "Cryptography Bounded-Storage Model". LNCS. 3027. from Noisy Storage". Physical Review Eurocrypt 2004. Springer. pp. 126–137. Letters (APS) 100 (22): 220502. Preprint available at [1]. arXiv:0711.2895. Bibcode [14] Chandran, Nishanth; Moriarty, Ryan; Goyal, 2008PhRvL.100v0502W. Vipul; Ostrovsky, Rafail (2009). Position- doi:10.1103/PhysRevLett.100.220502. Based Cryptography. A full version is PMID 18643410. available at IACR eprint:2009/364. [15] Kent, Adrian; Munro, Bill; Spiller, Tim 02. A full version is available at (2010). "Quantum Tagging with arXiv:0711.2895 Cryptographically Secure Tags". A full[10] Koenig, Robert; Wehner, Stephanie; version is available at arXiv:1008.2147 Wullschleger, Juerg. "Unconditional 191 | P a g e