24 th IEEE Annual Computer Communications Workshop (CCW)

Transcription

1 24 th IEEE Annual Computer Communications Workshop (CCW) Exploration of Quantum Cryptography in Network Security Presented by Mehrdad S. Sharbaf Sharbaf & Associates Loyola Marymount University California State University Northridge

2 24 th IEEE Annual Computer Abstract Threats and attacks to information systems security on digital network environment are growing rapidly, putting pressure on businesses to protect their tangible and intangible assets. It is reported that 75% of surveyed organizations have confronted different network security attacks. For that reason, cryptography is a vital of today s computer and communications networks, protecting everything from business to bank transactions and internet shopping.

3 24 th IEEE Annual Computer Abstract But the scholars argue that, the current encryption algorithms based on mathematical model introduce potential security holes related to the key refresh rate and key expansion ratio, the most crucial parameters in the security of any cryptographic techniques. These cryptographic techniques are widely used but are not proved to be completely secure, representing one of the main threats to modern network communication systems. For past decade efforts have been made to establish new foundation for cryptography science in the computer communications networks. One of these efforts has led to the development of quantum cryptography technology, whose security relies on the laws of quantum mechanics.

4 24 th IEEE Annual Computer Topics 1. Understand the goals of network security 2. Determine the factors involved in a secure network strategy 3. Understand the basics of algorithms and how they are used in modern cryptography 4. Identify the differences between asymmetric and symmetric algorithms 5. Vulnerabilities/Weakness to the modern/classical cryptography 6. Understanding of the quantum cryptography 7. QKD protocol 8. Implementation of quantum cryptography 9. Vendors/Products/Research group 10. Summary /Q & A

5 24 th IEEE Annual Computer Understand the goals of network security Network security It is a process by which digital information assets are protected Goals Maintain integrity (data( is not altered or destroyed ) Protect confidentiality (Protection( of data from unauthorized ) Assure availability (Continuous( operation of network)

6 24 th IEEE Annual Computer Determine the factors involved in a secure network strategy Analysis both internal and external threats Define & enforce policies and procedures Reduce risk across perimeter security, the Internet, intranets, Extranet, and LANs Human factors Risk Assessment (Know your weakness) Limit access Achieve security through continuous process Remember physical security

7 24 th IEEE Annual Computer Determine the factors involved in a secure network strategy Firewalls Access Control (Only legitimate traffic) Management process to security issues Cryptography (Encryption/Decryption) IDS (Intrusion Detection Systems)

8 24 th IEEE Annual Computer Moore s Law and Quantum Physics

9 24 th IEEE Annual Computer Moore s Law and Quantum Physics The semiconductor industry realized that the improvement of computers according to Moor s law would all too soon reach the quantum limit, requiring radical changes in technology

10 24 th IEEE Annual Computer Understand the basics of algorithms and how they are used in modern cryptography Mathematical functions that work in tandem with a key Same plaintext data encrypts into different cipher-text with different keys Security of data relies on two factors: Strength of the algorithm Secrecy of the key

11 24 th IEEE Annual Computer Symmetric Algorithm Usually use same key for encryption and decryption Encryption key can be calculated from decryption key and vice versa Require sender and receiver to agree on a key before they communicate securely Security lies with the key Also called secret key algorithms, singlekey algorithms, or one-key algorithms Example: DES (1977), Triple DES (1998), AES

12 24 th IEEE Annual Computer Symmetric Algorithm

13 24 th IEEE Annual Computer Asymmetric Algorithm Use different keys for encryption and decryption Decryption key cannot be calculated from the encryption key Anyone can use the key to encrypt data and send it to the host; only the host can decrypt the data Also known as public key algorithms Example: Diffie-Hellman (1976) RSA (1977)

14 24 th IEEE Annual Computer Asymmetric Algorithm

15 Identify the differences between symmetric and asymmetric algorithm Type of algorithm Advantage Disadvantages Symmetric Single key Requires sender and receiver to agree on a key before transmission of data Security lies only with the key High cost Asymmetric Encryption and decryption keys are different Decryption key cannot be calculated from encryption key Security of keys can be compromised when malicious users post phony keys

16 Vulnerabilities/Weakness to the modern/classical cryptography Current encryption algorithms based on mathematical model introduce potential security holes related to the key refresh rate and key expansion ratio. There are three main problems with encryption schemes. The first is key distribution, which must be in itself, the second is key management, where the number of keys required in a system with a large number of principals does not scale well. Thirdly as computing power increases, and new classical computational techniques are developed, the length of time that a message can be considered secure will decrease, and numerical keys will no longer be able to provide acceptable levels of secure communications

17 Vulnerabilities/Weakness to the modern/classical cryptography Vulnerable to the progress in computation (supercomputers) and algorithms. Vulnerable to future quantum computation protocols. For example: Shor s Algorithm (Peter Shor): Factoring Allows for factoring large numbers on a quantum computer in polynomial time, theoretically breaking RSA encryption. While any practical application on Shor s algorithm may be decade away, but an experimental proof-of-concept of Shor s algorithm has successfully been achieved.

18 Understanding of the quantum cryptography For past decade efforts have been made to establish new foundation for cryptography science in the computer communications networks. One of these efforts has led to the development of quantum cryptography technology, whose security relies on the laws of quantum mechanics. Quantum cryptography concept developed by Charles H. Bennett and Gilles Brassard in 1984 (BB84) as part of research study between physics and information at IBM lab. The quantum system is based on the distribution of single particles or photons, and the value of a classical bit encodes by the polarization of a photon.

19 Photons A photon is an elementary particle of light, carrying a fixed amount of energy. Based on physical law, light may be polarized; polarization is a physical property that emerges when light is regarded as an electromagnetic wave. The direction of a photon s polarization can be fixed to any desired angle (using a polarizing filter) and can be measured using a calcite crystal.

20 Understanding of the Quantum cryptography In fact, the quantum cryptography relies on two important elements of quantum mechanics-the Heisenberg Uncertainty principle and the principle of photon polarization. The Heisenberg Uncertainty principle states that, it is not possible to measure the quantum state of any system without distributing that system. This means, the polarization of a photon or light particle can only be known at the point when it is measured. Secondly, the photon polarization principle explains how light photons can be polarized in a specific direction. In addition, an eavesdropper can not copy unknown qubits i.e. unknown quantum states, due to no-cloning theorem which was first presented by Wootters and Zurek in 1982.

21 Photons Polarization A photon has a property called polarization, which is the plane in which the electric field oscillates. We can use photons of different polarizations to represent quantum states. Each of these photons is in a state denoted by one of the four following symbols:,, /, \ The first two photon states are emitted by a polarizer which is set with a rectilinear orientation and the other two states are emitted by a polarizer which is set with a diagonal orientation. In order to communicate, a coding system is necessary. State codes 1, while codes 0, and State / codes 0, while \ codes 1. +(0)=, +(1)=, x(0)= /, x(1)= \

22 Photons Polarization For example: If Alice wants to transmit the conventional bit 0 or 1, she may choose to use + and consequently send out over the quantum channel,, or choose to use x and consequently send out /, \ If Alice is sending only and to Bob, the coding system shall identify that Alice is using the base +. For example, if Alice sends sequence of photons:,,, ; the binary number represented with these states is Now, if Bob wants to obtain a binary number sent by Alice, he needs to receive each photon in the same basis. In this case, this is + basis

23 Photons Polarization A device called a polarizer allows us to place a photon in a particular polarization. A Pockels Cell can be used too. The polarization basis is the mapping we decide to use for a particular state. Rectilinear: Diagonal: 0 state 0 45 state 0 90 state state 1

24 Photons Polarization Ultra-Miniature Pockels Cells Double Pockels Cells Single and Dual Crystal Pockels Cells

25 Measuring Photons A calcite crystal can be used to recover the bits encoded into a stream of photons. CaCO3 DIAGONA L axis

26 QKD Protocols A protocol is a set of rules governing the exchange of messages over a channel. A security protocol is a special protocol designed to ensure security properties are met during communications. There are three main security protocols for QKD: BB84, B92, and Entanglement-Based QKD. We will only discuss BB84 in this session.

27 BB4 Protocol BB84 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!

28 BB4 Protocol

29 BB4 Protocol with No Eve (No eavesdropping) Alice is going to send Bob a random key. She begins with transmitting a random sequence of bits. Bits are encoded with a random basis, and then sent to Bob: Bit Basis + + Photon

30 BB4 Protocol with No Eve (No eavesdropping) Bob receives the photons and must decode them using a random basis. Some of his measurements are correct. Photon Basis? Bit?

31 BB4 Protocol with No Eve (No eavesdropping) Alice and Bob talk on the telephone: Alice chooses a subset of the bits (the test bits) and reveals which basis she used to encode them to Bob. Bob tells Alice which basis he used to decode the same bits. Where the same basis was used, Alice and Bob agree on the bits.

32 Alice s Bit Alice s Basis + + Bob s Basis Bob s Bit Photon Test bits discarded Final Key = 01

33 BB4 Protocol with Eve (In the presence of eavesdropping) If an eavesdropper Eve tries to tap the channel, this will automatically show up in Bob s measurements. In those cases where Alice and Bob have used the same basis, Bob is likely to obtain an incorrect measurement(error Rate). Eve s measurements are bound to affect the states of the photons.

34 BB4 Protocol with Eve (In the presence of eavesdropping) As Eve intercepts Alice s photons, she has to measure them with a random basis and send new photons to Bob. The photon states cannot be cloned (no-cloning theorem which was first presented by Wootters and Zurek in Eve s presence is always detected: measuring a quantum system irreparably alters its state (The Heisenberg Uncertainty principle).

35 QKD Protocol Implementation (Key DistillationDistillation-Realistic Case)

36 QKD Protocol Implementation (Key DistillationDistillation-Realistic Case) Sifting is the process whereby Alice and Bob window away all the obvious failed qubits from a series of pulses. Sifting allows Alice and Bob reconcile their raw secret bit streams to remove the errors. Error detection and correction allows Alice and Bob to determine all the error bits among their shared, sifted bits, and correct them so that Alice and bob share the same sequence of error-corrected bits. The process of error detection allows Alice and Bob to estimate the current Quantum Bit Error Rate (QBER) on the quantum channel between them, which can then be used as input for privacy amplification.

37 QKD Protocol Implementation (Key DistillationDistillation-Realistic Case) Privacy Amplification is the process whereby Alice and bob reduce Eve s knowledge of their shared bits to an acceptable level. Authentication allows Alice and Bob to guard against man in the middle attack, i.e. allows Alice to ensure that she is communicating with Bob (and not Eve) and vice versa.

38 Implementing Quantum Cryptography (Real Cases) DARPA, The Bank Austria Creditanstalt, Creditanstalt, & Japan BBN, Harvard, and Boston University built the DARPA quantum network, the world s first network that delivers end-to-end network security via high-speed quantum key distribution, and tested that network against sophisticated eavesdropping attacks. This network allows users at BBN Technologies, Harvard University, and Boston University to tap into a fiber-optic loop secured by a quantum cryptography system.

39 Implementing Quantum Cryptography (Real Cases) DARPA, The Bank Austria Creditanstalt, Creditanstalt, & Japan For the Bank of Austria, the novel technology was demonstrated by the group of Professor Anton Zeilinger, Vienna University in collaboration with the group Quantum Technologies of Seibersdorf research. The bank transfer was initiated by Vienna s Mayor Dr. Michael Haupl, and executed by the director of the Bank Austria Creditanstalt, Dr. Erich Hampel. The information was sent via a glass fiber cable from the Vienna City Hall to the Bank Austria Creditanstalt branch office Schottengasse.

40 Implementing Quantum Cryptography (Real Cases) DARPA, the Bank Austria Creditanstalt, Creditanstalt, & Japan Mitsubishi Electric Corporation, NEC Corporation, and Institute of Industrial Science, University of Tokyo have successfully interconnected quantum cryptography systems developed by Mitsubishi Electric and NEC, the first time such an experiment has been successful in Japan.

41 Vendors, Products, & Research Group MagiQ Technologies, Inc. (USA) IdQuantique (Switzerland) NEC (Japan) Research Groups working on QKD at IBM and Toshiba (USA, Europe) Japan Research Group 01.html NIST Research Group

42 Vendors & Products QPN 7505 Up to 100 km

43 Vendors & Products

44 TECHNICAL CHALLENGES OF QKD AND FUTURE DIRECTION One of the challenges for the researchers, is distance limitation. Currently, quantum key distribution distances are limited to tens of kilometers because of optical amplification destroys the qubit state. Also to develop optical device capable of generating, detecting and guiding single photons; devices that are affordable within a commercial environment. Another issue is the lack of a security certification process or standard for the equipment. Also users need reassurance not only that QKD is theoretically sound, but also that it has been securely implemented by the vendors.

45 Summary Realization of practical quantum information technologies can not be accomplished without involvement of the network research community. The advances in computer processing power and the threat of limitation for today s cryptography systems will remain a driving force in the continued research and development of quantum cryptography. The technology has the potential to make a valuable contribution to the network security among government, businesses, and academic environment.

46 Thank You Q&A