Download - Quantum Cryptography
![Page 1: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/1.jpg)
Shyam MohanS4 – MCANO: 43College of Engineering,Trivandrum
![Page 2: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/2.jpg)
OUTLINE• Basics of Cryptography• Basics of Quantum Computing• Need for Quantum Cryptography• Implementation of Quantum Cryptography• Quantum Key Distribution protocol BB84• BB84 with Eavesdropping• Research and Innovation• Conclusion• Interaction
1/10
![Page 3: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/3.jpg)
Basics of Cryptography• Cryptography is the coding and decoding of secret messages
• Cryptanalysis is the art of interpreting cipher text
• Key is only known to the sender and receiver
2/10
Plain text like“Hello”
Cipher Text-.h7ib.v84%t9n
“Hello”ENCRYPTIONKEY KEY
DECRYPTION
![Page 4: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/4.jpg)
Basics of Quantum Computing
• Quantum computers use quantum bits (QUBITS)• n bits can represent only one state from 2n possible states• n qubits can represent 2n quantum states simultaneously• A single qubit can represent 1 or 0 like a bit
3/10
![Page 5: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/5.jpg)
Need of Quantum Cryptography
• Bits in classical cryptography can be copied anonymously• Quantum computer can use Shor’s algorithm to break RSA encryptions• Commercial Quantum Computers by D-Wave • QuAIL (Quantum Artificial Intelligence Lab ) set up by NASA, Google, and
the Universities Space Research Association (USRA)• Unknown qubits cannot be accessed and copied like bits without changing
its values (Non-cloning quantum theorem)
4/10
![Page 6: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/6.jpg)
Implementation of Quantum Cryptography
• Implemented by using optical fiber cables which act as a quantum channel
• Or can be implemented aerially using laser and satellites
5/10
![Page 7: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/7.jpg)
Quantum Key Distribution protocol BB84
• BB84 - the security protocol for implementing Quantum Key Distribution(QKD)• It uses the idea of Photon polarization• Photons are used to represent single qubits (1,0)
6/10
![Page 8: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/8.jpg)
Steps in BB84 Protocol
7/10
• Step 1 : Sender transmits a random sequence of 1’s and 0’s ( bits),which is converted into photon states by randomly using rectilinear and diagonal polarisation schemes .
• Step 2 : Receiver randomly interprets the photon states by randomly using his rectilinear and diagonal detectors
• Step 3 : Receiver sends information about sequence of detectors used randomly over a classical channel.
![Page 9: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/9.jpg)
Steps in BB84 Protocol (contd..)
7/10
• Step 4 : Sender in return tells the matching polarisation scheme guessed by receiver.
• Step 5 : Sender and receiver eliminates the unmatched interpretations and use the remaining binary equivalent as the key.
![Page 10: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/10.jpg)
BB84 with Eavesdropping
8/10
![Page 11: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/11.jpg)
BB84 with Eavesdropping
8/10
• Retained bit sequence (KEY) : 001110010100110• Confirms some randomly chosen bit values over classical channel like Internet or
telephone : 001110010100110
If no eavesdropping happened, the values will be same for both Alice and Bob. Then they drop the confirmed bits and uses the rest as
FINAL KEY: 01100101010Else if any mismatch occurs, eavesdropping is confirmed and current key generation is cancelled.
![Page 12: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/12.jpg)
9/10
Research and Developments• Tokyo Quantum Key Distribution Network deployed in October
2010
• Toshiba Quantum Key Distribution Network deployed exceeding 100 km in length
• Swiss Quantum Key Distribution Network in Geneva metropolitan area
• QC based voting machine developed by Id Quantique, is used in the Swiss canton of Geneva during the October 2007 parliamentary elections.
![Page 13: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/13.jpg)
In a Nutshell• Quantum cryptography (or quantum key distribution) is a state-of-the-art
technique that exploits the properties of quantum mechanics to guarantee the secure exchange of secret keys.
10/10
![Page 14: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/14.jpg)
Interaction , Discussion , Analysis
What… ? Why? How ?
Who ?Can We…?
why can't ?Why not ?
![Page 15: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/15.jpg)
![Page 16: Quantum Cryptography](https://reader036.vdocuments.net/reader036/viewer/2022062822/587b908c1a28ab4e4f8b50a1/html5/thumbnails/16.jpg)
ALL