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Single Photon Quantum Encryption

Single Photon Quantum Encryption. Rob Grove April 25, 2005. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions. Telephone Internet Courier In person. Bob needs to get a secure message to Alice. Private Key Cryptography. Background

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Single Photon Quantum Encryption

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  1. Single Photon Quantum Encryption Rob Grove April 25, 2005

  2. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions • Telephone • Internet • Courier • In person Bob needs to get a secure message to Alice

  3. Private Key Cryptography Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Private Key Encrypt/Decrypt Private Key Encrypt/Decrypt Private Key Bob Alice • Private key encryption uses permutations and other reversible mathematical operations to encode the message. Eve

  4. Public Key Cryptography Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Public Key Encrypt Private Key Decrypt Encrypted Message Bob Alice Public Key • Public key encryption uses prime multiplication and other very hard to reverse mathematical operations to encode the message. Eve

  5. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions • In conventional data transmission every bit has a definite value of 0 or 1. • Linearly polarized atomic particles can be used as data bits for quantum data transmission. • Qubits can change their state when measured. • Linear polarized photons are natural qubits. • Qubits are extremely delicate. Quantum bits (Qubits)

  6. Polarization of Photons Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions

  7. Wave Polarization Circular Polarization Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Linear Polarization

  8. Polarizing Filters Polarized at 45 degrees Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Filters can be used to measure photon polarization Filters can be used to polarize photons into qubits for data transmission

  9. 0 0 1 Bob’s Sending Filters 1 Bob’s Values 0 1 1 1 0 1 1 0 Alice’s Receiving Filters Alice’s Measured Values 1 1 1 1 1 1 1 0 P P P P Bob Confirms Correct Filters 1 1 1 1 Key Encryption Example Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions

  10. Method 2. Alice generates one random sequence and uses it to filter Bob’s data. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Alice’s Filter Bob Bob’s Filter 100101010001 110011000100 010111100111 1. Bob generates two random number sequences. Alice Subset of Bob’s Key 3. Alice tells Bob her filter sequence and Bob tells her which ones are wrong.

  11. Quantum Encryption Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Key Bob Alice Introduces gross error > 25% Eve

  12. Shannon’s Secure Cryptography Equation Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions The only way this can happen is if a totally random key of equal length to the message is XOR’d with the message.

  13. Quantum Encryption Problems Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions • Restricted to fiber-optics cable • Greatest distance proven is under 62 miles • Hardware is expensive • Individual photons have not been demonstrated • Data throughput is not very high, 1~10 kb / s

  14. Specific Application Encryption Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions • Will not be a substitute for public key encryption for most applications • Will not directly impact 99% of internet users • Will be a useful tool against massive internet attacks on back bone structure • Will be a solution for line of sight business encryption

  15. References • http://www.wsi.tum.de/E24/research/spintronics/spintronics.htm • http://www.mycrypto.net/encryption/crypto_algorithms.html • http://www.tryagain.com/humcivil/qntmencr.htm • http://www.idquantique.com/files/introduction.pdf • http://www.cs.jhu.edu/~scheideler/courses/600.471_S03/lecture_6.pdf • http://www.cs.dartmouth.edu/~jford/crypto.html • http://www-theory.chem.washington.edu/~trstedl/quantum/quantum.html • http://scienceworld.wolfram.com/physics/WaveEquation.html • http://www.wordless.com/CGI/article.asp?ArticleId=21 • http://www.mtnmath.com/whatrh/node78.html • http://www.th.physik.uni-frankfurt.de/~jr/physpicquant.html • http://www.trnmag.com/Stories/2002/112702/Fast_quantum_crypto_demoed_112702.html Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions

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