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

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

5. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions 1.In conventional data transmission every bit has a definite value of 0 or 1. 2.Linearly polarized atomic particles can be used as data bits for quantum data transmission. 3.Qubits can change their state when measured. 4.Linear polarized photons are natural qubits. 5.Qubits are extremely delicate. Quantum bits (Qubits)

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

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

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

9. Background Alice’s Receiving Filters Key 1111 Current Encryption Quantum Mechanics Quantum Encryption LimitationsPredictions Bob’s Values 0 1 1 1 0 1 1 0 Alice’s Measured Values 1 1 1 1 1 1 1 0 Encryption Example Bob’s Sending Filters 01 0 1 Bob Confirms Correct Filters  

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

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

12. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Shannon’s Secure Cryptography Equation 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. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Quantum Encryption Problems 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. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations Predictions Specific Application Encryption 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. Background Current Encryption Quantum Mechanics Quantum Encryption Limitations PredictionsReferences 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.pdfhttp://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.htmlhttp://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_cry pto_demoed_112702.htmlhttp://www.trnmag.com/Stories/2002/112702/Fast_quantum_cry pto_demoed_112702.html