08-08-2012, 02:58 PM
QUANTUM CRYPTOGRAPHTY
QUANTUM CRYPTOGRAPHTY.pptx (Size: 2.03 MB / Downloads: 32)
CRYPTOGRAPHY
Cryptography is the process of converting ordinary information called plaintext into unintelligible gibberish called cipher text
Decryption is the reverse, in other words, moving from the unintelligible cipher text back to plaintext.
The detailed operation of a cryptography is controlled both by the algorithm and in each instance by a "key".
QUANTUM MECHANICS
Spawned during the last century
Branch of physics that Describes properties and interaction between matter
Quantum state of a system is determined by
Positions
Velocities
Polarizations
Spin
Qubits - quantum bit is a unit of quantum information
Quantum states are used to represent binary digits 0 and 1.
One could for example use the spin of a particle and let UP-spin to be zero and DOWN-spin to be one and vice versa.
Existing cryptographic methods
Existing cryptographic methods include the
Public key cryptography and the private key cryptography
The existing cryptography methods use algorithm and mathematical calculations to generate the key
Transmission of data via classical channel
DRAWBACKS
Existing key distribution methods are vulnerable to impersonation
Cannot detect the presence of an intruder
Noisy channels may disrupt the transmission
The size of the key is very large
These keys can be easily decoded using mathematical formulas or using a Quantum computer
Overview of Quantum cryptography
Quantum cryptography is based on the principle of Quantum mechanics
The Quantum cryptography uses QUBITS to transmit the data over a optic fiber channel
The data that has to be transmitted is sent as a photon this photon is called as a QUBIT
Quantum cryptography can detect the presence of a intruder trying to intercept the information
Quantum cryptography uses BB84 protocol
Key distribution – BB84
The key distribution takes place over a Quantum channel and a Classic channel
sender prepares photons randomly with either rectilinear or circular polarizations and sends it
receiver receives each photon and randomly measures its polarization according to the
rectilinear or circular basis.
He records the measurement type (basis used) and the resulting polarization measured.
The polarization sent by sender may not be the same polarization receiver finds if he does not use the same basis as sender.
receiver publicly tells sender what the measurement types were, but not the results of the measurements.
sender publicly tells receiver which measurements were of the correct type.
sender and receiver each throw out the data from measurements that were not of the correct type
Conclusion
Information can be transmitted securely
Even if a intruder tries to eves drop the qubits there is a high possibility of not cracking the information
The ability to detect eavesdropping ensures secure exchange of the key
Equipment can only be used over short distances
Equipment is complex and expensive
QUANTUM CRYPTOGRAPHTY.pptx (Size: 2.03 MB / Downloads: 32)
CRYPTOGRAPHY
Cryptography is the process of converting ordinary information called plaintext into unintelligible gibberish called cipher text
Decryption is the reverse, in other words, moving from the unintelligible cipher text back to plaintext.
The detailed operation of a cryptography is controlled both by the algorithm and in each instance by a "key".
QUANTUM MECHANICS
Spawned during the last century
Branch of physics that Describes properties and interaction between matter
Quantum state of a system is determined by
Positions
Velocities
Polarizations
Spin
Qubits - quantum bit is a unit of quantum information
Quantum states are used to represent binary digits 0 and 1.
One could for example use the spin of a particle and let UP-spin to be zero and DOWN-spin to be one and vice versa.
Existing cryptographic methods
Existing cryptographic methods include the
Public key cryptography and the private key cryptography
The existing cryptography methods use algorithm and mathematical calculations to generate the key
Transmission of data via classical channel
DRAWBACKS
Existing key distribution methods are vulnerable to impersonation
Cannot detect the presence of an intruder
Noisy channels may disrupt the transmission
The size of the key is very large
These keys can be easily decoded using mathematical formulas or using a Quantum computer
Overview of Quantum cryptography
Quantum cryptography is based on the principle of Quantum mechanics
The Quantum cryptography uses QUBITS to transmit the data over a optic fiber channel
The data that has to be transmitted is sent as a photon this photon is called as a QUBIT
Quantum cryptography can detect the presence of a intruder trying to intercept the information
Quantum cryptography uses BB84 protocol
Key distribution – BB84
The key distribution takes place over a Quantum channel and a Classic channel
sender prepares photons randomly with either rectilinear or circular polarizations and sends it
receiver receives each photon and randomly measures its polarization according to the
rectilinear or circular basis.
He records the measurement type (basis used) and the resulting polarization measured.
The polarization sent by sender may not be the same polarization receiver finds if he does not use the same basis as sender.
receiver publicly tells sender what the measurement types were, but not the results of the measurements.
sender publicly tells receiver which measurements were of the correct type.
sender and receiver each throw out the data from measurements that were not of the correct type
Conclusion
Information can be transmitted securely
Even if a intruder tries to eves drop the qubits there is a high possibility of not cracking the information
The ability to detect eavesdropping ensures secure exchange of the key
Equipment can only be used over short distances
Equipment is complex and expensive