QUANTAM CRYPTOGRAPHY
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Transcript of QUANTAM CRYPTOGRAPHY
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QUANTAM CRYPTOGRAPHY
-SECRECY ENSURED
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TABLE OF CONTENT
TECHNOLOGYKEY DISTRIBUTUION
CLASSICAL CRYPTOGRAPHY
QUANTAM CRYPTOGRAPHY
WORKING
INTRODUCTION
SECURITY
CONCLUSION
ADVANTAGES LIMITATIONS
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INTRODUCTION The recent application of the principles
of quantum mechanics to cryptography has led to a remarkable new dimension in secret communication.
Quantum cryptography is an effort to allow two users of a common communication channel to create a body of shared and secret information.
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CRYPTOGRAPHY The whole point of cryptography is to
keep information out of the hands of anyone but its intended recipient.
Even if the message gets intercepted, the meaning won’t be apparent to the intercepted – unless the interceptor is able to decipher it.
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Principle of Cryptography.
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A PRACTICAL EXAMPLE -
Alice wants to send a message to Bob, without an eavesdropper Eve intercepting the message.
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TYPE OF CRYPTOGRAPHY
CRYPTOGRAPHY
Classical Quantum
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THE CLASSICAL CRYPTOGRAPHY Encryption algorithm and related
key are kept secret. Breaking the system is hard due to
large numbers of possible keys.
For example: for a key 128 bits long there are – keys to
check.38128 102
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THE QUANTUM CRYPTOGRAPHY An important and unique property of
quantum cryptography is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key.
Quantum technology promises to revolutionize secure communication at an even more fundamental level.
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THE QUANTUM CRYPTOGRAPHY Quantum Cryptography – ensuring the most
secure transmission of the secret information – works on the principle of – “ Quantum Mechanics”.
Transmission is carried out at the bit level with the help of various types of alignment of the photons.
It also solves the problem of key distribution arising in the Classical Cryptography.
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WORKING
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QUANTUM KEY DISTRIBUTION A user can suggest a key by sending a
series of photons with random polarizations. This sequence can then be used to generate a sequence of numbers. The process is known as quantum key distribution.
Main Features: Key distribution distance: up to 60 km Key distribution rate: up to 1000 bits/s
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QUANTUM CRYPTOGRAPHY TECHNOLOGY
Photon Source.
Photon Detector.
Communication channel.
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PHOTON SOURCE
Photon Gun.
Light - emitting p-n junction.
Single ion.
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PHOTON DETECTOR
Avalanche photodiodes.
Germanium detectors.
Silicon.
Photo multiplier.
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COMMUNICATION CHANNEL
Fiber optical communication link.
Free – space laser communication.
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SECURITY OF QKD Quantum cryptography obtains its
fundamental security from the fact that each qubit of information is carried by a single photon, and that each photon will be altered as soon as it is read once.
This makes impossible to intercept message without being detected.
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EFFECT OF NOISE The presence of noise can impact
detecting attacks. Eavesdropper and noise on the
quantum channel are indistinguishable.
Detecting eavesdropper in the presence of noise is hard.
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APPLICATION
E-mail messages. Telephone calls. Financial Transactions.
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ADVANTAGES
The most important contribution of quantum cryptography is a mechanism for detecting eavesdropping.
Quantum key distribution enables “encrypted communications on demand,” because it allows key generation at transmission time over an unsecured optical communications link.
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LIMITATIONS We have to use pure fiber optic end-to-end
network and boosters are needed at some distance, so it is expensive.
It will also be critical to authenticate the identity of the recipients.
It is also not clear how to modify the scheme in order to deal with noisy quantum transmissions.
It is hard to transmit a photon, entangled over great distances. Photon detectors aren't particularly reliable.
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CONCLUSION Currently it works only over short distances,
but there are situations in which even short-distance transmission is useful. Also, with sufficient technical improvements, it might be possible in the future to implement quantum cryptography over long distances.
The devices for implementing such methods exist and the performance of demonstration systems is being continuously improved. Within the next few years, such systems could start encrypting some of the most valuable secrets of government and industry.
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THANK-YOUCREDITS
NISARG TRIVEDI