Overview of theory Quantum Cryptography and it's applications.ppt

This is my presentation on advancements in quantum cryptography.

1. Quantum Cryptography
VISHAL VERMA
2017PH10859

2. What is Cryptography?
Cryptography is a method of protecting information and
communications through the use of codes so that only
those for whom the information is intended can read and
process it.

3. What is Cryptography?
Before the modern era, cryptography focused completely
on message confidentiality i.e. conversion of messages
from a comprehensible form into an incomprehensible
one to protect it from third parties.

4. What is Cryptography?
Before the modern era, cryptography focused completely on message confidentiality i.e.
conversion of messages from a comprehensible form into an incomprehensible one to
protect it from third parties.
The king will be assasinated tomorrow

5. What is Cryptography?
Before the modern era, cryptography focused completely on message confidentiality i.e.
conversion of messages from a comprehensible form into an incomprehensible one to
protect it from third parties.
The king will be assasinated tomorrow
————— >Shift each letter forward by 3

6. What is Cryptography?
Before the modern era, cryptography focused completely on message confidentiality i.e.
conversion of messages from a comprehensible form into an incomprehensible one to
protect it from third parties.
The king will be assasinated tomorrow
————— >Shift each letter forward by 3
Wkh nlqj zloo eh dvvdvvlqdwhg wrpruurz

7. What is Cryptography?
Before the modern era, cryptography focused completely on message confidentiality i.e.
conversion of messages from a comprehensible form into an incomprehensible one to
protect it from third parties.
Wkh nlqj zloo eh dvvdvvlqdwhg wrpruurz
Shift each letter backward by 3 <—————

8. What is Cryptography?
Before the modern era, cryptography focused completely on message confidentiality i.e.
conversion of messages from a comprehensible form into an incomprehensible one to
protect it from third parties.
Wkh nlqj zloo eh dvvdvvlqdwhg wrpruurz
Shift each letter backward by 3 <—————
The king will be assasinated tomorrow

9. What is Cryptography?
Since the development of computers post World War II,
the methods used to carry out cryptology have become
increasingly complex. Modern cryptography is heavily
based on mathematical theory and computer science
practice. It is theoretically possible to break such a
system, but it is infeasible to do so by any known practical
means.

10. Modern Cryptography
The modern field of cryptography can be divided into several areas of study

11. Modern Cryptography
The modern field of cryptography can be divided into several areas of study
Symmetric-key
cryptography
Asymmetric-key
cryptography

12. Symmetric-key cryptography
Symmetric-key cryptography refers to encryption methods in which both the
sender and receiver share the same key. Symmetric key ciphers are
implemented as either block ciphers or stream ciphers.

13. Symmetric-key cryptography
Symmetric-key cryptography refers to encryption methods in which both the
sender and receiver share the same key. Symmetric key ciphers are
implemented as either block ciphers or stream ciphers.
A block cipher is an algorithm operating on fixed-length groups of bits, called
blocks, with a transformation that is specified by a symmetric key.

14. Symmetric-key cryptography
Symmetric-key cryptography refers to encryption methods in which both the
sender and receiver share the same key. Symmetric key ciphers are
implemented as either block ciphers or stream ciphers.
In a stream cipher, each digit is encrypted one at a time with the
corresponding digit of the keystream, to give a digit of the ciphertext stream.

15. Asymmetric-key cryptography
In Asymmetric-key cryptography, there is a public, private key pair. The public
key may be freely distributed, while its paired private key is kept secret. The
generation of keys depends on cryptographic algorithms based on
mathematical problems to produce one-way functions.

16. Asymmetric-key cryptography
Customer ——————> Restaurant Manager
Message = Bad Chef
Public Key of the restaurant = 3, 10

17. Asymmetric-key cryptography
Customer ——————> Restaurant Manager
Message = Bad Chef
Public Key of the restaurant = 3, 10
B A D C H E F
2 1 4 3 8 5 6

18. Asymmetric-key cryptography
Customer ——————> Restaurant Manager
Message = Bad Chef
Public Key of the restaurant = 3, 10
B A D C H E F
2 1 4 3 8 5 6
8 1 64 27 512 125 216 Cube
8 1 4 7 2 5 6 Remainder after division from 10

19. Asymmetric-key cryptography
Restaurant Manager
Encrypted Message = 8 1 4 7 2 5 6
Private Key of the restaurant = 3
8 1 4 7 2 5 6

20. Asymmetric-key cryptography
Restaurant Manager
Encrypted Message = 8 1 4 7 2 5 6
Private Key of the restaurant = 3
8 1 4 7 2 5 6
512 1 64 343 8 125 216
2 1 4 3 8 5 6

21. Asymmetric-key cryptography
Restaurant Manager
Encrypted Message = 8 1 4 7 2 5 6
Private Key of the restaurant = 3
2 1 4 3 8 5 6
B A D C H E F Decrypted Message

22. Asymmetric-key cryptography
Current industry standard is to use 2048 bits public key.
The first number of the public key is a constant.
The important number in the public key is the second number, the one we used
as divisor. It is always taken to be a product of two large prime numbers. In our
case, 10 = 5 x 2
The private key can easily be calculated if one knows the said two prime numbers.
It is not possible to find the numbers using current computation power for a 2048
bit number.

23. Going Quantum
In 1994, American mathematician Peter Shor developed a quantum
computer algorithm for integer factorization. It is able to factorize an integer
N into its prime factors polynomial time (the time taken is polynomial in Log
N). It has a time complexity of O((log N)
2
(log log N)(log log logN))
demonstrating that the integer-factorization problem can be efficiently
solved on a quantum computer.

24. Going Quantum
In 1994, American mathematician Peter Shor developed a quantum
computer algorithm for integer factorization. It is able to factorize an integer
N into its prime factors polynomial time (the time taken is polynomial in Log
N). It has a time complexity of O((log N)
2
(log log N)(log log logN))
demonstrating that the integer-factorization problem of large numbers can
be efficiently solved on a quantum computer.
Fortunately, no such quantum computer has been developed
successfully so far.

25. Going Quantum
In 2001, Shor's algorithm was demonstrated by a group at IBM, who factored
15 into 3 times 5, using a quantum computer with 7 qubits. In 2012, the
factorization of 21 was achieved, setting the record for the largest integer
factored with Shor's algorithm.

26. Going Quantum
In 2001, Shor's algorithm was demonstrated by a group at IBM, who factored
15 into 3 times 5, using a quantum computer with 7 qubits. In 2012, the factorization of 21
was achieved, setting the record for the largest integer factored with Shor's algorithm.
There are many other algorithms known as Quantum optimization
algorithms. They are also used to factorize large integers into their prime
factors. They have shown promising results but still need a lot of research to
have a real-life application.

27. Quantum Cryptography
Quantum cryptography is the science of exploiting quantum mechanical
properties to perform cryptographic tasks such as quantum key distribution
which offers an information-theoretically secure solution to the classical key
management problems.
One of the most important properties used in Quantum Cryptography is that
it is impossible to copy data encoded in a quantum state. This is known as No-
Cloning theorem.

28. No-Cloning Theorem
In physics, the no-cloning theorem states that it is impossible to create an
identical copy of an arbitrary unknown quantum state.
Intuitively, it is easily understood if one remembers the heisenberg
uncertainty and superposition principle. In order to clone/copy a quantum
state, one needs a method of copying the exact and complete information of
the original state which is impossible.

29. No-Cloning Theorem
In physics, the no-cloning theorem states that it is impossible to create an
identical copy of an arbitrary unknown quantum state.

30. Quantum Key Distribution
Just like classical Cryptography, there are many protocols/types of Quantum
Cryptography. One of the most popular is Quantum Key Distribution.
Quantum key distribution (QKD) is a secure communication method which
implements a cryptographic protocol involving components of quantum
mechanics. It enables two parties to produce a shared random secret key
known only to them, which can then be used to encrypt and decrypt
messages.

31. Quantum Key Distribution
An important and unique property of quantum key distribution is the ability of
the two communicating users to detect the presence of any third party trying
to gain knowledge of the key. This results from a fundamental aspect of
quantum mechanics: the process of measuring a quantum system in general
disturbs the system.
The security of encryption that uses quantum key distribution relies on the
foundations of quantum mechanics, in contrast to traditional public key
cryptography, which relies on the computational difficulty of certain
mathematical functions.

32. Quantum Key Distribution
Let’s explain it using an example. Bob and Alice want to generate a shared
key using Quantum Key distribution Method.
Photon polarization is used as the basis for measurements. The usual
polarization state pairs used are either the rectilinear basis of vertical (0°) and
horizontal (90°), the diagonal basis of 45° and 135° or the circular basis of
left- and right-handedness.

33. Quantum Key Distribution
Bob and Alice want to generate a shared key using Quantum Key distribution Method.

34. Conclusion
Quantum Cryptography is growing field. There are new discoveries made
each day. Quantum Key distribution is one of the many applications of
Quantum Cryptography. Others include Mistrustful Quantum Cryptography,
Quantum coin flipping, Quantum commitment, etc.
Quantum Computers are coming and we will have to start
using Quantum Cryptography instead of Classical
Cryptography techniques.

35. References
https://en.wikipedia.org/wiki/Quantum_cryptography
https://en.wikipedia.org/wiki/Quantum_key_distribution
https://en.wikipedia.org/wiki/Cryptography
https://en.wikipedia.org/wiki/Symmetric-key_algorithm
https://en.wikipedia.org/wiki/Public-key_cryptography
https://www.youtube.com/watch?v=owPC60Ue0BE
https://www.youtube.com/watch?v=6H_9l9N3IXU
https://www.youtube.com/watch?v=M7kEpw1tn50
http://www-inst.eecs.berkeley.edu/~cs191/fa05/lectures/lecture6_fa05.pdf

36. Thank You