1 Ojectives


Create encryption methods that cannot be broken by algorithms, or calculations, that run on future quantum computers

Today's encryption methods will not necessarily remain secure if & when quantum computers become a reality

huhhh, really?


2 Existing Phenomenon



1977 RSA Algorithm

The encryption system relies on the fact that it is

Prohibitively time consuming
Computationally intensive

-- to factor the large integer in the public key
-- to determine the two prime numbers that make up the private key


1994 Shor's Algorithm


Theoretically, Peter Shor states:
"quantum computers could factor incredibly large numbers efficiently"


1994 DSA -- Digital Signature Algorithm


It works in the framework of public-key cryptosystems and is based on the algebraic properties of modular exponentiation, together with the discrete alogarithm problem


1999 ECDSA -- Elliptic Curve Digital Signature Algorithm


ECDSA offers a variant of the DSA which uses elliptic-curve cryptography.


In cryptography, the secrecy, and uniqueness of the random signature value κ are critical.
It is so critical that violating any one of those three requirements can reveal the entire private key to an attacker


Malicious implementations of DSA and ECDSA can be created where κ is chosen in order to subliminally leak information via signatures



3 Quantum Cryptography

1994 Quantum Key Distribution (QKD)

The 1st instance of QKD Application was demonstrated through a protocol called BB84, developed by Charles Bennett & Gilles Brassard

Objectives


To securely exchange cryptographic keys between two parties

The key idea is that any eavesdropping attempt on the quantum communication would disturb the system, hence alerting the legitimate parties to the presence of the eavesdropper

In theory, quantum cryptography is unhackable
because eavesdropping would always be detected

Its practical uses are limited


Experimental Demonstrations


1990s

2004 "QKD over a real optical fiber network" -- 🇨🇳 claimed

2007 "1st Intercontinental QKD over China & Austria" -- 🇨🇳 claimed


QKD continues to evolve, with numerous implementations today, especially in secure communication systems & satellite-based quantum communication.

Scientists have demonstrated that QKD works

Currently, it is not widely used due to significant technological limitations


Methodologies


To send a quantum key:
a single-photon laser beams a signal
one photon at a time, via a fiber optic cable


This method is slower than current telecommunication technologies, as it requires a dedicated fiber optic cable between the two parties.


Metaphorically,

"If you build a house, it's only going to be as strong as the weakest pillar"

"To have a truly usable system, you may need to combine quantum cryptography with elements that are not quantum, and those other elements could be vulnerable to attacks that theorists have not envisioned."
Prof Thomas Vidick, Caltech





Quantum Computers


Does Quantum Computers even EXIST


The Paradox


2035 -- 2040 Near Term
2040 -- 2060 Long Term



A general-purpose quantum computer, capable of solving a broad range of real-world problems, could emerge. However, this depends heavily on solving the issues with scalability and error correction.

A full, practical quantum computers are still likely a couple of decades away, the research is progressing & breakthroughs can happen decades later.