The quotidian life depends on complex networks of 
communication and mass collection of data and information.
From government intelligence to trivial online payments,
they all require to be secured.
However, with recent developments in quantum  computing,
the stern encryptions that secure our world become fragile;
all possible due to what a brilliant mind called:
“Real black magic calculus.” - Albert Einstein.
A classical bit is essentially an on and off switch;
Punch cards, transistors, even our smartphones, all  
function the same way.
Qubits however, exploit the superpositions of quantum 
states.
These are simply linear combinations of the computational 
basis states:
zero and one,
where the coefficients are complex numbers.
The probabilities are the squared lengths of the 
coefficients, and their sum always add up to one.
But the qubit collapses to either 0 or 1 at the moment of 
measurement.
Thus, the challenge is to isolate the system against 
anything that can collapse the wavefunction
in order to maintain the delicate superposition that allows 
performing many different simultaneous calculations.
An important example of cryptography is the Diffie-Hellman 
key exchange.
Aileen and Björn want to privately chat with each other.
They all have access to the yellow blocks.
The two each think of a secret colour that eavesdropping 
Dolly does not know.
They combine the yellow blocks with their respective secret 
blocks
and obtain lighter blocks which they then share publicly.
Aileen gets Björn’s,
Björn gets Aileen’s, 
and Dolly gets both.
Aileen and Björn combine it with their respective secret 
blocks
to produce an identical violet key that they both use to 
open the private  chat.
Dolly cannot spy over her husband Björn’s private chat as 
she does not have the secret blocks.
She will have to guess the secret blocks until she loses 
hope.
However...
Shor’s algorithm exploits quantum superposition and 
entanglement  
to perform more computations at a given point in time, 
while using fewer qubits than bits a classical algorithm   
would need.
Big O is a measure of how increasing an input N scales the 
computational time of an algorithm.
A classical computer would brute force solve an integer 
factorization problem in sub-exponential time
and the computational time explodes for higher N.
However, Shor’s algorithm for quantum computers works in 
sub-polynomial time.
Simply put, it takes a shorter time.
This makes the integer-factorization problem of Dolly
practical to solve using a quantum algorithm.
While quantum computers indeed demonstrate the potential to 
break encryption widely used in the modern day,
they are still distant in terms of development for that to 
occur.
In addition, cryptography is not just a stagnant field.
Methods of regulating “quantum supremacy” have been created 
in the form of algorithms
that inhibit these computers from breaking into your 
personal data
once they gain enough foothold to become the prominent 
computer.
Meanwhile, Dolly composes a song about auburn-haired Aileen
taking her man, Björn
to fundraise for a quantum computer to obtain back the key 
to his heart.
