In this lesson,
we will learn about Post-Quantum Cryptography.
Post-quantum cryptography
refers to cryptographic algorithms,
specifically designed to withstand the advanced threats
posed by quantum computers.
Quantum computers with their immense computational power
are expected to break many of the encryption methods
that are currently relied on for security.
In this Post-Quantum cryptography section of the course,
we will compare post-quantum cryptography
to Diffie-Hellman and Elliptic Curve Cryptography.
Let's learn more
about the mechanics of quantum cryptography
and post-quantum versus Diffie-Hellman
and Elliptic Curve Cryptography.
First, let's explore how quantum computing
and quantum cryptography work.
Quantum computing combines principles
from physics, mathematics, and quantum mechanics
to harness the unique properties of quantum states,
such as a superposition
and entanglement to perform computations.
A quantum represents the smallest unit
of any physical property,
such as particles at the atomic or subatomic level.
Traditional computing relies on bits
that can either be a zero or a one.
While quantum computing
uses qubits or quantum bits,
which can exist in multiple states at once
due to superposition.
Superposition allows a qubit
to be in a combination of states
like both zero and one simultaneously,
vastly increasing computational power.
Entanglement is a phenomenon
where two or more qubits become interconnected,
meaning the state of one qubit
instantly influences the state of others
regardless of distance.
This ability to hold, coordinate,
and process multiple states simultaneously
allows quantum computers
to perform complex calculations
much faster than traditional computers,
making them particularly powerful
for solving a cryptographic problems.
For example, a 1000-qubit quantum computer
would vastly outperform
today's most powerful supercomputers.
Today's cryptography relies
on complex mathematical problems
to keep data secure,
but quantum computers can quickly break
traditional encryption methods due to their ability
to process multiple possibilities all at once.
For example, the computational strength
of quantum algorithms,
such as Shor's algorithm
poses a threat to current cryptographic standards
because it can effectively solve
the mathematical problems
that underpin encryption algorithms
like Diffie-Hellman and Elliptic Curve Cryptography.
This means that once quantum computers
become fully operational,
they could render current encryption techniques obsolete,
making it essential
to develop quantum resistant cryptographic methods
to protect our data.
As of 2024, quantum computers
are operating with qubit counts
that vary widely depending upon the technology
and the company developing them.
Leading quantum computing companies like IBM and Google
have made significant strides
in increasing qubit numbers.
IBM's latest quantum processor
known as the Osprey boasts 433 qubits,
representing one of the highest publicly announced
qubit counts in universal quantum computing.
Google's Sycamore processor,
which previously demonstrated
quantum supremacy, operates with 53 qubits,
though the focus has since shifted
towards scaling up and reducing errors.
Overall, most current universal quantum computers
are operating in the range of 500 to 50 qubits,
with ongoing research aiming to increase qubit counts
and improve their stability
and error correction capabilities.
And while 50 to 500 qubits
is a lot of processing power,
most current estimates
predict that a quantum computer
will need somewhere in the neighborhood
of 3000 or more qubits
to be a threat to today's cryptographic algorithms.
Now that we understand the state of quantum computing,
let's learn about two primary strategies
for safeguarding data against quantum computing.
These are increasing key sizes
and developing new algorithms
that are quantum resistant.
Increasing the key size adds more permutations
that need to be brute forced to crack the encryption,
making symmetric encryption algorithms
like the Advanced Encryption Standard
or AES more resilient.
For example, moving from AES-128 to AES256
doubles the key length,
but it exponentially increases the number of combinations
a quantum computer would need to attempt
significantly extending the time required
to crack the encryption.
The second strategy for safeguarding data
involves implementing quantum-resistant algorithms,
which researchers are actively developing.
Examples include a lattice-based cryptography
and supersingular isogeny exchanges.
These new algorithms are designed
to withstand a attacks from quantum computers.
Also, the National Institute of Standards and Technology,
or NIST, is currently holding a competition
to select a quantum resistant cryptographic standard
expected to be finalized in the coming years
as it is anticipated that functional quantum computers
could emerge by the year 2030.
We will talk more about post-quantum cryptography
in the next section of this lesson.
Wow, that's intense,
but before we can discuss post-quantum security,
we need to understand the mechanics
and current state of quantum cryptography.
Now, let's learn more about post-quantum cryptography
versus Diffie-Hellman and Elliptic Curve Cryptography.
Post-Quantum Cryptography, or PQC,
is an emerging field
that aims to develop cryptographic algorithms
that can resist the advanced capabilities
of quantum computers.
As we have discussed,
quantum computers are fundamentally different
from traditional computers
because they use qubits,
which can exist in multiple states simultaneously
due to quantum phenomena
like superposition and entanglement.
This allows quantum computers
to perform many calculations at once,
making them capable of solving complex problems
much faster than conventional computers.
This power poses a significant threat
to existing cryptographic methods,
including Diffie-Hellman and Elliptic Curve Cryptography.
Diffie-Hellman and Elliptic Curve Cryptography
are widely used today
because they provide robust security
through complex mathematical operations.
Diffie-Hellman facilitates secure key exchanges,
allowing two parties to establish a shared secret
over an insecure channel.
Elliptic Curve Cryptography, on the other hand,
uses the properties of elliptic curves
to create secure and efficient keys,
making it suitable
for resource-constrained environments
like mobile devices.
However, both methods are vulnerable to quantum attacks
because the underlying mathematical problems
can be solved quickly by quantum computers.
This vulnerability is driving the development
of Post-Quantum Cryptography,
which aims to create encryption methods
that can withstand quantum attacks.
PQC or post-quantum cryptography algorithms
are built on mathematical problems
that are believed to be difficult
for quantum computers to solve,
even with their advanced processing capabilities.
These new algorithms are intended to replace
or complement existing methods
like Diffie-Hellman and Elliptic Curve Cryptography,
ensuring data remains secure in the future
where quantum computing is prevalent.
A critical component of Post-Quantum Cryptography
is lattice-based cryptography,
lattice-based cryptography,
is one of the most promising approaches
to quantum resistant encryption.
Lattice-based cryptography
uses complex, high-dimensional mathematical structures
that are resistant
to both classical and quantum attacks.
Unlike Diffie-Hellman and Elliptic Curve Cryptography,
which rely on discreet logarithms,
lattice-based methods like Learning With Errors
and Ring Learning With Errors
offer a strong security against quantum threats.
These algorithms are being designed
to protect key exchanges, digital signatures,
and data encryption in the quantum era.
So remember, Post-Quantum Cryptography, or PQC,
is an emerging field
focused on creating cryptographic algorithms
that can resist the powerful capabilities
of quantum computers.
Quantum computers, unlike traditional computers,
use qubits that can exist in multiple states at once,
allowing them to perform many calculations simultaneously
and solve complex problems much faster.
This poses a significant threat
to existing encryption methods
like Diffie-Hellman and Elliptic Curve Cryptography,
which rely on mathematical problems
that quantum computers can easily solve.
Post-Quantum Cryptography
aims to develop new cryptographic algorithms
that are resistant to quantum attacks,
ensuring data remains secure
even as quantum technology advances.
As quantum computing evolves,
the adoption of Post-Quantum Cryptography
will be important to protect our data
against these future threats.