Overview: On quantum cryptography
Quantum cryptography is the next chapter in cryptography currently in use. This part of encryption originates from physical principles, involving physical mechanisms and computational power. This computational power and quantum mechanism were used to create two powerful security systems, quantum key distribution and quantum secure cryptography.
We'll cover quantum cryptography and cryptography in detail in this guide, and we'll also use this article to learn how quantum cryptography works and what its applications are in our world.
Explaining quantum cryptography
Quantum cryptography applies the principles of quantum mechanics to cryptography and cryptography. When quantum mechanisms are integrated into encryption, the resulting security is so strict that no one can access the data shared and protected by the system.
Even if hackers had access to the quantum computer and the entire suite, they wouldn't be able to break the encryption offered here. This is because quantum cryptography uses quantum polymorphism and the “invariant theory” to protect information.
There is no doubt that quantum cryptography is better, more reliable, and more credible than the traditional cryptographic measures we use to date. The Advanced Encryption Standard (AES) makes the data almost impossible to crack, but it's also unbreakable.
Appearance of Alice and Bob (example)
To describe the working principles behind quantum cryptography, here's a case example that will help make things more clear. Let's say Alice wants to send Bob a message. As she writes information and polarizes each photon through a polarizer to change its direction to a specific type. This can be horizontal, vertical, or diagonal.
The encryption key here is a change in the direction of the photons. Once received, Bob guesses the polarizer and decodes the information. Here Bob will guess the photon case and match it to the case Alice generated.
In this example, let's say another person is trying to access the message. In the crypto world, this person is commonly referred to as Eve. Eve uses her own polarizer to get information. If Eve used a polarizer to decode, Bob and Alice would say there's a difference here because we can't change the photon's properties without moving or altering it.
With this back-end principle, quantum cryptography was developed to be used as a protective measure to protect data, transactions, communications, and information.
Principles of quantum cryptography
Quantum cryptography uses individual light particles such as photons for data transmission. This data is transmitted over fiber. Photons represent binary bits, so safety depends on the execution of quantum mechanics.
Using photons or light particles is effective because these particles can exist in two or more places at the same time. Furthermore, if quantum properties are not changed first, they cannot be changed or observed, and particles cannot be copied.
With these aspects, quantum cryptography can provide the highest form of security. Some might say that keys shared through quantum cryptography are unbreakable because the principle of photons is applied here.
However, we've seen some possibilities for circumventing the security that this system provides. However, there is currently no evidence or proof. Even with quantum computing capabilities, cracking a quantum key is not an easy task.
Let's learn some details about photons. In quantum cryptography, every photon passing through a cryptographic system represents a binary code. It can be 0 or 1.
The key represents a string of 1s and 0s, creating a coherent message that only the two entities involved can encrypt and decrypt. Quantum computational cryptography works in a similar way to AES, but due to the nature of photons, we can see significant changes in security.
The binary bits converted from the photon provide the photon with a unique spin. It can be vertical, horizontal, right diagonal, or left diagonal. This provides a unique code or cryptographic attribute for the key.
Heisenberg's uncertainty principle
This principle means we can't measure or calculate the position and momentum of an object. This principle does not apply to the macroworld, where small changes in the macroworld are often overlooked.
But in the quantum world, even the smallest changes can have a huge impact. Therefore, the Heisenberg uncertainty principle plays an important role in quantum computation and cryptography.
Why is there a demand for quantum cryptography?
Have you ever heard the phrase “necessity is the mother of invention”? The origin of quantum cryptography and cryptography has a similar story. With the advent of quantum computing, existing cryptographic standards may become weak.
Using the Shor algorithm in quantum computing, computers can break asymmetric cryptography. An ordinary computer cannot find the key prime number in the RSA encryption standard for decrypting the key. But quantum computers can find prime numbers. As a result, it can break the key.
The AES-64 and AES-128 bits of AES became vulnerable to “violent” attacks by quantum computers. Although they still haven't been hacked, violent attacks have lowered the bar on their safety net.
This somewhat reduces the AES-128 bit to the AES-64 bit and the AES-256 bit to the AES-128 bit. Of course the AES-128 bit standard still protects information, but we can say that it's only a matter of time before quantum computers crack passwords.
Quantum Secure Cryptography and Quantum Key Distribution (QKD)
Quantum cryptography and cryptography gave rise to two concepts:
Quantum-secure cryptography
Quantum-secure cryptography determines methods, efforts, and algorithms for key resistance attacks. It basically determines measures to protect any data from hacking classic computers or quantum computers used in everyday life.
The focus here is on quantum computers because they have higher computational power and possibilities.
Quantum-secure cryptography is also known as post-quantum cryptography. Currently, NIST is working to solicit, evaluate, and standardize anti-quantum public key cryptography algorithms. Once they are approved and standardized, quantum cryptographic keys can be used by the public.
Existing cryptographic standards such as AES, ECC, and RSA all use mathematical equations to generate ciphertext. But with quantum cryptography, we can use physical and mathematical equations to generate ciphertext.
Quantum key distribution
Quantum key distribution (QKD) involves sending data in the form of photons over an optical link. Its purpose is to ensure data protection and data security, and QKD, a system created using quantum cryptography, can easily provide this.
The higher form of security that QKD provides stems from the fact that it can easily detect any kind of intrusion. This will alert the relevant party or entity to discard the key used for data transmission.
QKD is one of the most commonly used communication channels. We can choose from a number of protocols to implement QKD. But it requires a quantum channel and a proven classical channel.
A quantum channel transmits a state of light in the form of photons, while a classical channel is a sender and receiver channel.
Is quantum secure cryptography “unbreakable”?
In every discussion about quantum cryptography and cryptography, the laws of quantum mechanics pop up. The activity of sending cryptographic keys back and forth between two entities in the form of photons is theoretically untraceable.
The fiber-optic line is a critical component of this system. We've discussed all fiber optic lines and how they make transmission secure. However, another transmission method is used here, which is the use of a satellite key exchange.
In satellite-based methods, the entanglement principle comes into play.
Here's a bit off topic. In entanglement, when two particles get entangled to a certain extent, they reach the same state. Once this is achieved, one of the particles will be sent to the others. When the particle is received at the other end, it is guaranteed to be in a state similar to its twin particle.
It's an uncertain fact that if one of the particles changes, the other will change to match. This is because we are not using entanglement for communication purposes.
Therefore, we can't communicate using this property, but we can use it to share an encryption key, and then use the encryption key to protect communication over traditional channels.
Based on the equipment, technology, and system to which this system is applied, we can say that quantum cryptography is currently unbreakable. Even with the quantum computing systems we can use today, hacking communication, data, and transmission is virtually impossible.
Advantages and Disadvantages of Quantum Cryptography
While quantum cryptography and cryptography have their advantages, they also have some drawbacks.
Advantages of quantum cryptography
Communication is secure: Using quantum cryptography, the security level of communication is higher than traditional encryption standards. Since it is based on the laws of quantum physics, communication is more secure.
Multiple safety methods: Quantum computing and physics provide the required security through different methods. We've already discussed entanglement and polarizers in the section above. However, in the future, more methods can be derived through more research and development.
Detection: Using quantum secure cryptography, we can detect whether an entity other than two entities authorized to access data is attempting to invade.
Limitations of quantum cryptography
Even a technology as good as quantum cryptography has its limitations.
Limited by scope: Due to the limited application range of entanglement systems, we can only rely on optical cables to achieve quantum encryption. These wires can only be laid over a limited distance. The maximum length is 500 km.
Polarization changes: Photons are prone to polarization changes, even during transmission. This may result in a higher error rate.
Expensive equipment: Not just fiber optic cables, all the equipment needed to set up and install a quantum cryptographic system is very expensive.
conclusions
We've evolved from mathematical equations that help us secure our data and online communications to the physics we use for the same purpose. As quantum computing and cryptography allow businesses, governments, and organizations to further protect their data, it will be nearly impossible for hackers to break into systems.
Despite their limitations, quantum cryptography and cryptography are highly secure and useful.
For some time to come, we can see large-scale implementation of cryptographic technology.
