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Classical internet vs. quantum internet: How do they differ?

The quantum internet is a hypothetical secure network made of qubits. It differs from the classical internet with its use of quantum principles for enhanced security and computing.

The quantum internet is a hypothetical high-speed internet that provides ultrasecure connectivity to quantum devices across the globe. In the future, the quantum internet will be a collective of network mega clusters that consist of small quantum infrastructures separated by long distances or international borders.

While quantum computers exist in the physical world, the concept of the quantum internet is currently theoretical. Existing quantum networks currently don't expand beyond research rooms, but they relate to quantum computing. For example, the quantum internet is based on quantum mechanical phenomena, such as superposition and entanglement, and implements quantum cryptographic protocols for safeguarding communication.

Research teams are conducting trials to establish entanglement over long distances, and scientists continue to theorize how they expect the quantum internet to operate once developed. When fully realized, the quantum internet will integrate with the classical internet to fix complex problems and enable secure communication and high-speed computing.

Classical internet vs. quantum internet

The quantum internet won't replace the classical internet. Instead, it will add better functionalities to connect devices in homes, commercial businesses and enterprises. Current quantum computers access the classical internet to perform certain tasks. All quantum devices will eventually need to support the quantum internet through quantum networking protocols.

Units of data

The classical internet enables devices to transmit, receive, compute and store information represented in the form of bits. A bit is the smallest unit in computing that indicates a device's logical state, such as on and off, represented as 0 or 1, respectively. A group of bits can represent a character in a text, a pixel in an image or a frame in a video. In other words, groups of bits represent every piece of information on the internet.

The quantum internet enables interconnected quantum networks to exchange information, known as qubits, encoded in two quantum states. Similar to how a bit represents either 0 or 1, a qubit represents two quantum states.

A quantum state depicts either the polarization of a photon or the spin of an electron. These properties let qubits encode information in a quantum network. They propel qubits into a state of superposition, in which a qubit is in both states simultaneously and any change to the qubit affects both states.

In the quantum internet, logical operations, such as error correction or encryption, can change individual qubits without affecting other qubits in the data packet. This differs from the deterministic processing used in the classical internet, where transmission changes based on the overall information in a data packet.

Modes of operation

The classical internet sends data from the source to destinations at high speeds. Each source and destination has a unique IP address. Network protocols encapsulate information in packets and send data over channels from the transmitter to the receiver. The classical internet relies on the TCP/IP protocol to ensure reliable data delivery, IP addressing, routing, security and other important network requirements.

Because the quantum internet is still hypothetical and in the early stages of small-scale development, no well-defined networking protocol suite like TCP/IP exists for it yet. However, researchers have developed various quantum networking protocols over the years to make current quantum communication possible. Quantum networking protocols rely on quantum mechanical principles to exchange qubits within a network.

Coverage areas

The classical internet is a global interconnected network made of smaller networks around the world. Billions of networks make up the internet, and billions of users access it every day to browse the web, consume information and communicate with others.

The coverage of the quantum internet is complex to measure because it only exists in hypothetical scenarios. Quantum researchers generate entangled states over large distances to test the expansion of quantum networks. Studies have shown the quantum network range for fiber-based communication is around 62 miles. Scientists implement quantum repeaters to capture weak signals for retransmission to increase the range of quantum communication.

Quantum vs. classical internet security

In the classical internet, network security protocols enable the formation of secure channels for an uninterrupted connection. Examples of network security protocols include the following:

  • IPsec.
  • VPN tunneling protocols.
  • Secure Socket Layer (SSL).
  • Secure Shell (SSH).
  • Tunneled Layer Security (TLS).
  • Wi-Fi Protected Access (WPA).

In the quantum internet, however, the development of cryptographic protocols relies on quantum key distribution (QKD). QKD shares a secret irreplicable key between the devices connected to the quantum internet. Hackers can't accurately determine the state of an entangled qubit because any measurement collapses the wave function. The quantum internet also implements quantum cryptographic protocols to safeguard communication.


The classical internet generally operates reliably, but the reliability rate of data packet transfer isn't always guaranteed. Networks often experience packet loss due to congestion and hardware failure, among other factors. Packet loss prevents data from transmitting on the internet and sometimes creates latency.

The quantum internet might also experience qubit loss, a problem similar to packet loss. Qubit loss, also known as quantum decoherence, is an issue that frequently occurs when all components in a quantum environment interact with a system, which leads to photon loss. Because quantum networking is still in the early stages, scientists don't quite yet know how to prevent or fix decoherence, but researchers continue to study its causes.

Quantum vs. classical internet speeds

Classical internet speeds range from Mbps to Gbps. Mbps speeds are suitable for basic internet activities, such as web browsing, sending emails and streaming. Gbps speeds support more bandwidth-intensive use cases, such as file downloads, video conferences and gaming.

Early theories predicted quantum communication are faster than the speed of light, but current research suggests it isn't. Researchers theorized quantum communication goes against the causality principle, which states that every cause has an effect. Quantum communication defies this principle because entanglement -- the property that links qubits together to enable communication between them -- can occur regardless of how far qubits are from each other.

Quantum entanglement necessitates that two-qubit states are directly dependent on each other. Theoretically, qubits could be a billion miles from each other, but they can communicate with each other instantaneously. Because quantum entanglement states it's impossible to measure both the position and momentum of an entangled particle, it's unlikely the speed of the quantum internet will move at the speed of light.

Quantum vs. classical internet comparison

The table below summarizes the differences between quantum internet and classical internet.

Characteristic Classical internet Quantum internet
Unit of data Bit Qubit
Mode of operation TCP/IP protocol suite Principles of quantum mechanics
Coverage Global Smaller, with some quantum computing networks
Security protocols IPsec, VPN, SSL, SSH, TLS, WPA QKD, quantum secure direct communication, quantum cryptographic protocols
Reliability High, but with packet loss Low, with frequent need for error correction codes
Speed Mbps to Gbps

Theoretically high

Implementation status 5.4 billion global users Hypothetical

How the quantum and classical internet work together

Researchers anticipate the quantum internet and classical internet will work together to fix complex problems. Some ways in which the quantum internet and classical internet could work together include the creation of quantum hybrid networks, supercomputing or superconductor bits.

Quantum hybrid networks

A quantum hybrid network implements elements of both the classical internet and quantum networks in a single network. An integration could extend security through QKD. The no-cloning theorem prevents the generation of duplicate copies of any quantum state, but redundancy is necessary in enterprise environments. In addition, quantum networks are prone to errors. Network administrators can deploy error correction devices in quantum networks to eliminate errors.

Quantum internet could surpass supercomputing

The terms quantum networking and supercomputing seem interrelated, but in practice, supercomputers are a classical internet use case. A supercomputer is a general-purpose machine that operates on bits to perform lengthy, complex computations and handle large volumes of data. Even in the initial stages, the quantum internet can help quantum computers surpass the decade-long legacy of supercomputers in real time.

Superconductor bits

Superconducting quantum computing describes the integration of superconductors and quantum networks. In other words, superconducting bits are realized in superconductive circuits. Superconductors replace semiconductors hardware. Experts predict the quantum internet will run on superconductor-based devices in the future to enable quantum cloud computing.

Quantum internet: Web x.0

The classical internet first developed as Web 1.0 in the '90s and gave users static control over the internet. The second stage, Web 2.0, was the dynamic social media revolution that focused on connecting users. The latest iteration, Web 3.0, focuses on decentralization and ownership.

Experts visualize the concept of Web 4.0 as an AI integration of physical and virtual worlds. The quantum internet could be a step ahead of the advanced stages of Web 4.0 or any other future iteration of the web. Quantum internet could lead to a hacker-less, fast and irreplicable internet.

Venus Kohli is an electronics and telecommunications engineer, having completed her engineering degree from Bharati Vidyapeeth College of Engineering at Mumbai University in 2019. Kohli works as a technical writer for electronics, electrical, networking and various other technological categories.

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