• Quantum cryptography offers information-theoretic security
  • Quantum cryptography’s security comes from the fact that each qubit is carried by a single photon

Utilizing the concepts of quantum physics, quantum cryptography provides enhanced security. No one will be able to access the data transported and encrypted using this method due to the extremely high level of security that arises from the integration of quantum physics into encryption.

Quantum cryptography transmits and transfers data using discrete light elements like photons. To transmit this data, fibre optic wires are employed. Since photons act as a substitute for binary bits, the security is dependent on the application of quantum physics. Because photons and other light particles can exist in multiple places at once, their utilization is effective. No quantum attribute may be observed unaltered and the particles cannot be replicated. These characteristics allow quantum cryptography to provide the highest level of security. 

Quantum cryptography has advantages.

Quantum cryptography offers information-theoretic security, which means that the system’s security is based on fundamental physical principles rather than computational assumptions. It provides a level of security that can be proven, making it resistant to attacks from quantum computers that could compromise more conventional cryptographic algorithms.

Quantum Key Distribution: Quantum key distribution (QKD) is the main use of quantum cryptography. With QKD, two parties can exchange cryptographic keys with complete security. Due to the intrinsic characteristics of quantum physics, any eavesdropping efforts during key distribution can be identified, guaranteeing that the shared key is kept secure.

Eavesdropping Attempt Detection Quantum cryptography offers the capacity to identify any eavesdropping or data-tampering attempts. Quantum states, such as entangled photons, are used in the QKD process, and measurement results are observed. These quantum states would be disturbed by any unauthorized attempt to intercept or measure them, alerting the communication parties about the presence of an eavesdropper.

Long-Term Security: Since quantum cryptography is based on physical rules rather than the computational complexity of mathematical algorithms, it provides long-term security. The cryptographic keys transferred using QKD can be regarded as secure for as long as the system’s physical implementation is secure.

Quantum cryptography’s drawbacks

Practical Implementation problems: Quantum cryptography implementation presents considerable technological problems in real-world applications. The hardware needed for distributing quantum keys is intricate and delicate, frequently requiring specialized tools and carefully controlled settings. Quantum encryption systems still have limitations in terms of their usability and scalability, and mainstream acceptance is still very difficult to achieve.

Limited Line-of-Sight and Range Requirement: Due to the characteristics of the quantum states utilized for key distribution, quantum cryptography systems often require a direct line-of-sight between the communicating parties. This condition restricts the range of secure communication and makes quantum cryptography deployment challenging in some network topologies or situations with physical barriers.

Limitations on Key Distribution: While quantum cryptography makes it possible to distribute keys securely, it does not immediately address other security-related communication issues like data encryption and authentication. Quantum key distribution needs to be combined with other cryptographic protocols or algorithms to provide complete security in real-world situations.

Vulnerability to Side-Channel Attacks: Despite providing protection against attacks based on computational capacity, quantum cryptography may still be susceptible to side-channel assaults. Side-channel attacks make use of flaws in a cryptographic system’s implementation or structural elements, including monitoring the devices’ electrical or electromagnetic emissions. In order to lessen these vulnerabilities, appropriate countermeasures must be put in place

Cost and Complexity:Due to the requirement of specialized hardware and infrastructure, quantum cryptography implementations can be prohibitively expensive. The high expenses involved with quantum cryptography are further exacerbated by the complexity of the technology and the knowledge required for its implementation.


The security of quantum cryptography derives from the fact that each qubit is carried by a single photon. As soon as a photon is read, it is transformed. A public channel is used to send encrypted messages while the quantum channel is used to exchange keys. To strengthen the system, sender and recipient can communicate findings and how they used their chosen basis (rectilinear or diagonal) through a public channel.

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