A quantum-resistant algorithm, also known as a post-quantum algorithm or quantum-safe algorithm, is a cryptographic algorithm designed to be secure against attacks by quantum computers. It is specifically developed to withstand the threat posed by powerful quantum computers, which have the potential to break many commonly used classical cryptographic algorithms.
The goal of a quantum-resistant algorithm is to provide a level of security that remains intact even in the presence of a quantum computer capable of running quantum algorithms, such as Shor's algorithm, which can efficiently factor large numbers and break certain cryptographic schemes. Quantum-resistant algorithms are designed to resist attacks by taking advantage of mathematical problems that are believed to be hard for both classical and quantum computers.
While classical cryptographic algorithms rely on mathematical problems that are difficult to solve for classical computers, they can be efficiently solved by quantum computers due to their ability to perform certain computations much faster. In contrast, quantum-resistant algorithms are designed based on mathematical problems that are believed to be resistant to attacks by both classical and quantum computers. Examples of such mathematical problems include lattice-based cryptography, code-based cryptography, multivariate polynomial cryptography, and hash-based cryptography, among others.
The development and standardization of quantum-resistant algorithms are essential to ensure that critical infrastructure, communication channels, and sensitive data remain secure in the era of quantum computing. Cryptographers and researchers worldwide are actively investigating and developing these algorithms to provide long-term security against the cryptographic threats posed by powerful quantum computers.