A quantum algorithm is a set of instructions designed to be executed on a quantum computer, which uses the principles of quantum mechanics. Unlike classical algorithms that operate on bits (0s and 1s), quantum algorithms work with quantum bits or qubits, which can represent both 0 and 1 simultaneously due to a property called superposition. This allows quantum algorithms to process a vast amount of information more efficiently than classical algorithms for certain tasks. One of the most famous quantum algorithms is Shor's algorithm, developed by mathematician Peter Shor. It can factor large numbers exponentially faster than the best-known classical algorithms, posing a potential threat to current encryption methods. Another notable example is Grover's algorithm, which provides a quadratic speedup for unstructured search problems. These advancements highlight the potential of quantum computing to revolutionize fields such as cryptography and optimization.