Quantum digital signature

A Quantum Digital Signature (QDS) refers to the quantum mechanical equivalent of either a classical digital signature or, more generally, a handwritten signature on a paper document. Like a handwritten signature, a digital signature is used to protect a document, such as a digital contract, against forgery by another party or by one of the participating parties.

As e-commerce has become more important in society, the need to certify the origin of exchanged information has arisen. Modern digital signatures enhance security based on the difficulty of solving a mathematical problem, such as finding short vectors in lattices (SIS) as for ML-DSA and Falcon. Fortunately, the task of solving these problems remains infeasible when a quantum computer is available (see Shor's algorithm). Independently, new quantum digital signature schemes have been proposed to provide protection against tampering. In comparison with ML-DSA and Falcon, quantum signatures require all participants to possess and operate a quantum computer.