Gottesman and Chuang Quantum Digital Signature: Difference between revisions

** '''Quantum One Way Functions:''' The author suggests [[quantum fingerprint states]], [[stabilizer states]] to represent classical strings in terms of quantum states. The number of qubits for the quantum state used to represent each bit in the classical string depends on which of the above methods is used. Another method where each classical bit is represented by one quantum bit, is also suggested.

** '''Key Distribution:''' The author suggests a few methods for key distribution. One of them is the assumption of a trusted third party who receives public keys from seller, checks all the keys using [[SWAP Test]] and then if test is passed by each key sent, the trusted party distributes it to the recipients. A second method eliminates the requirement of a trusted third party and instead requires Sender to send two copies of each public key to each recipient, such that, in the end each recipient has 4M keys (2M public keys for each message bit). Both buyer and verifier perform Swap test on their supposedly identical copies of public keys. Then, if passed, Buyer sends one copy of his public key to the verifier, who then performs the SWAP test between the received copy and his copy of public key.

A generalized scheme for more than three parties is given in the article. Also, for multi-bit messages, a scheme using error correcting codes has been suggested in brief.