Quantum Digital Signature: Difference between revisions

All QDS protocols are divided into two phases, distribution and messaging. Distribution phase enables sender to generate private keys (kept secret with sender) and public keys (information distributed to recipients) while messaging phase enables exchange of messages using the above keys. For simlicity, most protocols use the case of three parties, one sender (Seller) and two recipients (Buyer and Verifier) exchanging one-bit classical messages signed by Quantum Digital Signatures (QDS).   

Quantum Digital Signatures provide unconditional security, not relying on any computational assumption which is its basic advantage over the classical schemes. However, over time classical unconditionally secure digital signature schemes have been realized. These classical protocols take some assumptions like trusted omnipotent (one who distributes everyone signatures) thus giving one party extra power, or authenticated message broadcast. QDS does not require any such assumption. Yet, the low key rate could render QDS impractical over classical digital signature schemes. At the same time, there exist post quantum secure Digital signature schemes based on hash-key cryptography which cannot be broken by quantum computers.  Still, if someone requires a lifetime security without the above mentioned assumptions, QDS is the answer. Areas to improve QDS could be addressing the key rate and scalability of key length with length of message.