Digital Signatures (QDS) allow the exchange of classical messages from sender to multiple recipients, with a guarantee that the signature has come from a genuine sender. Additionally, it comes with the properties of transferability, non-repudiation and unforgeability. In contrast, classical digital signatures rely on authentication (taken as an assumption for some QDS protocols) i.e. the message has come from the claimed party; integrity i.e. the message has not been altered (if authentication is confirmed, this property is unforgeability) and non-repudiation (same as QDS). These properties distinguish quantum digital signatures from quantum authentication. Quantum messages can be authenticated but not signed [1], [2]. Note that QDS schemes sign classical messages and not quantum messages.
The protocols that implement this functionality are:
No content has been added to this section, yet!
No content has been added to this section, yet!
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 simplicity, 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).
Unlike classical digital signature schemes which generalize a two party model, QDS protocols always study a three party model as transferability is not inherent and has to be proved in the quantum case. Given this situation, usually, the third party acts as the judge (a verififer) who would gain nothing out of cheating, and hence, cheating strategy is only studied for seller (repudiation) and buyer (forgery). 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 extra some assumptions like trusted omnipotent (one who distributes everyone signatures) 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. Following are a few articles useful for those interested in a more detailed overview of QDS.
Some review papers:
* The original version of this page on the old QPZoo was created by Shraddha Singh.
Digital Signatures (QDS) allow the exchange of classical messages from sender to multiple recipients, with a guarantee that the signature has come from a genuine sender. Additionally, it comes with the properties of transferability, non-repudiation and unforgeability. In contrast, classical digital signatures rely on authentication (taken as an assumption for some QDS protocols) i.e. the message has come from the claimed party; integrity i.e. the message has not been altered (if authentication is confirmed, this property is unforgeability) and non-repudiation (same as QDS). These properties distinguish quantum digital signatures from quantum authentication. Quantum messages can be authenticated but not signed [1], [2]. Note that QDS schemes sign classical messages and not quantum messages.
The protocols that implement this functionality are:
No content has been added to this section, yet!
No content has been added to this section, yet!
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 simplicity, 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).
Unlike classical digital signature schemes which generalize a two party model, QDS protocols always study a three party model as transferability is not inherent and has to be proved in the quantum case. Given this situation, usually, the third party acts as the judge (a verififer) who would gain nothing out of cheating, and hence, cheating strategy is only studied for seller (repudiation) and buyer (forgery). 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 extra some assumptions like trusted omnipotent (one who distributes everyone signatures) 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. Following are a few articles useful for those interested in a more detailed overview of QDS.
Some review papers:
Digital Signatures (QDS) allow the exchange of classical messages from sender to multiple recipients, with a guarantee that the signature has come from a genuine sender. Additionally, it comes with the properties of transferability, non-repudiation and unforgeability. In contrast, classical digital signatures rely on authentication (taken as an assumption for some QDS protocols) i.e. the message has come from the claimed party; integrity i.e. the message has not been altered (if authentication is confirmed, this property is unforgeability) and non-repudiation (same as QDS). These properties distinguish quantum digital signatures from quantum authentication. Quantum messages can be authenticated but not signed [1], [2]. Note that QDS schemes sign classical messages and not quantum messages.
No protocols implement this functionality yet.
acheck
acheck
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 simplicity, 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).
Unlike classical digital signature schemes which generalize a two party model, QDS protocols always study a three party model as transferability is not inherent and has to be proved in the quantum case. Given this situation, usually, the third party acts as the judge (a verififer) who would gain nothing out of cheating, and hence, cheating strategy is only studied for seller (repudiation) and buyer (forgery). 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 extra some assumptions like trusted omnipotent (one who distributes everyone signatures) 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. Following are a few articles useful for those interested in a more detailed overview of QDS.
Some review papers: