Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

The KIPS Transactions PartC

How to Exchange Secrets by OT

이용주, 최영일, 이병선

Published Jan 1, 2003• 0 citations
OpenAlex

Abstract

A fair exchange protocol enable two parties to exchange secrets with fairness, so that neither can gain any information advantage by quitting prematurely or otherwise misbehaving. Therefore a fair exchange is the most important for electronic transactions between untrusted parties. To design new fair exchange, after describing basic concepts, definitions and existing protocols and designing a non-interactive OT protocol using ELGamal's public key system, I will design new protocol to support fair exchange. In my designed new protocol, untrusted parties exchange secrets obliviously and verify that their received secrets are true by using transformed Zero Knowledge Interactive Proof extended to duplex. At this time, concerned two parties can't decrypt the other's ciphertext. After all of the steps, two parties can do it. It is the most important to provide perfect fairness and anonymity to untrusted parties in this protocol.

Related papers

Fair exchange with a semi-trusted third party (extended abstract)

Matthew K. Franklin, Michael K. Reiter

We present new protocols for two parties to exchange documents with fairness, i.e., such that no party can gain an advantage by quitting prematurely or otherwise misbehaving.We use a third party that is L'semi-trusted", in the sense that it may misbehave on its own but will not conspire with either of the main parties.In our solutions, disruption by any one of the three parties will not allow the disrupter gain any useful new information about the documents.Our solutions are efficient and can be based on any of several cryptographic assumptions (e.g., factoring, discrete log, graph isomorpbism).We also discuss the application of our techniques to electronic commerce protocols to achieve fair payment.

ACM SIGSAC Conference on Computer and Communications Security (CCS)•Apr 1, 1997•165 citations

Optimistic fair exchange e-commerce protocol based on secret sharing

Changshe Ma, Feiyu Lei, Chen Kefei

A key problem of electronic commerce (for short e-commerce) is fair exchange which guarantees that at the end of the transaction, either both parties in the transaction receive each other's items or none do. A non-interactive optimistic fair exchange e-commerce protocol model based on the publicly verifiable secret sharing is presented. The main idea of our exchange protocol is to interchange verifiable and recoverable keys of the symmetric encryption for participants' items. So it is especially suitable for exchange of large-size items. Furthermore, our protocol is efficient and simple as it does not need interactive proof system which has been adopted by a large quantity of previously proposed fair exchange protocols. Based on a modified (2,2) secret sharing scheme, a concrete non-interactive fair exchange e-commerce protocol is designed.

Journal of Systems Engineering and Electronics•Dec 1, 2006•3 citations

Efficient and practical fair exchange protocols with off-line TTP

Feng Bao, Robert Huijie Deng, Wenbo Mao

We present protocols for fair exchange of electronic data (digital signatures, payment and confidential data) between two parties A and B. Novel properties of the proposed protocols include: 1) offline trusted third party (TTP), i.e., TTP does not take part in the exchange unless one of the parties behaves improperly; 2) only three message exchanges are required in the normal situation; 3) true fair exchange, i.e., either A and B obtain each other's data or no party receives anything useful; no loss can be incurred to a party no matter how maliciously the other party behaves during the exchange. This last property is in contrast to previously proposed protocols with offline TTP ([1] and [21]), where a misbehaving party may get another party's data while refusing to send his document to the other party, and the TTP can provide affidavits attesting to what happened during the exchange. To our knowledge, the protocols presented here are the first exchange protocols which use offline TTP and at the same time guarantee true fair exchange of digital messages. We introduce a novel cryptographic primitive, called the Certificate of Encrypted Message Being a Signature (CEMBS), as the basic building block of the fair exchange protocols. It is used to prove that an encrypted message is a certain party's signature on a public file, without revealing the signature. We also give two examples to show in detail how the certificate can be constructed.

IEEE Symposium on Security and Privacy (S&P)•Nov 27, 2002•295 citations

Fair Exchange with a Semi-Trusted Third Party

Matthew Franklin, Michael K. Reiter

We present new protocols for two parties to exchange documents with fairness, i.e., such that no party can gain an advantage by quitting prematurely or otherwise misbehaving. We use a third party that is L‘semi-trusted”, in the sense that it may misbehave on its own but will not conspire with either of the main parties. In our solutions, disruption by any one of the three parties will not allow the disrupter gain any useful new information about the documents. Our solutions are efficient and can be based on any of several cryptographic assumptions (e.g., factoring, discrete log, graph isomorpbism). We also discuss the application of our techniques to electronic commerce protocols to achieve fair payment.

Computer and Communications Security•Jan 1, 1997•179 citations

Fair Document Exchange Protocol with Confidentiality

Xiaoxin Ye, Zhenfu Cao, Xiaohui Liang

The paper proposes a new fair document exchange protocol.In such a fair exchange scenario,each party owns a valuable secret message and they want to exchange their secrets in a fairness way so that at the end of the transaction,either both of them get the other’s secret or neither of them gets the other’s secret.Compared with previous fair exchange protocols,the protocol holds confidentiality,that is,except the two participating party,no one even the Trusted Third Party(TTP) can get exchanged items.

Jisuanji gongcheng•Jan 1, 2009•1 citation

Fair Exchange Protocol with Distributed Semi-trusted Third Party

Futai Zhang

The techniques of verifiable secret sharing and verifiable encryption are used in the construction of two party fair exchange protocols.The novelty of the construction lies in the introduction of the distributed semi-trusted third party.Compared to the previous fair exchange protocols with a single semi-trusted third party,the newly constructed fair exchange protocol can further guarantee the security and fairness of the transaction due to the existence of the distributed semi-trusted third party.

Jisuanji gongcheng•Jan 1, 2006•0 citations
A fair exchange protocol enable two parties to exchange secrets with fairness, so that neither can gain any information advantage by quitting prematurely or otherwise misbehaving. Therefore a fair exchange is the most important for electronic transactions between untrusted parties. To design new fair exchange, after describing basic concepts, definitions and existing protocols and designing a non-interactive OT protocol using ELGamal's public key system, I will design new protocol to support fair exchange. In my designed new protocol, untrusted parties exchange secrets obliviously and verify that their received secrets are true by using transformed Zero Knowledge Interactive Proof extended to duplex. At this time, concerned two parties can't decrypt the other's ciphertext. After all of the steps, two parties can do it. It is the most important to provide perfect fairness and anonymity to untrusted parties in this protocol.
We present new protocols for two parties to exchange documents with fairness, i.e., such that no party can gain an advantage by quitting prematurely or otherwise misbehaving.We use a third party that is L'semi-trusted", in the sense that it may misbehave on its own but will not conspire with either of the main parties.In our solutions, disruption by any one of the three parties will not allow the disrupter gain any useful new information about the documents.Our solutions are efficient and can be based on any of several cryptographic assumptions (e.g., factoring, discrete log, graph isomorpbism).We also discuss the application of our techniques to electronic commerce protocols to achieve fair payment.
A key problem of electronic commerce (for short e-commerce) is fair exchange which guarantees that at the end of the transaction, either both parties in the transaction receive each other's items or none do. A non-interactive optimistic fair exchange e-commerce protocol model based on the publicly verifiable secret sharing is presented. The main idea of our exchange protocol is to interchange verifiable and recoverable keys of the symmetric encryption for participants' items. So it is especially suitable for exchange of large-size items. Furthermore, our protocol is efficient and simple as it does not need interactive proof system which has been adopted by a large quantity of previously proposed fair exchange protocols. Based on a modified (2,2) secret sharing scheme, a concrete non-interactive fair exchange e-commerce protocol is designed.
We present protocols for fair exchange of electronic data (digital signatures, payment and confidential data) between two parties A and B. Novel properties of the proposed protocols include: 1) offline trusted third party (TTP), i.e., TTP does not take part in the exchange unless one of the parties behaves improperly; 2) only three message exchanges are required in the normal situation; 3) true fair exchange, i.e., either A and B obtain each other's data or no party receives anything useful; no loss can be incurred to a party no matter how maliciously the other party behaves during the exchange. This last property is in contrast to previously proposed protocols with offline TTP ([1] and [21]), where a misbehaving party may get another party's data while refusing to send his document to the other party, and the TTP can provide affidavits attesting to what happened during the exchange. To our knowledge, the protocols presented here are the first exchange protocols which use offline TTP and at the same time guarantee true fair exchange of digital messages. We introduce a novel cryptographic primitive, called the Certificate of Encrypted Message Being a Signature (CEMBS), as the basic building block of the fair exchange protocols. It is used to prove that an encrypted message is a certain party's signature on a public file, without revealing the signature. We also give two examples to show in detail how the certificate can be constructed.
We present new protocols for two parties to exchange documents with fairness, i.e., such that no party can gain an advantage by quitting prematurely or otherwise misbehaving. We use a third party that is L‘semi-trusted”, in the sense that it may misbehave on its own but will not conspire with either of the main parties. In our solutions, disruption by any one of the three parties will not allow the disrupter gain any useful new information about the documents. Our solutions are efficient and can be based on any of several cryptographic assumptions (e.g., factoring, discrete log, graph isomorpbism). We also discuss the application of our techniques to electronic commerce protocols to achieve fair payment.
The paper proposes a new fair document exchange protocol.In such a fair exchange scenario,each party owns a valuable secret message and they want to exchange their secrets in a fairness way so that at the end of the transaction,either both of them get the other’s secret or neither of them gets the other’s secret.Compared with previous fair exchange protocols,the protocol holds confidentiality,that is,except the two participating party,no one even the Trusted Third Party(TTP) can get exchanged items.
The techniques of verifiable secret sharing and verifiable encryption are used in the construction of two party fair exchange protocols.The novelty of the construction lies in the introduction of the distributed semi-trusted third party.Compared to the previous fair exchange protocols with a single semi-trusted third party,the newly constructed fair exchange protocol can further guarantee the security and fairness of the transaction due to the existence of the distributed semi-trusted third party.