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Reactively Simulatable Certified Mail.

Birgit Pfitzmann, Matthias Schunter, Michael Waidner

Published Jan 1, 2006• 2 citations
OpenAlex

Abstract

Abstract Certified mail is the fair exchange of a message for a receipt, i.e., the recipient gets the message if and only if the sender gets a receipt. It is an important primitive for electronic commerce and other atomicity services. Certified-mail protocols are known in the literature, but there was no rigorous definition yet, in particular for optimistic protocols and for many interleaved executions. We provide such a definition via an ideal system and show that a specific real certified-mail protocol is as secure as this ideal system in the sense of reactive simulatability in the standard model of cryptography and under standard assumptions. As certified mail without any third party is not practical, we consider optimistic protocols, which involve a third party only if one party tries to cheat. The real protocol resembles prior protocols, but we had to use a different cryptographic primitive to achieve simulatability. The communication model is synchronous. This proof first demonstrated that a cryptographic multi-step protocol can fulfil a general definition of reactive simulatability enabling concurrent composition. We also first showed how formal-method style reasoning can be applied over the ideal system in a cryptographically sound way. Moreover, the treatment of multiple protocol runs and their modular proof in spite of the use of common cryptographic primitives for all runs can be seen as a first example of what is now known as joint-state composition.

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With a certified-mail protocol, one fairly exchanges a message for a receipt. No satisfactory protocols without any third party are possible, hence optimistic protocols are the best one can hope for. Here a third party is only involved if one party tries to cheat. Certified-mail protocols are known in the literature, but there was no rigorous definition yet, in particular for the optimistic case and for many interleaved executions. We provide two such definitions. One defines individual integrity and secrecy requirements. The other defines an ideal system and uses a general simulatability definition. We show the relation between the definitions, present an efficient protocol, and prove its security in detail. Apart from the intrinsic benefits of provably secure certified mail, this paper serves as an example that a serious-sized practical protocol can be rigorously proven with respect to a general simulatability definition and an abstract specification accessible to formal me...

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Abstract:- An efficient and secure protocol in certified e-mail delivery is proposed in this paper. With the widespread use of public Internet, communication via electronic mail (e-mail) becomes a convenience application instead of traditional manuscript letter. People can easily append his/her digital signature to the e-mail in order to achieve the goal of non-repudiation of origin. However, the evidence of receipt still relies on the willingness of the recipient in the standard e-mail service. Hence, the recipient has no responsible for the received e-mail. In this paper, we present an efficient and secure protocol in fair certified e-mail delivery (CEMD). Our protocol efficiently provides non-repudiation of origin and receipt in the fair manner. In other words, the sender can obtain the irrefutable receipt if and only if the recipient gets the certified e-mail from the sender, otherwise, neither of them. Moreover, the proposed CEMD is efficiently in sending the other mails to the same recipient by using the pre-computation function. As the evaluations of computational cost and communication overhead, our protocol is cost-effective and efficient than other relevant protocols.

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•Jan 1, 2005•0 citations
Abstract Certified mail is the fair exchange of a message for a receipt, i.e., the recipient gets the message if and only if the sender gets a receipt. It is an important primitive for electronic commerce and other atomicity services. Certified-mail protocols are known in the literature, but there was no rigorous definition yet, in particular for optimistic protocols and for many interleaved executions. We provide such a definition via an ideal system and show that a specific real certified-mail protocol is as secure as this ideal system in the sense of reactive simulatability in the standard model of cryptography and under standard assumptions. As certified mail without any third party is not practical, we consider optimistic protocols, which involve a third party only if one party tries to cheat. The real protocol resembles prior protocols, but we had to use a different cryptographic primitive to achieve simulatability. The communication model is synchronous. This proof first demonstrated that a cryptographic multi-step protocol can fulfil a general definition of reactive simulatability enabling concurrent composition. We also first showed how formal-method style reasoning can be applied over the ideal system in a cryptographically sound way. Moreover, the treatment of multiple protocol runs and their modular proof in spite of the use of common cryptographic primitives for all runs can be seen as a first example of what is now known as joint-state composition.
With a certified-mail protocol, one fairly exchanges a message for a receipt. No satisfactory protocols without any third party are possible, hence optimistic protocols are the best one can hope for. Here a third party is only involved if one party tries to cheat. Certified-mail protocols are known in the literature, but there was no rigorous definition yet, in particular for the optimistic case and for many interleaved executions. We provide two such definitions. One defines individual integrity and secrecy requirements. The other defines an ideal system and uses a general simulatability definition. We show the relation between the definitions, present an efficient protocol, and prove its security in detail. Apart from the intrinsic benefits of provably secure certified mail, this paper serves as an example that a serious-sized practical protocol can be rigorously proven with respect to a general simulatability definition and an abstract specification accessible to formal me...
As security enhanced systems for standard e-mail, certified e-mail schemes guarantee the fair exchange of a digital message with the corresponding receipt between two mistrusted parties. That is, the intended receiver gets the e-mail content if and only if the e-mail sender obtains an irrefutable receipt issued by the receiver, which could be used to prove that the message has been delivered to the receiver. A number of such protocols have been proposed in recent years. However, most of them are not suitable for mobile networks, since many intricate cryptographic primitives are involved so that considerable overheads are introduced. In this paper, we present a novel simple protocol for certified e-mail delivery. Technical discussions are provided to show that our new solution is both secure and very efficient so that it is truly suitable for wireless mobile users, where the available devices usually have limited resources on computation, communication, storage, and power supply.
Electronic mail delivery is one of the most important and desirable services, by which the intended recipient will get the mail if and only if the mail originator receives a valid and irrefutable proof of the receipt. The idea of conditional trusted third party has been developed on the basis of semi-trusted TTP and a suite of acceptable conditions is given. A new practical protocol for certified e-mail is presented, which can guarantee acceptable fair with interception of conditional TTP. More, the evidence in the new protocol is publicly verifiable without any restrictions on the type of signature and encryption algorithms.
As a value-added service to deliver important data over the Internet with guaranteed receipt for each successful delivery, certified email has been discussed for years and a number of research papers appeared in the literature. But most of them deal with the two-party scenarios, i.e., there are only one sender and one recipient. In some ap- plications, however, the same certified message may need to be sent to a set of recipients. In this paper, we present two optimized multi-party certified email protocols. Both of them have three major features. (1) A sender could notify multiple recipients of the same information while only those recipients who acknowledged are able to get the information. (2) Both the sender and the recipients can end a protocol run at any time without breach of fairness. (3) The exchange protocols are optimized, each of which has only three steps, and the TTP will not be involved unless an exception (e.g., a network failure or a party's misbehavior) occurs.
Abstract:- An efficient and secure protocol in certified e-mail delivery is proposed in this paper. With the widespread use of public Internet, communication via electronic mail (e-mail) becomes a convenience application instead of traditional manuscript letter. People can easily append his/her digital signature to the e-mail in order to achieve the goal of non-repudiation of origin. However, the evidence of receipt still relies on the willingness of the recipient in the standard e-mail service. Hence, the recipient has no responsible for the received e-mail. In this paper, we present an efficient and secure protocol in fair certified e-mail delivery (CEMD). Our protocol efficiently provides non-repudiation of origin and receipt in the fair manner. In other words, the sender can obtain the irrefutable receipt if and only if the recipient gets the certified e-mail from the sender, otherwise, neither of them. Moreover, the proposed CEMD is efficiently in sending the other mails to the same recipient by using the pre-computation function. As the evaluations of computational cost and communication overhead, our protocol is cost-effective and efficient than other relevant protocols.
Abstract. As a value-added service for standard email systems, a certified email scheme allows a sender to deliver a message to a receiver in a fair way in the sense that either the sender obtains a receipt from the receiver and the receiver accesses the content of the email simultaneously, or neither party gets the expected item. In this paper, we first point out some weaknesses in several existing schemes. Then, we present two generic optimistic certified email schemes with transparent TTP. Our schemes are not only fair, but also support timeliness in two flavors: one scheme supports weak timeliness but with stateless TTP, while the other guarantees (strong) timeliness though only supports weak stateless TTP. Technical discussion and comparison are provide to show that our schemes are both secure and efficient, compared with the-state-of-art in this field.