A Secure Modified ID-Based Undeniable Signature Scheme

Verifiable Pairing and its Applications. In Chae Hoon Lim and Moti Yung, editors, Information Security Applications: 5th International Workshop, WISA 2004, Jeju Island, Korea, August 23-25, 2004, Revised Selected Papers, volume 3325 of Lecture Notes in Computer Science, pp. 170-187. (http://www.springerlink.com/index/C4QB7C13NL0EY5VN) which contains an improved and generalized result of this paper

Secure electronic commerce with mobile agents

Online transactions using mobile agents need secure protocols to help the mobile agents to accomplish the transactions initiated by a client in an electronic commerce. However, the mobile agent could encounter hostile environment. For example, a server may compromise the mobile agent and try to obtain private information of the client. A solution to tackle this issue has been proposed. However, the existing solution is implemented using RSA signatures that result in long signatures and heavy workloads for the mobile agent. Mobile agents will migrate from the client to a server and from one server to other servers in order to accomplish the client?s transaction plan. Therefore, it will be interesting to re-tackle this issue. We present a new scheme for secure transactions using mobile agents in potentially hostile environments. This transaction scheme is implemented by using a new undetachable signature scheme. The new undetachable signature protocol utilizes short signatures, which is desirable for low-bandwidth and efficient mobile communications

Secure e-transactions using mobile agents with agent broker

This paper presents an e-transactions protocol using mobile agents. However, when mobile agents travel to a number of servers for searching optimal purchase for the underlying customer, the mobile codes should be protected. We integrate a secure signature algorithm with the e-transaction algorithm to maintain the security. In addition, an agent broker is involved in the algorithm that will help to reduce the communications among the mobile agents, the customer, and the servers. We have presented security and privacy analysis for the proposed protocol

Practical fair anonymous undeniable signatures

We present a new model for undeniable signatures: fair-anonymous undeniable signatures. This protocol can not only preserve the privacy of the signer (i.e. anonymity) but also track the illegal utilization of the valid signatures. In addition, our model prevents the trusted centre from forging a valid signature for any signer

Uma solução de assinatura digital curta especial baseada em uma variação do DSA gerada em dispositivo pessoal

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.O presente trabalho apresenta uma solução para geração de assinatura digital curta com características especiais, baseada em uma variação do algoritmo DSA. A assinatura é gerada com apenas 32 bits em um dispositivo pessoal que opera sem conectividade com o computador, sendo curta o suficiente para ser informada manualmente pelo usuário, através do teclado, para validação. A aparente vulnerabilidade ocasionada pela redução no tamanho da assinatura é contornada por um protocolo criptográfico especialmente projetado. O contexto da solução aqui apresentada visa garantir, através da assinatura digital, o não-repúdio nas transações bancárias realizadas de forma eletrônica pelo correntista através do Internet Banking. This work presents a solution for generation of short digital signature with special features based on a variation of the DSA algorithm. The signature, generated in a personal device without any connectivity with the client's computer, is only 32-bit long, being short enough to be manually informed by a human through a keyboard for validation. The apparent weakness caused by the exceptionally large reduction in the size of the signature is overcome by a specially designed cryptographic protocol. The context of our solution aims to assure, through the use of digital signatures, the nonrepudiation requirement in Internet Banking transactions