Vicente Benjumea

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This paper focus on two security services for internet applications: authorization and anonymity. Traditional authorization solutions are not very helpful for many of the Internet applications; however, attribute certificates proposed by ITU-T seems to be well suited and provide adequate solution. On the other hand, special attention is paid to the fact(More)
Purpose – To provide a cryptographic protocol for anonymously accessing services offered on the web. Such anonymous accesses can be disclosed or traced under certain conditions. Design/methodology/approach – The " traceable signature " scheme was used in conjunction with the " privilege management infrastructure ". Findings – The cryptographic primitive(More)
We present a semantic extension to X.509 certificates that allows incorporating new anonymity signature schemes into the X.509 framework. This fact entails advantages to both components. On the one hand, anonymous signature schemes benefit from all the protocols and infrastructure that the X.509 framework provides. On the other hand, the X.509 framework(More)
In this paper we have defined an open framework to support open distributed applications where anonymous transactions based on user privileges play an important role. The goal of the framework is to provide a basis to the application level, and is presented from an open and general perspective where many different implementation schemes can fit. Moreover,(More)
This paper presents fair traceable multi-group signatures (FTMGS), which have enhanced capabilities, compared to group and traceable signatures, that are important in real world scenarios combining accountability and anonymity. The main goal of the primitive is to allow multiple groups that are managed separately (managers are not even aware of the other(More)
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