International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 01 May 2015

Stephen R. Tate, Roopa Vishwanathan
ePrint Report ePrint Report
Attribute-based signatures, introduced by Maji \\emph{et al.}, are

signatures that prove that an authority has issued the signer

``attributes\'\' that satisfy some specified predicate. In existing

attribute-based signature schemes, keys are valid indefinitely once

issued. In this paper, we initiate the study of incorporating time into

attribute-based signatures, where a time instance is embedded in every

signature, and attributes are restricted to producing signatures with

times that fall in designated validity intervals. We provide

three implementations that vary in granularity of assigning validity

intervals to attributes, including a scheme in which each attribute

has its own independent validity interval, a scheme in which all

attributes share a common validity interval, and a scheme in which

sets of attributes share validity intervals. All of our schemes provide anonymity to a signer, hide the attributes used to create the signature, and provide collusion-resistance between

users.

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