Cryptology and Network Security

Volume 4856 of the series Lecture Notes in Computer Science pp 265-281

Anonymity 2.0 – X.509 Extensions Supporting Privacy-Friendly Authentication

  • Vicente BenjumeaAffiliated withComputer Science Dept., University of Malaga
  • , Seung Geol ChoiAffiliated withComputer Science Dept., Columbia University
  • , Javier LopezAffiliated withComputer Science Dept., University of Malaga
  • , Moti YungAffiliated withGoogle & Computer Science Dept., Columbia University

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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 incorporates anonymity as a very interesting new feature. This semantic extension is part of a system that provides user’s controlled anonymous authorization under the X.509 framework. Additionally, the proposal directly fits the much active Identity 2.0 effort, where anonymity is a major supplementary feature that increases the self-control of one’s identity and privacy which is at the center of the activity.


Anonymous authentication X.509 certificates group signatures ring signatures traceable signatures