Sietse Ringers

  • Citations Per Year
Learn More
Recently an unlinkable version of the U-Prove attributebased credential scheme was proposed at Financial Crypto ’14 [9]. Unfortunately, the new scheme is forgeable: if sufficiently many users work together then they can construct new credentials, containing any set of attributes of their choice, without any involvement of the issuer. In this note we show(More)
Self-blindable credential schemes allow users to anonymously prove ownership of credentials. This is achieved by randomizing the credential before each showing in such a way that it still remains valid. As a result, each time a different version of the same credential is presented. A number of such schemes have been proposed, but unfortunately many of them(More)
In [HK14] an unlinkable version of the U-Prove attribute-based credential scheme is proposed. Unfortunately, the new scheme is forgeable: if sufficiently many users work together then they can construct new credentials, containing any set of attributes of their choice, without any involvement of the issuer. In this note we show how they can achieve this and(More)
An attribute-based credential scheme allows a user, given a set of attributes, to prove ownership of these attributes to a verifier, voluntarily disclosing some of them while keeping the others secret. A number of such schemes exist, of which some additionally provide unlinkability: that is, when the same attributes were disclosed in two transactions, it is(More)
  • 1