In a group signature [19], any group member can sign on behalf of the group while remaining anonymous, but its identity can be traced in an future dispute investigation. Essentiall...
In 1999, two signature schemes based on the flexible RSA problem (a.k.a. strong RSA problem) were independently introduced: the Gennaro-Halevi-Rabin (GHR) signature scheme and the...
First we revisit three - BGLS, MBGLS and GZZ verifiably encrypted signature schemes [2, 3, 6]. We find that they are all not strong unforgeable.We remark that the notion of existen...
Anonymity services in the EU may be forced by the new EU data retention directive to collect connection data and deanonymise some of their users in case of serious crimes. For this...
In this work we revisit and formally study the notion of proxy cryptography. Intuitively, various proxy functions allow two cooperating parties F (the “FBI”) and P (the “pro...