Spontaneous anonymous group cryptography
Kai-Sui Liu, Victor K. Wei · 2004
We introduce a new notion called Spontaneous Anonymous Group (SAG) Cryptography. It allows one to spontaneously form a group of users without any collaboration from other parties. It does not require any Trusted Third Party (TTP). Another great advantage is the setup-freeness property. Without any over-powered manager and setup stage, the spontaneous formation of a group is essentially done by specifying a list of public keys associated with the identities of group members. We propose a number of useful cryptographic protocols in SAG cryptography. For example, various threshold SAG signature schemes with additional properties are proposed. Besides, a new SAG signature scheme with linkability property is also proposed. It is the first in the literature to have such property. Finally, a new verifiable encryption for custodian hiding is proposed as well. For each of these protocols, we further suggest some practical applications or scenario which may require these protocols to facilitate.