Résumé: Recently, Li et al. proposed two group-oriented (t, n) threshold digital signature schemes with traceable signers, which allow any t out of n members of a group to sign messages on behalf of the group. For achieving the accountability if necessary, their schemes also provide the ability to trace back for finding out the participant signers. However, this article will demonstrate two attacks (including the forgery and the masquerade attacks) to show that their schemes cannot fulfill the claimed security requirements.

Langue: Anglais