ISO/IEC 20009-2:2013 specifies anonymous entity authentication mechanisms based on signatures using a group public key in which a verifier verifies a group signature scheme to authenticate the entity with which it is communicating, without knowing this entity's identity.

ISO/IEC 20009-2:2013 provides:

• a general description of an anonymous entity authentication mechanism based on signatures using a group public key;
• a variety of mechanisms of this type.

ISO/IEC 20009-2:2013 describes:

• the group membership issuing processes;
• anonymous authentication mechanisms without an online Trusted Third Party (TTP);
• anonymous authentication mechanisms involving an online TTP.

Furthermore, ISO/IEC 20009-2:2013 also specifies:

• the group membership opening process (optional);
• the group signature linking process (optional).