This part of ISO/IEC20008 specifies anonymous digital signature mechanisms, in which a verifier makes use of a group public key to verify a digital signature.
It provides
a general description of an anonymous digital signature mechanism using a group public key, and
a variety of mechanisms that provide such anonymous digital signatures.
For each mechanism, this part of ISO/IEC20008 specifies
the process for generating group member signature keys and a group public key,
the process for producing signatures,
the process for verifying signatures,
the process for opening signatures (if the mechanism supports opening),
the process for linking signatures (if the mechanism supports linking), and
the process for revoking group members.