Patent attributes
Systems and methods relating to settlement of securities without revealing ownership including the end owner are described. In some implementations, ownership or control of a security may be managed by using group membership technology to revoke the signing rights of the seller and adding signing rights to the buyer. Group membership with group signatures allow for one group public key and a plurality of private keys, where each private key is associated with a group member. Signatures create by different group members are indistinguishable to verifiers but a group manager is able to determine which member has signed, link member signatures, implement controls and/or limits, and revoke and add signatory capability when needed. In some implementations, revocation of signatory capability is done with the cooperation of a Digital Certificate Authority.