To produce an European Norm that will specify formats for CMS Advanced Electronic Signatures (CAdES). It will include a CAdES core specification and companion CAdES profiles, including the CAdES Baseline Profile CAdES building blocks part will evolve the latest version of ETSI TS 101 733; CAdES Baseline Profile part will evolve the latest version of ETSI TS 103 173. The work will include the identification and agreement of relevant issues to deal with during the evolution of the aforementioned TSs to EN parts. This part 1 specifies the building blocks with the format for a set of attributes that are added to CMS signatures to become CMS Advanced Electronic Signatures. It also specifies requirements on their construction and incorporation to the signature as signed or unsigned attributes. It also covers the baseline profile.