The present document presents the results of ongoing work to harmonize existing ETSI technical specification on electronic signature formats (TS 101 733 [1] and TS 101 903 [2]) with other internationally recognized standards and related activities. The aim of the present document is to identify the way forward to meet the requirements of European Electronic Signature Directive 1999/93/EC [5] for advanced electronic signatures in a manner which maximizes international interoperability