Clarifications included as part of FHIR-26855 which defines how to request signatures and what the signature means for  Data Query:   The signature  SHALL  represent a  system-level  attestation by the sending organization that they are the source of the information. Task Based Requests and new draft Push mechanism section(see FHIR-33139 ) The signature  SHALL  represent a  human provider  signature on resources attesting that the information is true and accurate. RE the commenter concern:  We would be concerned if the required signature means that the physician must select a null flavor if there isn't information to meet the data request. This situation there isn't information to meet the data request would result in:  Data Query:  empty signed searchset bundle Task Based Requests: If there no data to return, the task cannot be completed ( ~/Davinci-CDEX/output/specification.html#when-the-task-cannot-be-completed). There is no signature requirement in this case.  If the data is partially completed then only the available  signed data is returned. New draft Push mechanism section(see FHIR-33139 ): no information would not be sent RE the comment: "We are also not clear on what attesting to “fulfillment” means – does this mean the information was provided? Wouldn’t the payer receiving the information suffice – why is attestation needed" This is a business requirement. some data consumers may require that the data they receive are signed. For example, the CMS Attachments Rules.