EMV 3-D Secure (3DS) - Payment Authentication Protocol 4.2.1: 4.2.1 App processing screen (Req 4.1 to 4.12)

For the AReq/ARes exchange the 3DS SDK builds a processing screen with no design element other than the processing graphic and, where requested, the DS logo, which it stores (Req 4.1 to 4.4), and the 3DS Requestor App shows that screen for the whole AReq/ARes cycle and for at least two seconds (Req 4.5, 4.6); for the CReq/CRes exchange the SDK uses the device operating system's default processing graphic, again with no other design element and the DS logo only where requested, and displays it for the whole CReq/CRes cycle and for at least two seconds (Req 4.7 to 4.12). The UI format chosen (native or HTML) stays the same for every exchange of the challenge.