argument: PED
A1 "Confidentiality and integrity of customers' PIN is assured" {
	supported by
		F1 "PED has a tamper proofing mechanism"
		F2 "There is a tamper proof sealed box around the PED"
	warranted by
		A2 "The tamper proofing mechanism guarantees that attempts to
tamper the PED sealed box will cause data in transit to be deleted, 
lost or overridden (depending on the mechanism implemented)" with !F1  {
		warranted by
			DK1 "Defeating the tamper proofing mechanism
requires more than 10 hours effort"
			DK2 "Defeating the tamper proofing mechanism cost
more than $25,000"
		}
		A3 "The PED sealed box is really tamper proof" {
			supported by
				F3 "Communication outside the PED box is encrypted"
			warranted by
				DK3 "There is no need for an expensive EMV protocol
implementation to enforce encrypted communication 
inside the PED box"
		}
}