PCI PIN Security v3.1

PIN Security Requirements:
15-3 Mechanisms must exist to prevent a non-authorized KDH from performing key transport, key exchange, or key establishment with POIs. POIs and key-distribution hosts (KDHs) using public-key schemes must validate authentication credentials of other such devices involved in the communication immediately prior to any key transport, exchange, or establishment. Mutual authentication of the sending and receiving devices must be performed.
Note: Examples of this kind of validation include ensuring the SCD serial number is listed in a table of "permitted" devices, checking current certificate revocation lists or embedding valid authorized KDH certificates in devices, and disallowing communication with unauthorized KDHs, as delineated by techniques defined in the Technical FAQs for PCI PTS POI Security Requirements.
Testing Procedures:
15-3.a Examine documented procedures to confirm they define procedures for mutual authentication of the sending and receiving devices, as follows: 

15-3.b Interview applicable personnel to verify that mutual authentication of the sending and receiving devices is performed, as follows: 

PIN Security Requirements:
15-4 Key-establishment and distribution procedures must be designed such that:
Within an implementation design, there shall be no means available for “man-in-the-middle” attacks—e.g., through binding of the KDH certificate upon the initial communication.
System implementations must be designed and implemented to prevent replay attacks—e.g., through the use of random nonces and time stamps as noted in ANSI TR 34.
Testing Procedures:
15-4 Examine system and process documentation to verify that key-establishment and distribution procedures are designed such that: 

PIN Security Requirements:
15-5 Key pairs generated external to the device that uses the key pair must be securely transferred and loaded into the device and must provide for key protection in accordance with this document. That is, the secrecy of the private key and the integrity of the public key must be ensured. The process must ensure that once keys are injected, they are no longer available for injection into other POI devices—i.e., key pairs are unique per POI device.
Testing Procedures:
15-5 If key pairs are generated external to the device that uses the key pair, perform the following: