2.2.1.3.2 The Proximity Challenge Message

A proximity challenge message contains four sections:

Header: Contains the protocol version supported by the transmitter and the message type. The protocol version MUST be set to 0x03 and the message type for proximity challenge messages is 0x04.

Sequence number: This 8-bit sequential number. This value MUST be incremented by one every time the proximity challenge message is sent to the receiver.

Session ID: Contains the session ID. The transmitter MUST send the same 128-bit session ID that it sent to the receiver in the registration response message.

Challenge value (Nonce): A 128-bit, random challenge value selected by the transmitter.


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ProtocolVersion

MessageType

SequenceNumber

SessionID (16 bytes)

...

...

...

Nonce (16 bytes)

...

...

...

ProtocolVersion (1 byte): Contains the protocol version supported by the transmitter. The protocol version MUST be set to 0x03.

MessageType (1 byte): Contains the message type. The message type for proximity challenge messages is 0x04.

SequenceNumber (1 byte): Contains the sequence number. This 8-bit sequential number MUST be incremented by one every time the proximity challenge message is sent to the receiver.

SessionID (16 bytes): Contains the session ID. The transmitter MUST send the same 128-bit session ID that it sent to the receiver in the registration response message.

Nonce (16 bytes): Contains the nonce. Must be set to a 128-bit random value selected by the transmitter.