Method and apparatus for detecting that an attacker has sent one or more messages to a receiver node

A method comprising:

• storing, at a sender node, at least a portion of each of a plurality of messages sent by the sender node to a receiver node in a memory device;
• receiving, at the sender node, an integrity check message from the receiver node comprising an indication of a value of n, where n is an integer value greater than one;
• retrieving, at the sender node, at least a portion of the nth message sent by the sender node to the receiver node from the memory device;
• and
• sending, from the sender node, a reply message to the receiver node including the at least a portion of the nth message sent by the sender node to the receiver node.

Apparatus for detecting that an attacker has sent one or more messages to a receiver node, the apparatus comprising a processor and a memory device, wherein the processor is configured to

• store, at the receiver node, at least a portion of an nth message received by the receiver node from a sender node in the memory device;
• send, from the receiver node, an integrity check message to the sender node comprising an indication of the value of n, where n is an integer value greater than one;
• receive, at the receiver node, a reply message from the sender node including at least a portion of the nth message sent by the sender node to the receiver node;
• and
• compare the at least a portion of the nth message sent by the sender node to the receiver node with the nth message received by the receiver node from the sender node stored in the memory device.

Apparatus comprising a processor and a memory device, wherein the processor is configured to:

• store, at a sender node, at least a portion of each of a plurality of messages sent by the sender node to a receiver node in a memory device;
• receive, at the sender node, an integrity check message from the receiver node comprising an indication of a value of n, where n is an integer value greater than one;
• retrieve, at the sender node, at least a portion of the nth message sent by the sender node to the receiver node from the memory device;
• and
• send, from the sender node, a reply message to the receiver node including the at least a portion of the nth message sent by the sender node to the receiver node.