Security techniques for a peripheral component interconnect (pci) express (pcie) system

A method of providing secure communications between devices on either end of a Peripheral Component Interconnect (PCI) express (PCIE) link, comprising:

• prepending a transport layer protocol (TLP) prefix onto a TLP packet, wherein the TLP prefix comprises an indication that the TLP packet is a secure packet;
• encrypting a payload of the TLP packet;
• and
• sending the TLP packet from a first one of the devices over the PCIE link to the other one of the devices.

A Peripheral Component Interconnect (PCI) express (PCIE) system comprising:

• a host device comprising:
• a root complex;
• a host encryption/decryption engine;
• and
• a host interface;
• a PCIE link coupled to the host interface;
• and
• an endpoint device comprising:
• an endpoint interface coupled to the PCIE link;
• and
• an endpoint encryption/decryption engine;
• wherein the root complex is configured to:
• prepend a transport layer protocol (TLP) prefix onto a TLP packet,
• wherein the TLP prefix comprises:
• an indication that the TLP packet is a secure packet;
• and
• a counter value representing a monotonically-increasing counter to detect replay attacks;
• encrypt a payload of the TLP packet;
• append a cryptographically-generated identifier calculated at least in part on a portion of the TLP packet to the TLP packet;
• and
• send the TLP packet from a first one of the host device and the endpoint device over the PCIE link to the other one of the host device and the endpoint device.