In an example, there is disclosed a computing apparatus, comprising: a trusted execution environment (TEE); and a security engine operable to: identify a key negotiation for an encrypted connection between a first device and a second device; request a service appliance key for the key negotiation; receive the service appliance key; and perform a service appliance function on traffic between the first device and the second device. There is also disclosed a method of providing the security engine, and a computer-readable medium having stored thereon executable instructions for providing the security engine.