Execution environment and gatekeeper arrangement

A computer-implemented method performed by a gatekeeper which is part of a computer system, the method comprising:

• enforcing an input output policy on a first execution environment by interposing on all communication to and from the first execution environment by forwarding, modifying or dropping individual ones of the communications according to a policy, wherein the enforcing is done using a separation mechanism of the computer system;
• such that outgoing communications from the first execution environment are sent out of the computer system according to the policy and incoming communications to the first execution environment are accepted according to the policy;
• and
• computing evidence of attestation both for the application specific code and the policy using an attestation mechanism of the computer system.

One or more device-readable media with device-executable instructions that, when executed by a computer system, direct the computing system to perform for performing operations comprising:

• enforcing an input output policy on a first execution environment by interposing on all communication to and from the first execution environment by forwarding, modifying or dropping individual ones of the communications according to a policy, wherein the enforcing is done using a separation mechanism of the computer system;
• sending outgoing communications from the first execution environment out of the computer system according to the policy and accepting incoming communications to the first execution environment according to the policy;
• and
• computing evidence of attestation both for the application specific code and the policy using an attestation mechanism of the computer system.