Abstract: Prevention of unpermitted use of enabling bits is achieved by sealing the enabling bits to an environment in such a way that the bits can only be unsealed by or from the environment, and by using an isolation mechanism to isolate the environment from other environments on the machine on which the environment operates. The environment is trusted not to use the enabling bits except in accordance with a set of rules governing the bits. The enabling bits may be a decryption key for DRM-protected content, and the rules may be a license governing the use of that content. Trust that the enabling bits will not be misused is established by trusting the environment not to use the enabling bits contrary to the rules, trusting the isolation mechanism to isolate the environment, and trusting the unsealing mechanism only to unseal the bits for the environment.