1. At least one non-transitory computer-readable medium comprising instructions that, in response to execution by one or more processing devices of a computing device, cause the computing device to: obtain, from a dimension authority, one or more dimensions, each dimension including an attribute of a user or attribute of a computing environment associated with the user and a population count of users or computing environments associated with users that share that attribute, wherein the one or more dimensions are obtained based in part on a comparison of an anonymity index to an anonymity threshold associated with the user or the computing environment associated with the user, the anonymity index based in part on a sum of a plurality of a function of population counts for the one or more dimensions; without enabling identification of the user or users, verify authenticity of the one or more dimensions by verifying a public key against a private key used by a trusted execution environment of a user device or device of the computing environment associated with the user, to sign the one or more dimensions, wherein to verify authenticity includes an authentication exchange, wherein at least one message in the authentication exchange by the computing device is signed with the private key and wherein the trusted execution environment comprises enforced thread and memory access isolation; and generate content targeted towards the user or computing environment attribute of the one or more dimensions.