18. The computer storage media of claim 16 , wherein the identifier comprises a business name, and wherein comparing the identifier to the set of tenant identifiers comprises comparing the business name to businesses who are tenants of the cloud service.
16. One or more computer-readable storage media including computer-executable instructions that, when executed, cause at least one processor to conceal tenancy in a multi-tenant cloud service participating in a federated identity platform by: receiving a request for a document from a first entity by the cloud service, the request including an identifier associated with a second entity; redirecting the first entity to an identity provider for authentication; receiving a token from the identity provider indicating authentication of the first entity by the identity provider; comparing the identifier to a set of tenant identifiers each corresponding to one of a plurality of tenants to determine whether the second entity is one of the plurality of tenants; dynamically generating a fictitious document in response to the request after determining that the second entity is not one of the plurality of tenants; digitally signing the generated fictitious document with a certificate for the second entity; and sending the signed fictitious document to the first entity.