The current document describes systems and methods that provide access controls in a system of interconnected services such as an online service platform. In various implementations, the system maintains contextual information associated with tokenized data. In additional implementations, data brokers authorize access to detokenized data by comparing the context of the data to the context of the service requesting the data. In yet additional implementations, the system maintains contextual information associated with requests that are processed within the system. When a request is made to a particular service, the particular service can use the identity of the requester, the context of the request, and the context of the data to determine whether the request is authorized. In some implementations, the integrity of contextual information is protected using a digital signature.