PROTECTING ACCESS TO INFORMATION IN ONLINE INTERACTIONS

This disclosure relates to preserving the privacy of users and preventing access to information of other entities. In one aspect, a method includes receiving, from a client device, a content request including request signals specifying user group identifiers that each identify a user group that includes a user of the client device. One or more user group identifiers that satisfy a first k-anonymity process are identified. Selection parameter elements that each include data indicating a respective digital component and a selection parameter for the respective digital component are received from one or more first content platforms. At least a portion of the selection parameters and, for each selection parameter, data identifying the first content platform from which the selection parameter was received are transmitted to a second content platform. Data specifying a given first content platform selected based on the selection parameters is received from the second content platform.