In one embodiment, a method includes receiving, at a privacy transaction platform server, from a transaction network server, a transaction approval request associated with a user device and a requesting server including proffered transaction strings and proffered server properties associated with the requesting server, retrieving a privacy transaction record associated with the user device including tagged transaction strings and server properties associated with a provider server, determining that there is a transaction string match between the proffered transaction strings and the corresponding tagged transaction strings, determining that there is a server match between the requesting server and the provider server based on a validity metric for the transaction approval request exceeding a specified confidence threshold based on an analysis of the proffered server properties and the provider server properties, and transmitting, to the transaction network server, a validation response approving the requested transaction.