A method for linking user identifiers. The method includes receiving, by a linking server and from a company server, a first data structure comprising entries. Each entry comprising a user tag, a first hashed user information, and a second hashed user information. The method includes receiving, by a linking server and from a partner server, a second data structure comprising entries. Each entry comprising a bridge tag, a first hashed bridge information, and a second hashed bridge information. The method includes retrieving, by the linking server and from the first data structure, a first entry of the entries and retrieving, by the linking server and from the second data structure, a first entry of the entries. The method includes linking the user tag of the first entry of the first data structure to the bridge tag of the first entry of the second data structure to generate a first linkage.