A method may include generating a proxy auto-configuration file including a function and a hash value associated with a resource. The hash value may be determined based on an identifier of the resource. The proxy auto-configuration file may include the hash value instead of a plaintext value of the identifier to obscure the plaintext value of the identifier. The proxy auto-configuration file including the function and the hash value may be sent to at least enable the function to be invoked by a web browser at one or more clients. The function may be configured to respond to being invoked by the web browser by determining, based on the hash value, whether to bypass a proxy server when accessing the resource. Related systems and computer program products are also provided.