Abstract: The subject matter of this specification can be implemented in, among other things, methods, systems, and computer-readable storage media. A method can include receiving a first request to retrieve an identifier token associated with a user account. The method can further include generating a first alphanumeric sequence associated with the user account and performing a randomization procedure on the first alphanumeric sequence to generate a second alphanumeric sequence. The method can further include generating the identifier token for a subscriber associated with the user account to provide to a second device. The method can further include receiving, from a third device, a second request including a second identifier token having a third alphanumeric sequence, the second request being associated with performing an action using sensitive data associated with the user account. The method can further include sending data including the second request to the third device.