Obscuring information in messages to be exchanged over a communications network. In one aspect, the information comprises path name information and parameters for use in a Uniform Resource Locator (“URL”). In another aspect, the information comprises links and parameters used in forms, where hidden parameters are removed from a form and used as URL parameters. A compression dictionary is used to create a compressed form of the information. An identifier of the dictionary and an error detection code (such as a checksum) computed over the compressed information are concatenated with the compressed information, and this is encoded for sending on an outbound message. The original information is then recovered from an inbound message which contains the obscured information by reversing the processing used for the obscuring.