Method of forming high security fastener with internal shroud buckled retainer

A method of forming a fastener comprising the steps of:

• providing a fastener body orientated about a central axis;
• said fastener body having a tool engaging portion to which a driving torque may be applied, a threaded fastening portion configured and arranged to mate with a corresponding threaded element, and a shroud-receiving body portion orientated about said central axis;
• providing a shroud;
• mounting said shroud concentrically on said shroud-receiving body portion such that an outer surface of said shroud faces an inner surface of said shroud-receiving body portion;
• axially aligning an annular groove in said inner surface of said shroud receiving body portion with a buckling portion of said shroud;
• restraining said shroud or said fastener body from moving in a first direction along said central axis;
• applying an axial force to the other of said shroud or said fastener body in said first direction such that said buckling portion of said shroud buckles outwardly into said annular groove of said shroud-receiving body portion under said applied axial force to form an axially-buckled radially-extending annular protrusion extending transverse to said central axis and disposed in said annular groove;
• such that said shroud is restrained from movement in at least one axial direction along said central axis.