High security fastener with buckled shroud 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 inner surface of said shroud faces an outer surface of said shroud-receiving body portion;
• axially aligning an annular groove in said inner surface of said shroud or said outer surface of said shroud receiving body portion with a buckling portion of said other of said shroud or said shroud-receiving body portion;
• 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 buckles inwardly or outwardly into said annular groove under said applied axial force to form a substantially arch-shaped axially-buckled radially-extending annular protrusion extending transverse to said central axis and having at least an annular apex disposed in said annular groove;
• such that said shroud is restrained from movement in at least one axial direction along said central axis that is opposite to said first axial direction and such that said shroud is supported in rotatable relationship with said shroud-receiving body portion such that said shroud will rotate relative to said fastener body under an applied external torque prior to said fastener body rotating when said fastener body is engaged with an external structure at a design installation torque.