Method and system for establishing enhanced key when terminal moves to enhanced universal terminal radio access network (UTRAN)

A system for establishing an enhanced key when a terminal moves from an evolved universal terrestrial radio access network (EUTRAN) to an enhanced universal terrestrial radio access network (UTRAN), comprising a terminal and a target enhanced serving general packet radio service support node (SGSN+) in the enhanced UTRAN;

• wherein,
• the SGSN+ is configured to:
• when the terminal moves from the EUTRAN to the enhanced UTRAN, deduce an intermediate key used in the enhanced UTRAN according to a mapped traditional key obtained from a source mobility management entity;
• and
• the terminal is configured to:
• deduce the mapped traditional key, and, after deducing and obtaining the mapped traditional key, further deduce the intermediate key used in the enhanced UTRAN by using an algorithm which is the same as that of the SGSN+ according to the mapped traditional key;
• wherein the enhanced UTRAN supports high speed packet access evolution (HSPA+) security function.