1) We show that it is secure against existential forgeable on adaptively chosen message and ID attack under the random oracle.

2) We can produce 3500 tor forgeable iron, 2800 ton forged, product, 1200 ton aluminum bronze aluminum and 1000 ton cast iron one year.

3) There are many security properties in this scheme, such as privacy, un- forgeable , non-repeatable, traceable, non-repudiation, publicly verification and so on.

4) This paper shows that Chen- Zhu's scheme is universally forgeable, that is, the group authority can forge a valid group signature on an arbitrary message, which stands in any group member.

5) For grinding of middle and high tensile strength metal , such as carbon steel , alloy steel , hard bronze, forgeable cast iron , ect.

6) For processing the high tensile metals: carbon stell common alloy stell, hard bronze forgeable castiron. etc.

7) Function : be applicable to the technics of hardening and tempering heating treatment of batch cast, forgeable piece and auto parts .