Combining the concepts of trust and cloud

the trust evaluation model of security application was discussed from the perspective of subjective.The fuzziness and randomness subjective description to network objects and the reli-ability of the information evaluation could be provided by cloud based trust model（CTM）

and it also

improving the se-curity of network applications

determined the trust level of entire information system.By reviewing the implement prin-ciple

classic improvement and existing problems

the mechanism of CTM could be analyzed

and the development direc-tions for CTM were pointed out.