Abstract: There are two shortcomings for the existing verifiable computation schemes. One is that only the owner who outsourced the computation can verify the result， and the other is when the owner authorizes other users to verify the result， he has to send his secret key to all the authorized users. In order to overcome the problems， an outsourced computation model was proposed which supports the public verification. The description and security model were formalized and a publicly verifiable outsourced computation scheme， which is based on the bilinear map and contains three entities， was also presented. The algorithm implementation and the communication protocol were also described in details. The verification phase in the scheme does not need the owner’s secret key so it can be publicly verifiable. The scheme can be proved to satisfy unforgeability in the security model， and the security can be reduced to the hardness of the l-SBDH problem.

Key words: bilinear map, public verifiable, outsourced computation, unforgeability, verifiable computation