Audit C++ code (Simply look over a code and tell if everything is in order eg. no encryption, malicious code etc)

Hi, I need to hire a few experienced C++ developers to look over a project for me. The program is a simple data recovery programs. I don't know how many lines of code are there in the project, but if you give me instructions on how to find this information I shall provide it to you. What I need is for someone who knows their way around C++ (Visual studio 2008) to look through the code and tell me if there is anything to be alarmed about such has encrypted parts of the code, malicious code of any kind etc. I will be hiring 3 separate people to test the code to make sure no one misses anything. If you miss something that the other developers catch than you will not be paid. If however everyone comes up with the same results everyone will get paid. Once the testing is over, I may also be interested in offering one of the developers a project to improve the features of the program.