With rapid development of IT industry, wide use of internet in all walks of life,and the increasing emergence of various threat models, this paper proposes an important factor in information security- trusted programming technology after a comparison with traditional software quality analysis. Quality attributes and credibility attributes (software complexity, software availability, software reliability and so on) are studied with a focus on the analysis, calculation and measurement of code credibility. This technology expects great utility value to software quality assurance and information security.