This report describes a selection of tools used to achieve trustworthy software, with the aim to give an overview of the current status of the research within the area of trustworthy software. The selection is based on the authors' literature surveys during the projects Technique for IT Security and Trustworthy IT Platforms. The report presents the knowledge attained in the projects on a comprehensive level. A certain overlap with material published in other reports in the projects is therefore present. The different classes of tools covered in the report are (1) formal methods, (2) standards, (3) organisations, (4) secure programming languages, (5) vulnerability prediction and (6) secure operating systems. These classes of supporting tools are presented briefly and explained on a basic level. The report is a support for those in the Swedish Armed Forces that need to gain knowledge within the area of trustworthy software. The conclusions drawn from the study are that research and development of technology giving trustworthy software have increased recently, but have not yet reached a maturity level allowing commercial use. Standards and certification are used regularly. Software development tools based on formal methods are showing promising results, but still often require special solutions to be useful.