This is an old revision of the document!
Software Assurance (SwA) is (1) The level of confidence that software functions as intended and is free of vulnerabilities, either intentionally or unintentionally designed or inserted as part of the software throughout the lifecycle (DoD); (2) The planned and systematic set of activities that ensure that software life cycle processes and products conform to requirements, standards, and procedures (NASA)
Source: Committee on National Security Systems, CNS 4009 Glossary