Security Critical Systems in Software
Jonas Frid · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2010
Sectra Communications is today developing cryptographic products for high assurance environments with rigorous requirements on separation between encrypted and un-encrypted data. This separation has traditionally been achieved through the use of physically distinct hardware components, leading to larger products which require more power and cost more to produce compared to systems where lower assurance is required. An alternative to hardware separation has emerged thanks to a new class of operating systems based on the "separation kernel" concept, which offers verifiable separation between software components running on the same processor comparable to that of physical separation. The purpose of this thesis was to investigate the feasibility in developing a product based on a separation kernel and which possibilities and problems with security evaluation would arise. In the thesis, a literature study was performed covering publications on the separation kernel from a historical and technical perspective, and the development and current status on the subject of software evaluation. Additionally, a software crypto demonstrator was partly implemented in the separation kernel based Green Hills Integrity operating system. The thesis shows that the separation kernel concept has matured significantly and it is indeed feasible to begin using this class of operating systems within a near future. Aside from the obvious advantages with smaller amounts of hardware, it would give greater flexibility in development and potential for more fine-grained division of functions. On the other hand, it puts new demands on developers and there is also a need for additional research about some evaluation aspects, failure resistance and performance.