According to NIST SP 800-64 Rev 2 (withdrawn) the system development life cycle is broken down into five phases. Which of the following is not one of…

According to the withdrawn NIST Special Publication 800-64 Revision 2, the System Development Life Cycle (SDLC) is defined by five distinct phases. These phases are: (1) Initiation, (2) Acquisition/Development, (3) Implementation/Assessment, (4) Operations/Maintenance, and (5) Sunset (Disposal). While testing is a critical activity for security and system functionality, it is not considered a standalone phase in this model. Instead, testing activities are integrated as a key component within the Implementation/Assessment phase, where the system and its security controls are verified and validated before deployment.

A. Implementation/assessment: This is explicitly listed as the third phase in the NIST SP 800-64 Rev 2 SDLC model.

C. Initiation: This is explicitly listed as the first phase in the NIST SP 800-64 Rev 2 SDLC model.

D. Acquisition/development: This is explicitly listed as the second phase in the NIST SP 800-64 Rev 2 SDLC model.

E. Operation/maintenance: This is explicitly listed as the fourth phase in the NIST SP 800-64 Rev 2 SDLC model.

F. Sunset(disposal): This is explicitly listed as the fifth and final phase in the NIST SP 800-64 Rev 2 SDLC model.

1. National Institute of Standards and Technology (NIST). (2008). Special Publication 800-64 Revision 2: Security Considerations in the System Development Life Cycle. Section 2, "THE SYSTEM DEVELOPMENT LIFE CYCLE," Page 4. (Document is withdrawn but is the specific source for the question).

2. National Institute of Standards and Technology (NIST). (2018). Special Publication 800-37 Revision 2: Risk Management Framework for Information Systems and Organizations. Appendix F.1, "SYSTEM DEVELOPMENT LIFE CYCLE PHASES," Page 123. This current document references the same five-phase SDLC model.

3. George Mason University, Volgenau School of Engineering. (n.d.). CYSE 211: Secure Software and System Development Course Materials. Lecture notes on "Security in the SDLC" describe the NIST SDLC model, identifying the five phases and placing testing activities within the Implementation/Assessment phase.