Separation of duties

Separation of duties splits a sensitive process so that no single person holds every step. The clerk who requests a payment is not the manager who approves it, and neither of them reconciles the ledger. An individual acting alone can no longer commit and conceal fraud; wrongdoing now requires collusion, which is rarer, riskier, and easier to detect.

The concept threads through several exam domains. In the Clark-Wilson model it is a formal rule: the person who certifies a well-formed transaction must not be the person who executes it. In operations it appears alongside its cousins: dual control (two people needed simultaneously, like two keys for a safe), job rotation (fraud surfaces when someone else takes the desk), and mandatory vacations (schemes that need daily tending collapse). It also reinforces least privilege: each role gets only its slice of the process.

Exam relevance: pick separation of duties when the question’s goal is preventing fraud by a single insider. Distinguish it from dual control (simultaneous action) and from job rotation and mandatory vacations, which are detective rather than preventive. “Developer pushed their own code to production” scenarios are separation of duties failures.