Shared Pins

What shared pins are in practice

Shared pins are not just a convenience problem, they are a shared-secret problem. When multiple people know the same code, the pin stops identifying a person and starts identifying a group, which makes it much harder to tell who actually unlocked a session, approved an action, or opened another user’s data.

The pattern is most common in shared terminals, kiosks, shift-based workstations, and older line-of-business applications. In those environments, the pin often becomes a shortcut around proper authentication design, especially when users rotate through the same device or application without individual accounts.

Why shared pins weaken accountability

A shared pin removes the audit trail that comes from individual authentication. If everyone uses the same code, logs can show that “a pin” was entered, but not which person used it, so attribution, non-repudiation, and user-level investigations become weak or impossible.

That loss of accountability matters even when the system still requires a username elsewhere, because the pin may be the final step that unlocks a local profile, a cached session, or a protected workflow. The risk is not only unauthorized access, but also confusion about which user is responsible for the resulting action.

Shared pins also encourage informal sharing outside the intended process. Once a code is socially accepted as communal, it tends to spread across shifts, teams, and temporary staff, which makes the access boundary depend more on trust and habit than on policy enforcement.

Where the security exposure comes from

The danger is exposure through reuse, not the pin format itself. If a device or program stores sessions, cached data, or remembered state, one person using the shared code can end up inside another person’s active context or visible data set.

This is especially risky on shared endpoints where multiple users touch the same browser profile, app session, or local workspace. A weak authentication model at the front door can become a data separation failure inside the application, because the code no longer maps cleanly to one identity or one role.

Where shared access is unavoidable, the real control question becomes whether the application still enforces per-user authorization after the pin is entered. If it does not, the pin has effectively become a universal key.

How organisations should think about replacement and control

Shared pins should be treated as a transitional workaround, not a stable access model. The better design is per-user authentication with explicit sign-in, role-based access where needed, and session handling that does not inherit access from the previous user on a reused device.

For operational teams, the practical test is simple: if two people can use the same code and the system cannot later distinguish them, the control is too weak for accountable access. That is true whether the environment is a frontline kiosk, a warehouse terminal, a clinical station, or a back-office application.

When a legacy system still depends on a shared pin, organisations should prefer compensating controls that narrow the blast radius, such as tighter session timeouts, forced re-authentication for sensitive actions, and clear separation between device access and user-level entitlements.

Risk and Threat Considerations

Shared pins create a direct path to unauthorized access, mistaken attribution, and accidental or deliberate misuse of another person’s session. The smaller the trust boundary around the device or application, the easier it is for one user to reach data or actions that were meant for someone else.

Failure mechanism: A common code removes user uniqueness from the authentication step, so the system cannot reliably bind the session, audit trail, or resulting actions to a single person. That opens the door to shared-session abuse, data exposure, and weak incident reconstruction.

Impact: Organisations can lose accountability, misattribute actions, and expose confidential records or workflow state across users, shifts, or departments. In regulated or operationally sensitive settings, that can become both a security problem and a governance failure.

Practitioner Guidance

Why practitioners should care: Shared pins often persist because they are operationally convenient, but convenience hides the cost of lost traceability. If your environment still uses them, the key question is whether the business process truly needs shared authentication or only shared device access.

Governance implication: Assign ownership for every shared-access workflow and decide whether the control is temporary, exception-based, or retired. If the answer is “temporary,” set a clear migration path to individual authentication and per-user session control rather than allowing the workaround to become permanent.

Practitioner takeaway: A shared pin is acceptable only as a narrow exception with compensating controls, because once authentication is shared, accountability and access separation become much harder to prove.

Related resources from NHI Mgmt Group

• How should healthcare organisations replace shared PINs on mobile devices without slowing clinical workflows?
• Why do shared PINs create so much risk for patient data and device security?
• What are the signs that shared PINs are undermining mobile security and data integrity?
• What happens when shared PINs are used on healthcare mobile devices and an incident occurs?