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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →The Chinese Wall technique is a history-dependent access-control policy that limits conflicts of interest: after a user accesses one company’s data, the policy blocks access to competing companies’ data in the same conflict-of-interest class. It is also used to describe organizational information barriers, but those arrangements are not identical to the formal Brewer–Nash model.
What the Chinese Wall technique means in information security
In computing, “Chinese Wall” commonly refers to the Brewer–Nash security model, a policy designed to protect client confidentiality when an organization serves competing companies. It groups information into company datasets and groups competing datasets into conflict-of-interest classes. A user—called a subject in the model—may access data for only one company in each such class.
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Unlike a policy based only on fixed document labels, Brewer–Nash decisions depend on what the user has accessed before. The initial choice within a conflict class is open; subsequent access is constrained by that choice. Brewer and Nash presented the policy in 1989 at the IEEE Symposium on Security and Privacy. They described it as: “The Chinese Wall policy combines commercial discretion with legally enforceable mandatory controls.” That statement concerns their model and its setting, not a universal claim about current law.
How the Brewer–Nash model decides access
Imagine a consultancy with datasets for competing companies A and B, grouped in the same conflict class. Before accessing either company’s dataset, a consultant has not yet made a choice in that class. If the consultant accesses A’s data, access to B’s data is then denied under the model. The consultant may continue accessing A’s data and may access datasets in other conflict classes, subject to those classes’ own histories.
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- Group data by company. Treat each company’s information as a company dataset.
- Define conflict classes. Put datasets for competitors into the same class.
- Track a user’s access history. The first access within a class establishes which company dataset the user may continue to access there.
- Apply the restriction to later requests. Permit access consistent with that history and deny access to competing datasets in that class.
This describes the policy rule, not a claim that every organization implements it identically. How an organization classifies companies and data is central to how the rule operates.
How a Chinese Wall differs from an organizational information barrier
Businesses and regulators also use “Chinese wall” more broadly for arrangements that restrict the flow or use of sensitive information between parts of an organization. These arrangements may involve people, processes, and physical separation, rather than relying solely on an access-control system that tracks a user’s prior dataset access.
- United Kingdom: The Financial Conduct Authority’s SYSC 10.2 describes an arrangement requiring information held by a person in one part of a firm to be withheld from, or not used by, people acting in another part. The rules also address attribution of knowledge when individuals are effectively separated by such an arrangement. Read FCA SYSC 10.2.
- Hong Kong: The Securities and Futures Commission discusses functional barriers between corporate-finance activities and other business activities. Its guidance calls for controls to prevent the flow of confidential or price-sensitive information, including physical separation and different staff. Read the SFC Corporate Finance Adviser Code of Conduct.
These are jurisdiction- and activity-specific regulatory examples, not a single legal definition applicable everywhere. A formal Brewer–Nash access rule and a firm’s broader information-barrier arrangements may be related, but they should not be treated as interchangeable.
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A Chinese Wall policy is a way to constrain access or information flows; its name alone does not establish that a firm has implemented effective controls, resolved every conflict, or met every legal or professional obligation. The 1989 paper and the cited FCA and SFC materials do not provide a general measured effectiveness rate or adoption figure.
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For a live matter, the relevant jurisdiction, business activity, facts, and professional rules determine what controls are required. The FCA example concerns UK regulatory rules, while the SFC guidance concerns Hong Kong corporate-finance advisers.
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