Attacks on?l-diversity This is useful because in real data sets attribute values may be skewed or semantically similar. However, accounting for value distributions may cause difficulty in creating feasible?l-diverse representations. The?l-diversity technique is useful in that it may hinder an attacker leveraging the global distribution of an attribute's data values in order to infer information about sensitive data values. Not every value may exhibit equal sensitivity, for example, a rare positive indicator for a disease may provide more information than a common negative indicator. Because of examples like this,?l-diversity may be difficult and unnecessary to achieve when protecting against attribute disclosure. Alternatively, sensitive information leaks may occur because while?l-diversity requirement ensures 便宜美国vps “diversity” of sensitive values in each group, it does not recognize that values may be semantically close, for example, an attacker could deduce a stomach disease applies to an individual if a sample containing the individual only listed three different stomach diseases.
Formal definition[edit] Given the existence of such attacks where sensitive attributes may be inferred based upon the distribution of values for?l-diverse data, the?t-closeness method was created to further?l-diversity by additionally maintaining the distribution of sensitive fields. The original paper[1]?by xndxs, 迷路的可乐, and?jzddb?defines?t-closeness as:
The?t-closeness Principle:?An equivalence class is said to have?t-closeness if the distance between the distribution of a sensitive attribute in this class and the distribution of the attribute in the whole table is no more than a threshold?t. A table is said to have?t-closeness if all equivalence classes have?t-closeness.
References[edit] Jump up^?xndxs, 迷路的可乐, and jzddb (2007).?"t-Closeness: Privacy beyond?k-anonymity and?l-diversity"?(PDF).?ICDE. Purdue University.?doi:10.1109/ICDE.2007.367856.Jump up^?Charu C. Aggarwal; Philip S. Yu, eds. (2008). "A General Survey of Privacy".?Privacy-Preserving Data Mining – Models and Algorithms?(PDF). Springer.?ISBN?978-0-387-70991-8.
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