A computer-implemented method includes receiving a plurality of uniform resource locators (URLs), where the URLs identify content files, and where the URLs include at least one parameter. Fingerprints of the content files are identified. A first entropy of values of the fingerprints conditional on values of a first parameter is determined, and a second entropy of values of the first parameter conditional on values of the fingerprints is determined. It is determined that the first parameter is irrelevant to the identification of a unique content file by the URLs based, at least in part, on the first and second entropy values.
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