一种面向PDF文本内容审查的高效多模式匹配算法

Multi-pattern matching plays an important role in network intrusion detection and content filtering. To solve the deficiency of Wu-Manber multi-pattern matching algorithm in terms of the achieved matching efficiency and jump distance, propose an improved Wu-Manber algorithm for Chinese PDF document content revciew on the basis of the coding formats of PDF document content. By employing the Bloom filter to extract the curcial information of the pattern string, and exploiting the double hash and PDF document encoding rules, it is shown that the proposed improved algorithm is able to reduce the number of unnecessary matches and increase the jump distance, thus improving the matching efficiency for the content retrieval of PDF document. The practical experimental results confirms the improved matching efficiency for PDF document. When the shortest mode string is long and the mode string size is large, the matching efficiency can be even doubled.