Comparison of two documents in the plagiarism detection context is often reduced to a word to word comparison, a research of copy and paste. In this article, a naïve approach to compare two documents with the aim of automatically detecting whether a copied sentence from one text to the other, or paraphrases and reformulations, is presented. This is achieved by looking for the existence of meaningful words and their potential substitution words. We compare three algorithms using this approach and retain only the most efficient one to evaluate it with existing methods. The goal is to enable detection of similarities between two texts using only keywords. The proposed approach can detect non paraphrastic reformulations, which are impossible to detect with the conventional alignment approach.