![]() Another early recorded use of steganography occurred in ancient Greece when messengers tattooed messages on their shaved heads and concealed the messages with the hair that grew over them afterwards, a technique also used by German spies in the early 20th century (Newman 1940). The word steganography has Greek origins and means ‘concealed writing.’ The original practice can be traced back to around 440 BC when the ancient Greeks hid messages within wax tablets by writing messages on the wood before applying a wax surface (Herodotus 1987). We also give an extended literature review which will serve as a useful introduction to linguistic steganography for those Computational Linguistics readers not familiar with the problem. ![]() We present results from a new human evaluation of the system's output and a simple computational steganalysis of word-frequency statistics which is a more direct evaluation for linguistic steganography. 1 In this article, we extend the previous work by more closely addressing the practical application of the proposed system. Our lexical substitution-based steganography system was previously published in Chang and Clark ( 2010b), in which the system was evaluated automatically by using data from the English lexical substitution task for SemEval-2007. In addition, the system assigns codes to acceptable substitutes using a novel vertex coding method in which words are represented as vertices in a graph, synonyms are linked by edges, and the bits assigned to a vertex represent the code of a particular word. In order to ensure the lexical substitutions in the cover text are imperceptible, the system uses the Google n-gram corpus (Brants and Franz 2006) for checking the applicability of a synonym in context. The proposed steganography system replaces selected cover words with their synonyms, which is the mechanism used to embed information. In this article, we aim at concealing secret information in natural language text by manipulating cover words. This method ensures that each word represents a unique sequence of bits, without cutting out large numbers of synonyms, and thus maintains a reasonable embedding capacity. We develop a novel method in which words are the vertices in a graph, synonyms are linked by edges, and the bits assigned to a word are determined by a vertex coding algorithm. Second, we address the problem that arises from words with more than one sense, which creates a potential ambiguity in terms of which bits are represented by a particular word. First, we use the Google n-gram corpus for checking the applicability of a synonym in context, and we evaluate this method using data from the SemEval lexical substitution task and human annotated data. In this article we propose two improvements to the use of synonym substitution for encoding hidden bits of information. ![]() However, few existing studies have studied the practical application of this approach. ![]() One of the major transformations used in linguistic steganography is synonym substitution. ![]() There is an answer key provided for the multiple choice answers, as well as a blank recording sheet.Linguistic steganography is concerned with hiding information in natural language text. Integrate RL standards here by having students speak or write referencing back to the text to quote explicitly from the text to answer the question and prove their answers. The slides are also set up with questions asking how they know or what clues they used to help them determine the answers. I have used this for grammar/ literacy centers for a quick check as well! There are 8 different slides, which makes for a quick assessment tool for understanding or a quick lesson as a class! This is a great resource that you can use whole group, in partners, small groups, etc. Students will read a sentence containing a complex vocabulary word and have to choose from a list to pick a synonym or antonym for that word. These slides have been created to help my students to think critically about using context clues within a sentence to determine and decode words and/or their meanings. ![]()
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