Patent ID: 7167825
Filing Date: 2007-01-23
Classification: H04L

Abstract:
1. A device for hiding information in a text having at least one sentence, comprising means for linguistically analyzing the text to produce linguistic text components, the linguistic text components being components of the sentence and the sentence, in addition to at least one additional linguistic text component, having exactly one predicate as a linguistic text component; means for determining a plurality of formulation alternatives for the text, wherein the means for determining is operative to determine the plurality of formulation alternatives wherein the means for determining is adapted to generate the formulation alternatives such that every formulation alternative is grammatically correct for the text and has essentially the same meaning as the text, and that every order of linguistic text components and every synonym ascertained have specific partial information allocated thereto, wherein the partial information allocated to the simultaneously possible formulation alternatives for a sentence result in an overall probability of 1.0 such that arbitrary information can be hidden in the text, wherein the means for determining is operative to use, for the allocation of partial information to the simultaneously possible formulation alternatives, an existing probability distribution or a probability distribution generated in accordance with specific rules known to a device for extracting hidden information from a text; means for selecting a formulation alternative from the plurality of formulation alternatives in such a manner that the partial information that is allocated to the selected formulation alternative corresponds at least to a part of the information to be hidden; and means for outputting a selected formulation alternative forming a modified text, with said information to be hidden being hidden in said modified text, wherein the means for linguistically analyzing includes a parser, wherein the parser is operative to recursively break down the sentence into the text components using a hierarchical tree structure, wherein the parser is further operative to determine the predicate and remaining elements of the sentence and to recursively search a linguistic head within the remaining elements of the sentence until the text components of the sentence are obtained, wherein the parser includes a dictionary/grammar stage having an entry for the predicate or the linguistic head, wherein the means for determining is operative to use the entry for the predicate and the linguistic head to exclude parsing alternatives resulting in grammatically incorrect formulation alternatives, and wherein the means for determining is operative to leave a sentence unchanged when valid formulation alternatives can not be found.